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Full text of "Federal motor vehicle safety standards and regulations, with amendments and interpretations"

FEDERAL MOTOR VEHICLE SAFETY STANDARD NO. 100 

Controls and Displays 
(Docket No. 1-18; Notice 31) 



51. Scope. This standard specifies require- 
ments for the location, identification, and illumina- 
tion of motor vehicle controls and displays. 

52. Purpose. The purpose of this standard is to 
ensure the accessibility and visibility of motor vehi- 
cle controls and displays and to facilitate their 
selection under daylight and nighttime conditions, 
in order to reduce the safety hazards caused by the 
diversion of the driver's attention from the driving 
task, and Ijy mistakes in selecting controls. 

53. Application. This standard applies to 
passenger cars, multipurpose passenger vehicles, 
trucks, and buses, manufactred befor September 1, 
1989. at the option of the manufacturer, motor 
vehicles may comply with the requirements of 
Federal Motor Vehicle Safety Standards No. 101, 
Controls and Displays, instead of the requirements 
of this standard, for any control, display, or il- 
lumination. 

54. Definitions. 

"Telltale" means a display that indicates, by 
menas of a light-emitting signal, the actuation of a 
device, a correct or defective functioning or condi- 
tion, or a failure to function. 

"Gauge" means a display that is listed in S5.1 or 
in Table 2 and is not a telltale. 

"Informational readout display" means a display 
using light-emitting diodes, liquid crystals, or 
other electro illuminating devices where one or 
more than one type of information or message may 
be displayed. 

55. Requirements, (a) Except as provided in 
paragraph (b) of this section, each passenger car, 
multipurpose passenger vehicle, truck, and bus 
manufactured with anv control listed in So.l or in 



column 1 of Table 1, and each passenger car, 
multipurpose passenger vehicle and truck or bus 
less than 10,000 pounds GVWR with any display 
listed in S5.1 or in column 1 of Table 2, shall meet 
the requirements of this standard for the location, 
identification, and illumination of such control or 
display. 

(b) For vehicles manufactured before September 
1, 1987, a manufacturer may, at its option— 

(1) Meet the requirements in this standard to use 
identifying words or abbreviation or identifying 
symbol for a control by using those specified in 
Table 1(a) instead of Table 1. If none are specified 
in Table 1(a), none need be used for the control. 

(2) Meet the requirements in this standard to use 
identifying words or abbreviation or identifying 
symbol for a display by using those specified in 
Table 2(a) instead of Table 2. If none are specified 
in Table 2(a), none need by used for the display. 

S5.1 Location. Under the conditions of S6, each 
of the following controls that is furnished shall be 
operable by the driver and each of the following 
displays that is furnished shall be visible to the 
driver. Under conditions of S6, telltales and infor- 
mational readout displays are considered visible 
when activated. 

HAND-OPEEyiTED CONTOOIS 

(a) Steering wheel. 

(b) Horn. 

(c) Ignition. 

(d) Headlamp. 

(e) Tail lamp. 

(f) Turn signal. 

(g) Illumination intensity, 
(h) Windshield wiper. 



PART 571; S 100-1 



(i) Windshield washer. 

(j) Manual transmission shift lever, except 
transfer case. 

(k) Windshield defrosting, and defogging 
system. 

(1) Rear window defrosting and defogging 
system. 

(m) Manual choke. 

(n) Driver's sun visor. 

(o) Automatic vehicle speed system. 

(p) Highbeam. 

(q) Hazard warning signal. 

(r) Clearance lamps. 

(s) Hand throttle. 

(t) Identification lamps. 

Foot-Operated Controis 

(a) Service brake. 

(b) Accelerator. 

(c) Clutch. 

(d) Highbeam. 

(e) Windshield washer. 

(f) Windshield wiper. 

Displays 

(a) Speedometer. 

(b) Turn signal. 

(c) Gear position. 

(d) Brake failure warning. 

(e) Fuel. 

(f) Engine coolant temperature. 

(g) Oil. 

(h) Highbeam. 

(i) Electrical Charge. 

S5.2 Identification. 

S5.2.1 Vehicle controls shall be identified as 
follows: 

(a) Except as specified in S5.2.1(b), any hand- 
operated control listed in column 1 of Table 1 that 
has a symbol designated in column 3 shall be iden- 
tified by that symbol. Any such control for which 
no symbol is shown in Table 1 shall be identified by 
the word or abbreviation shown in column 2, if 
such word or abbreviation may be used at the 
manufacturer's discretion for the purpose of clear- 
ity. Any such control for which column 2 of Table 1 
and/or column 3 of Table 1 specifies "Mfr. Option' 
shall be indentified by the manufacture's choice of 
a symbol, word or abbreviation, as indicated by 
that specification in column 2 and /or column 3. 



The identification shall be placed on or adjacent to 
the control. The identification shall, under the con- 
ditions of S6, be visible to the driver and, except as 
provided in S5.2.1.1 and S5.2.1.2, appear to the 
driver perceptually upright. 

(b) S5.2.1(a) does not apply to a turn signal con- 
trol which is operated in a plane essentially parallel 
to the face plane of the steering wheel in its normal 
driving position and which is located on the left 
side of the steering column so that it is the control 
on that side of the column nearest to the steering 
wheel face plane. 

55.2.1.1 The identification of the following need 
not appear to the driver perceptually upright: 

(a) A master lighting switch or headlamp and 
tail lamp control that adjusts control and display 
illumination by means of rotation, or of any other 
rotating control that does not have an off position. 

(b) A horn control. 

55.2.1.2 The identification of a rotating control 
other than one described by S5.2.1.1 shall appear 
to the driver perceptually upright when the control 
is in the off position. 

S.5.2.2 Identification shall be provided for each 
function of any automatic vehicle speed system 
control and any heating and air conditioning 
system control, and for the extreme positions of 
any such control that regulates a function over a 
quantitative range. If this identification is not 
specified in Tables 1 or 2, it shall be in word or sym- 
bol form unless color coding is used. If color coding 
is used to identify the extreme positions of a 
temperature control, the hot extreme shall be iden- 
tified by the color red and the cold extreme by the 
color blue. 

Example 1 A slide lever controls the 
temperature of the air in the vehicle heating 
system over a continuous range, from no heat 
to maximum heat. Since the control regulates a 
single function over a quantitative range, only 
the extreme positions require identification. 

Example 2 A switch has three positions, for 
heat, defrost, and air conditioning. Since each 
position regulates a different function, each 
position must be identified. 

S5.2.3 Any display located within the passenger 
compartment and listed in column 1 of Table 2 that 
has a symbol designated in column 4, 



PART 571; S 100-2 



Table 1 
Identification and Illumination of Controls 



Column 1 


Column 2 


Column 3 


Column 4 


Hand Operated Controls 


Identifying Words 
or Abbreviation 


Identifying 
Symbol 


Illumination 


Master Lighting 
Switch 












Headlamps and 
Tail lamps 


(Mfr. Option)2 


(Mfr. Option)2 






Horn 




ter ' 








Turn Signal 




«* : 








Hazard Warning 
Signal 




A ' 


Yes 




Windshield Wiping 
System 




V 


Yes 




Windshield Washing 
System 




^ 


Yes 




Windshield Washing 
and Wiping Combined 




^ 


Yes 




Heating and or Air 
Conditioning Fan 




it - 88 


Yes 




Windshield Defrosting 
and Befogging System 




W 


Yes 




Rear Window Defrosting 
and Defogging System 




U 


Yes 




Identification, Side 

Marker and or Clearance 

Lamps 




-;oo:- " 

5 


Yes 




Manual Choke 


Choke 










Engine Start 


Engine Start^ 










Engine Stop 


Engine Stop' 




Yes 




Hand Throttle 


Throttle 










Automatic Vehicle Speed 


(Mfr. Option) 




Yes 




Heating and Air 

Conditioning 

System 


(Mfr. Option) 


(Mfr. Option) 


Yes 



Use when engine control is separate from the key locking system. 
Separate Identification not required if controlled by master lighting switch. 
The pair of arrows is a single symbol. When the controls for left and right turn 
considered separate symbols and may be spaced accordingly. 
Identification not required for vehicles with a GVWR greater than 10.000 lbs. 
Framed areas may be filled. 



operate independently, however, the two arrows may be 
, or for narrow ring-type controls. 



PART 571; S 100-3 



TABLE 1(a) 
Identification and Illumination of Controls 



Column 1 


Column 2 


Col. 3 


Col. 4 


Hand Operated Controls 


Identifying Words or Abbreviation 


Identifying Symbol 


Illumination 










Headlamps and 
Tail Lamps 


Lights 


ID : 






Turn Signal 




<^^ 








Hazard Warning 
Signal 


Hazard 


A ' 


Yes 


Clearance Lamps 
System 


Clearance Lamps or CI Lps 


-:od:- : 


Yes 


Windshield Wiping 
System 


Wiper or Wipe 


V 


Yes 


Windshield Washing 
System 


Washer or Wash 


<& 


Yes 


Windshield Washing 
and Wiping Combined 


Wash-Wipe 


# 


Yes 


Heating and/or Air 
Conditioning Fan 


Fan 


» 


Yes 


Windshield Defrosting 
and Defogging System 


Defrost, Defog or Def 


^ 


Yes 


Rear Window Defrosting 
and Defogging System 


Rear Defrost, Rear Defog 
or Rear Def 


^ 


Yes 


Engine Start 


Engine Start' 










Engine Stop 


Engine Stop' 




Yes 




Manual Choke 


Choke 










Hand Throttle 


Throttle 










Automatic Vehicle Speed 


(Mfr. Option) 




Yes 




Identification Lamps 


Identification Lamps or Id Lps 




Yes 




Heating and Air 

Conditioning 

System 


(Mfr. Option) 




Yes 





' Use when engine control is separate from the key locking system. 

2 Use also when clearance, identification, parking and/or side marker lamps are controlled with the headlamp switch. 

3 Use also when clearance lamps, identification lamps and/or side marker are controlled with one switch other than the headlamp switch. 
* Framed areas may be filled. 



PART 571; S 100-4 



Table 2 
Identification and Illumination of Displays 



Column 1 


Column 2 


Column 3 


Column 4 


Column 5 


Display 


Telltale 
Color 


Identifying Words 
or Abbreviation 


Identifying 
Symbol 


Illumination 


Turn Signal 
Telltale 


Green 


Also see 
FMVSS 108 


<><■ : 






Hazard Warning 
Telltale 


Red" 


Also see 
FMVSS 108 


A : 






Seat 

Belt 

Telltale 


Red" 


Fasten Belts or 

Fasten Seat Belts. 

Also see 

FMVSS 208. 


'rr or ^Tr 






Fuel Level 
Telltale 


Yellow 


Fuel 


».ffi 






""Gaiig^ 


■ ■■ 


Yes 




Oil Pressure 
Telltale 


Red" 


Oil 


tr. 






Gauge 




Yes 




Coolant Temperature 
Telltale 


Red" 


Temp 


J- 






Gauge 




Yes 




Electrical Charge 
Telltale 


Red" 


Volts, Charge 
or Amp 


d 






Gauge 




Yes 




Highbeam 
Telltale 


Blue or 
Green" 


Also see 
FMVSS 108 


10 • 






Malfunction in 
Anti-Lock or 

Brake System 


Yellow 
Red" 


Antilock or Anti-lock 
Also see FMVSS 105 

Brake. Also 
see FMVSS 105 
















Brake Air Pressure 
Position Telltale 


Red" 


Brake Air Also 
see FMVSS 121 










Speedometer 




MPH5 




Yes 




Odometer 




3 














Automatic Gear 
Position 




Also see 
FMVSS 102 




Yes 







' The pair of arrows is a single symbol When the indicator for left and right turn operate independently, however, the two arrows will 
be considered separate symbols and may be spaced accordingly. 

2 Not required when arrows of turn signal telltales that otherwise operate independently flash simultaneously as hazard warning telltale. 

3 If the odometer indicates kilometers then "KILOMETERS" or "km" shall appear, otherwise, no identification is required. 
' Red can be red-orange. Blue can be blue green. 

5 If the speedometer is graduated in miles per hour and in kilometers per hour, the identifying words or abbreviations shall be "MPH 
and km/h" in any combination of upper or lower case letters. 

6 Framed areas may be filled. 



PART 571; S 100-5 



Table 2 (a) 
Identification and Illumination of Internal Displays 



Column 1 


Col. 2 


Column 3 


Column 4 


Column 5 


Display 


Telltale 
Color 


Identifying Words 
or Abbreviation 


Identifying Symbol 


Illuminate 


Turn Signal 
Telltale 


Green 


Also see 
FMVSS 108 


^^ ; 






Hazard Warning 
Telltale 


Red" 


Also see 
FMVSS 108 


A : 






Seat Belt 
Telltale 


Red" 


Fasten Belts or 

Fasten Seat Belts. 

Also see 

FMVSS 208. 


A 






Fuel Level 
Telltale 


Yellow 


Fuel 


^ 






Gauge 




Fuel 


Yes 


Oil Pressure 
Telltale 


Red" 


Oil 


•t^. 






S'auge 




6\\ ~ 


Yes 


Coolant Temperature 
Telltale 


Red" 


Temp 


-t 






Gaug"!"" ~ 




Temp 


Yes 


Electrical Charge 
Telltale 
Gauge 


Red" 


Volts, Charge 
or Amp 

Volts, Charge 
or Amp 


Q 




Yes 




Speedometer 




MPH6 




Yes 






Odometer 


















Automatic Gear 
Position 




Also see 
FMVSS 102 




Yes 






•^ High Beam 
Telltale 


Blue" 

or 
Green 


Also see 
FMVSS 108 


ID 






Position 
Telltale 


Red" 


Brake Air 

Also See 

FMVSS 121 










Malfunction in 
Anti-Lock or 


Yellow 


Anti-Lock Also see 
-FMVSS 105 75 










Brake System 


Red" 


Brake Also see 
FMVSS 105 75 















The pair of arrows is a single symbol. When the indicator for left and nght turn operate independently, however, the two arrows will 

be considered separate symbols and may be spaced accordingly. 

Not required when arrows of turn signal telltales that otherwise operate independently flash simultaneously as hazard warning telltale 

If the odometer indicates kilometers, then "KILOMETERS" or "km" shall appear; otherwise no identification is required. 

Red can be red orange Blue can be blue green. 

Framed arrows may be filled. 

If the speedometer is graduated in miles per hour and in kilometers per hour, the identifying words or abbreviations shall be "MPH 

and km/h" in any combination of upper or lower case letters. 

PART 571; S 100-6 



shall be identified by that symbol. Such display 
may, in addition be identified by the word or 
abbreviation shown in column 3. Any such display 
for which no symbol is provided in Table 2 shall be 
identified by the word or abbreviation shown in 
column 3. Informational readout displays may be 
identified by the symbol designated in colum 4 of 
Table 2 or by the word or abbreviation shown in 
column 3. Additional words or symbols may be 
used at the manufacturer's discretion for the pur- 
pose of clarity. The identification required or per- 
mitted by this section shall be placed on or adjacent 
to the display that it identifies. The identification 
of any display shall, under the conditions of S6, be 
visible to the driver and appear to the driver 
perceptually upright. 
S5.3 Illumination. 

55.3.1 Except for foot-operated controls or 
hand-operated controls mounted upon the floor, 
floor console, or steering column, or in the wind- 
shield header area, the identification required by 
5 5.2.1 or § 5.2.2 of any control listed in column 1 
of Table 1 and accompanied by the word "yes" in 
the corresponding space in column 4 shall be 
capable of being illuminated whenever the 
headlights are activated. However, control iden- 
tification for a heating and air-conditioning system 
need not be illuminated if the system does not 
direct air directly upon windshield. If a gauge is 
listed in column 1- of Table 2 and accompanied by 
the word "yes" in column 5, then the gauge and its 
identification required by § 5.2.3 shall be 
illuminated whenever the ignition switch and /or 
the headlamps are activated. Controls, gauges, and 
their identifications need not be illuminated when 
the headlamps are being flashed. A telltale shall 
not emit light except when identifying the mal- 
function or vehicle condition for whose indication it 
is designed or during a bulb check upon vehicle 
starting. 

55.3.2 Except for informational readout 
displays each discrete and distinct telltale shall be 
of the color shown in column 2 of Table 2. The iden- 
tification of each teletale shall be in a color that 
contrasts with the lens, if a telltale shall be iij a 
color that contrasts with the lens, if a telltale with 
a lens is used. Any telltale used in conjunction with 
a gauge need not be identified. The color of infor- 
matinal readout displays will be at the option of the 
manufacturer. 



S5.3.3 Light intensities for contorls, gauges, 
and their identification shall be continuously 
variable from: (a) A position at which either there 
is no light emitted or the light is barely discernible 
to a driver who has adapted to dark ambient road- 
way conditions to (b) a position provided illumina- 
tion sufficient for the driver to identify the control 
or display readily under conditions of reduced 
visibility. Light intensities for informational 
readout systems shall have at least two values, a 
higher one for day, and a lower one for nighttime 
conditions. The intensity of any illumination that is 
provided in the passenger compartment when and 
only when the headlights are activated shall also be 
variable in a manner that complies with this 
paragraph. The light intensity of each telltale shall 
not be variable and shall be such that, when ac- 
tivated, that telltale and its identication are visible 
to the dirver under all daytime and nighttime con- 
ditons. 

S6 Conditions. The driver is restrained by the 
crash potention equipment installed in accordance 
with the requirements of § 571.208 of this part 
(Standard No. 208), adjusted in accordance with 
the manufacturer's instructions. * * * 

3. Section 571.101 is amended by revising S3 to 
read: 

S3. Application. This standard applies to 
passenger cars, multipurpose passenger vehicles, 
trucks, and buses. At the option of the manufac- 
turer, motor vehicles manufactured before 
September 1, 1989, may comply with the require- 
ments of Federal Motor Vehicle Safety Standard 
No. 100, Controls and Displays, instead of the re- 
quirements of this standard, for any control, 
display, or illumination. If no requirements are 
specified in Standard No. 100 for a control, 
display, or illumination, none need be met as a 
result of this standard for motor vehicles manufac- 
tured before September 1, 1989 

***** 

Issued on March 4, 1987 

Diane K. Steed 
Administrator 
52 F.R. 7150 
March 9, 1987 



PART 571; S 100-7-8 



PREAMBLE TO FEDERAL MOTOR VEHICLE SAFETY STANDARD NO. 101-80 



Controls and Displays 
(Docket No. 1-18; Notice 13) 



Action: Final rule. 



Summary: This notice expands the applica- 
tion of the standard for the location, identifica- 
tion, and illumination of driver controls and 
displays (e.g., gauges and meters) by establishing 
requirements for additional controls and by in- 
troducing selected displays which, if furnished, 
must be located and illuminated under specified 
conditions and identified by a specified symbol 
and/or selected word. The purpose of the re- 
quirements is to encourage international stand- 
ardization and harmonization of controls and 
displays in order to convey information more 
quickly to drivers and with less chance of human 
error. This will reduce the interval during which 
a driver's attention is diverted from the roadway 
to his controls and displays, thus decreasing the 
possibility of an accident. 

Effective date: September 1, 1980. 

For further information contact : 

Mr. Nelson Erickson, Ofiice of Motor Vehicle 
Programs, 400 Seventh Street, S.W., Wash- 
ington, D.C. 20590, 202^26-2155. 

Supplementary information: This notice estab- 
lishes new requirements for the location, identifi- 
cation, and illumination of controls and displays 
in passenger cars, multipurpose passenger ve- 
hicles, trucks, and buses. The new rule is desig- 
nated 49 CFR 571.101-80, Controls and Displays, 
and becomes effective September 1, 1980. The 
existing rule on this subject, 49 CFR 571.101, 
Control Location, Identification, and Illu?>iina- 
tion, is amended to permit, at the vehicle 
manufacturer's option, compliance with that 
standard or the new requirements of Standard 
No. 101-80 before September 1, 1981. 



On October 21, 1976, the National Highway 
Traffic Safety Administration published (41 FR 
46460) a notice proposing to update the existing 
controls and displays standard (Standard 101) 
by incorporating all pertinent amendments and 
interpretations publislied since the original issu- 
ance on January 31, 1967. It also proposed to 
consolidate the control and display requirements 
of other standards in one I'egulation. This notice 
takes final action on that proposal. All com- 
ments were considered and the major ones are 
discussed below. 

The notice issued in October 1976 proposed 
that most controls and displays be required to 
be identified with specified symbols which are 
internationally standardized. Words would have 
been permitted in addition to the symbols, 
although the choice of words would have been 
limited to ensure uniformity. Specified words 
would have been required for those controls and 
displays for which no symbols had been estab- 
lished. 

The rationale behind the proposed requirement 
of symbols was that they can convey infonnation 
more quickly and with less chance of human 
error than words. This is particularly true with 
respect to the large foreign language speaking 
population of this country. By simplifying the 
identification of controls and displays, the stand- 
ard should reduce the problems resulting from 
driver's attention being diverted from the road- 
way to his controls and displays. An individual 
benefit cited in the proposed notice is that manu- 
facturers who sell vehicles both in and outside 
of the United States could realize significant 
cost savings by utilizing internationally stand- 
ardized symbols. 



PART 571; S 101-80— PRE 1 



The National Motor Vehicle Advisory Council 
and the Vehicle Equipment Safety Commission 
did not take jwsitions on the proposal. The ma- 
jority of commenters favored the use of symbols 
in the interest of international standardization 
and harmonization. The final rule, therefore, re- 
quires the use of symbols and allows the use of 
additional words if the manufacturer so chooses. 

One of the major concerns of manufacturers 
commenting was tliat the proposed rule would 
inhibit the design and development of electronic 
"readout" panels which can effectively present 
to the driver specific information concerning ve- 
hicle and environmental conditions affecting 
safety. These displays are currently capable of 
exhibiting information and warnings with word 
messages and not with symbols. The optional 
use of symbols or words will permit the con- 
tinued development of informational readout 
displays. The NHTSA supports the develop- 
ment of more efficient and effective control and 
display information systems and has, conse- 
quently, permitted informational readout dis- 
plays to be identified by words only so as to not 
impede the development of electronic displays. 

The symbols that are permitted by this rule 
to identify controls and displays are those de- 
veloped by the International Standards Organi- 
zation (ISO). By specifying symbols adopted 
by the ISO, this agency is facilitating the 
achievement of an international uniform identifi- 
cation system. New symbols for five controls 
and eight displays are added to those presently 
designated in the existing standard. Additional 
symbols will be added when the NHTSA deter- 
mines which ones will be readily recognizable, 
thus reducing driver diversion. 

Some commenters noted that a few of the 
symbols such as the clearance lamp symbol, de- 
viate slightly from those adopted by the ISO. 
The NHTSA, while basing its symbols on those 
developed by the ISO, is not specifying ISO 
symbols which it detennines will not adequately 
convey the intended message. Thus, the symbols 
proposed in the October notice are adopted, 
even though some of them deviate from the ISO 
symbols. Some existing ISO symbols are not 
included in this final rule due to the fact that 
additional data are needed on their recogniza- 
bility. When such data have been accumulated 



and analyzed, the NHTSA will determine 
whether the symbols should be added to Stand- 
ard 101-80. 

A few commenters suggested the deletion of 
the symbols for the turn signal and high beam 
telltales because these have long been identified 
by color and operate only after deliberate opera- 
tion by the driver. It is the belief of the 
NHTSA that these symbols should be retained. 
They are necessary to educate new drivers, to 
act as reminders to those who drive infrequently, 
and to further the uniformity and harmoniza- 
tion of symbols. It should be noted that the 
turn signal was inadvertently omitted from Table 
I. It was, however, listed in S5.1 as one of the 
hand-operated controls and discussed in the pre- 
amble. 

Another question that was raised was whether 
the manufacturers could use symbols that deviate 
from those designated in the standard. As stated 
in previous notices on controls and displays, 
minor deviations are allowed, as long as the 
symbol used substantially resembles that specified 
in the standard. 

Several commenters raised concerns about the 
color of various symbols. The hazard warning 
telltale was inadvertently designated as green 
in the proposed rule. That color should be red 
and the final rule has been corrected to reflect 
this. Several commenters mentioned that because 
of the teclmology of light emitting diodes, tell- 
tales are technologically feasible only in yellow, 
green, or red. One commenter noted that neon 
gas discharge displays emit a characteristic neon 
red-orange light, rather than red. These dis- 
plays rate high in intensity, durability, and 
reliability and are low in cost. Because of these 
factors, the final rule has been amended so that 
a designation of the color i-ed can be either red 
or red-orange and the color blue may be either 
blue or blue-green. 

Many of those commenting objected to the 
prohibition of any words other than the words 
specified in the table. The NHTSA has decided, 
to permit the manufacturer to use additional 
words, but only for clarification. For example, 
the manufacturer may combine an instruction 
with the specified identification, such as "pull to i 
defrost," or it may use another word for the ' 
purpose of clarity, such as "unleaded fuel only." 



PAET 571; S 101-80— PRE 2 



The manufacturer will be permitted to describe 
the "automatic vehicle speed system" in words 
of his choosing because over the years customers 
have become used to the various descriptors, such 
as "cruise control" and "speed control," which 
manufacturers have used. The NHTSA does 
not believe that either descriptor is superior to 
the other. In addition, the manufacturer will 
be permitted to describe the "automatic gear posi- 
tion" by words of his choosing since these con- 
trols are conspicuous and automatic transmissions 
are not unifonn, some not providing a park (P) 
position and others with additional gears. In 
response to one question, it should be noted that 
"automatic gear position" by virtue of its being 
automatic is not a hand-operated control as re- 
ferred to in S5.3.1. 

In accordance with the suggestions of com- 
menters, the final rule adopts the use of "volts" 
or "charge" in addition to "amp" for the elec- 
trical charge telltale and gauge. Many other 
alternate words were suggested, but the NHTSA 
believes that the ones adopted in the final rule 
best convey the appropriate information. With 
the allowance of additional words, objection to 
those required should no longer remain. 

Manufacturers of vehicles over 10,000 pounds 
gross vehicle weight rating (GVWE) objected 
to the application of this rule to their vehicles. 
They emphasized that with the increased number 
of gauges and expanded level of display infor- 
mation utilized by such vehicles, the application 
of this rule would result in panels that are a 
"hodgepodge of sjanbols." It was also asserted 
that this application would necessitate redesign 
of the instrument panels, possibly increasing 
driver diversion instead of decreasing it. Most 
hea\'y duty trucks comply with SAE recom- 
mendations for the location standardization of 
controls and displays in the operator's compart- 
ment. The operators of vehicles in the heavy 
duty category are professionals who are familiar 
with these standardized locations and do not need 
to read a legend or symbol. In addition, heavy 
duty trucks are not subject to yearly redesign 
or model changes. Because of these concerns, 
the agency has decided that vehicles over 10,000 
pounds GVIVTI need not meet display require- 
ments of this standard. They must, however, 
meet the control requirements. 



A large number of commenters requested that 
the location of the controls and displays be uni- 
form. An additional request was made to require 
common carriers to maintain illumination devices 
on all equipment. While these recommendations 
are noteworthy, they are not the subject of this 
rulemaking action, but will be considered for 
possible future rulemaking. 

In the October proposal, it was specfied that 
the control identification be placed on or adjacent 
to the particular control. The display identifica- 
tion, on the other hand, was to be placed on the 
display, unless the exposed portion of the lens 
was in the shape of the required identification. 
The proposal also stated that the identification 
of the high-beam indicator and of any gauge 
could be placed on or adjacent to the display 
that it identified. In response to the comments 
that identification could be met equally well by 
placing the symbol adjacent to the telltale, the 
NHTSA has decided to leave it up to the manu- 
facturer to determine whether the identification 
should be placed directly on the control or dis- 
play or whether an adjacent position would be 
satisfactory. The final rule does require that the 
identification be visible to the driver. In re- 
sponse to one commenter, the NHTSA does 
recognize that the spokes of the steering wheel 
may at times interfere with the visibility of the 
controls and displays. The visibility require- 
ment will be satisfied even if the driver needs 
to make minimal movements toward the front, 
to the left, and to the right to see the identifica- 
tions. The NHTSA has determined that these 
minor necessary movements will have virtually 
no effect on the safe operation of the vehicle. 

The designation of "Km" for kilometres has 
been corrected in the final rule to read "km". 
Any odometer that records distance in kilometres 
must be labeled "KILOMETEES" or "km" so 
as to avoid confusion. The October 1976 pro- 
posal provided an option regarding English or 
metric units for labeling speedometers. Any 
proposal setting forth alternatives implicitly car- 
ries with it the possibility that one or more of 
the alternatives may become mandatory. In 
light of this and in light of the decision in Fed- 
eral Motor Vehicle Safety Standard No. 127, 
43 FR 10919, to require speedometers to record 
speed in both English and in metric, this rule 



PART 571: S 101-80— PRE 3 



requires that both speed scales be labeled so as 
to avoid confusion. Therefore, for dual readings 
of MPH and km/h on speedometers the manu- 
facturer is required to clearly label the appro- 
priate display. 

The proposed effective date for this rule was 
September 1, 1979. Due to the numerous com- 
ments received, indicating that more lead time 
would be desirable in order to permit the conver- 
sion of controls and displays to coincide with 
routine redesign of various vehicle models, an 
effective dat« of September 1, 1980, has been 
adopted. 

The primary authors of this notice are Mr. 
Nelson Erickson, Office of Motor Vehicle Pro- 



grams, and Ms. Kathleen DeMeter, Office of the 
Chief Counsel. 

In consideration of the foregoing. Part 571 
of Title 49 of the Code of Federal Regulations 
is amended. . . . 

(Sees. 103, 119, Pub. L. 89-563, 80 Stat. 718 
(15 U.S.C. 1392, 1407) ; delegation of authority 
at 49 CFR 1.50.) 

Issued on June 21, 1978. 

Joan Claybrook 
Administrator 

43 F.R. 27541 
June 26, 1978 



PART 571; S 101-80— PRE 4 



PREAMBLE TO AN AMENDMENT TO 
FEDERAL MOTOR VEHICLE SAFETY STANDARD NO. 101-80 



Control and Display 
(Docket 1-18; Notice 18) 



ACTION: Interpretative amendment. 



SUMMARY: Standard No. 101-80, Controls and 
Displays, requires various safety-related controls 
to be identified by specific symbols. The standard 
requires identification of the turn signal control 
unless it is the only control on the left hand side of 
the steering column. In addition to the turn signal 
control, some vehicles have additional controls, 
such as a lever to adjust the position of a tilting 
steering wheel, on the left hand side of the col- 
umn. This notice clarifies the identification re- 
quirement to provide that a turn signal control 
does not have to be identified if it is the topmost 
control on the left side of the steering column, the 
traditional position for such controls (i.e., the 
closest control to the steering wheel). 

EFFECTIVE DATE: Date of Publication in the Oc- 
tober 30, 1980 Federal Register. 

FOR FURTHER INFORMATION CONTACT: 

John Carson, Office of Vehicle Safety 
Standards, National Highway Traffic Safety 
Administration, 400 Seventh Street, S.W., 
Washington, D.C. 20590 (202-426-2715) 

SUPPLEMENTARY INFORMATION: On June 26, 
1978, the agency published a final rule establish- 
ing Standard No. 101-80, Controls and Displays 
(43 FR 27541). The standard, which went into 
effect on September 1, 1980, established new 
identification and illumination requirements for 
controls and displays in passenger cars, multipur- 
pose passenger vehicles, trucks and buses. 

One provision of the standard requires the turn 
signal control to be identified by a specific sym- 
bol, two horizontal arrowheads, placed on or adja- 
cent to the control. American Motors Corporation 
(AMC) filed a petition for reconsideration arguing 



that the turn signal identification requirement 
was unnecessary. AMC said that the location and 
operation of column-mounted turn signal control 
levers has been standardized by industry practice 
and is well known to drivers. In response to the 
AMC petition, NHTSA amended the standard to 
delete the identification requirement for vehicles 
in which the turn signal control is the only lever 
mounted on the left side of the steering column. 
The agency explained that it was taking this ac- 
tion because the turn signal control has become 
standardized at that location and there have been 
no reported crashes caused by the driver's un- 
familiarity with the position and use of the turn 
signal control (Sept. 27, 1979, 44 FR 55580). 

Subsequent to the publication of the response 
to the AMC petition for reconsideration, General 
Motors (GM) wrote the agency concerning an in- 
terpretation of the modified requirements. GM 
said that on its vehicles equipped with tilt steer- 
ing columns, there is a tilt mechanism release 
lever located on the same side of the steering col- 
umn as the turn signal control lever. GM said that 
the tilt release lever is "shorter and significantly 
farther from the steering wheel than the turn sig- 
nal lever and consequently is out of the imme- 
diate finger tip reach of a hand remaining on the 
steering wheel." GM said that the tilt wheel 
mechanism is a customer convenience, not a safe- 
ty feature. 

GM argued that its understanding of the agen- 
cy's interpretation of the modified identification 
requirement was that the turn signal control only 
had to be identified "if it is not located and 
operated in what has become to be considered the 
standardized manner or if another functional con- 
trol lever related to vehicle safety could be easily 
confused with it." GM said that based on that in- 
terpretation, it believed that "the presence or 
absence of a tilt column release lever does not 



PART 571; S101-80-PRE 5 



determine whether the turn signal control must be 
identified." To assist all interested parties in inter- 
preting the requirement, GM requested the agency 
to consider revising the language of the standard 
to clarify the agency's intent. 

The purpose of this notice is to make an inter- 
pretative amendment to Standard No. 101-80 to 
clarify the circumstances under which the turn 
signal control must be identified. As an inter- 
pretative amendment, there is no need for notice 
and comment. 

The purpose of the identification requirement is 
to make it easier for the driver to quickly and cor- 
rectly locate various safety-related vehicle con- 
trols. One of the controls that has been standard- 
ized in its location and operation for a number of 
years is the turn signal control. In every car, that 
control is mounted on the left hand side of the 
steering column, is located so that it is the control 
closest to the rim of the steering wheel, and is 
operated in a standardized manner, up for right, 
down for left. Since the turn signal control has 
been standardized for such a long time, it is not 
necessary for the control to include an identifying 
symbol. 



As long as the turn signal control is in its 
standardized location, it will be instantly recog- 
nized by drivers even if there are other controls 
mounted on the same side of the column, farther 
away from the rim of the steering wheel. Thus, to 
clarify the identification requirements, the agency 
is amending the standard. The amendment pro- 
vides that if the turn signal control is mounted on 
the left side of the steering column, in a plane 
essentially parallel to the steering wheel, it need 
not be identified if it is the control mounted closest 
to the rim of the steering wheel. 

In consideration of the foregoing. Standard No. 
101-80 (49 CFR 571.101-80) is revised accordingly. 

Issued on October 22, 1980. 



Frank Berndt 
Acting Administrator 

45 FR 71803 
October 30, 1980 



PART 571; S101-80-PRE 6 



PREAMBLE TO AN AMENDMENT TO PART 571 STANDARD NO. 101-80 

Controls and Displays 
(Docket No. 1-18; Notice 20) 



ACTION: Final rule. 

SUMMARY: This notice amends Standard No. 
101-80, Controls and Displays. The standard 
currently requires the light indicating the 
actuation of the headlamp high beam to be blue. 
(Blue is defined by the standard to include blue- 
green.) This amendment permits manufacturers 
to use the color green as an alternative to blue. 
The purpose of the change is to allow the use of 
light emitting diode technology, which at the 
present time cannot produce the color blue or 
blue-green. 

EFFECTIVE DATE: January 21, 1982. 

SUPPLEMENTARY INFORMATION: Standard 
No. 101-80, Controls and Displays, specifies 
requirements for the identification and 
illumination of controls and displays in passenger 
cars, multipurpose passenger vehicles, trucks and 
buses. The purpose of the standard is to ensure the 
accessibility and visibility of motor vehicle 
controls and displays and to facilitate their quick 
and proper identification and selection by a 
driver in order to reduce the safety hazards 
caused by the diversion of the driver's attention 
from the driving task, and by mistakes in 
selecting controls. 

Among its requirements. Standard No. 101-80 
specifies colors for various vehicle displays. Blue 
is specified for the headlamp high beam telltale 
(i.e., the light indicating that the high beams of 
the headlamps have been activated). A footnote to 
the standard's color requirements (contained in 
Table 2 of the standard) states that blue can be 
blue-green. 

This final rule amends the standard by adding 
green as an alternative to blue and blue-green for 
the headlamp high beam telltale. This final rule 



was preceded by a notice proposing the 
amendment of Standard No. 101-80 in October 1980 
(45 F.R. 71832). Several comments were received 
that supported the proposal, including those 
submitted by General Motors, Ford and Chrysler. 
Only one comment opposed the proposal. The 
NHTSA has considered all of the comments and 
the most significant ones are discussed below. 

The agency proposed to allow the use of green 
as an alternative to blue in response to a petition 
for rulemaking from Volkswagen (VW). Blue had 
been selected by the agency for the headlamp 
high beam telltale primarily to promote 
international harmonization of standards 
regulating vehicle controls and displays. That 
color requirement was the same as that adopted 
by the International Standards Organization, the 
Economic Commission for Europe and the 
European Economic Community. VW petitioned 
for green as an alternative to blue in order to 
enable it to use light emitting diodes (LED's) for 
its telltales. VW stated that its testing has 
demonstrated that LED's are more reliable than 
incandescent bulbs when used for telltales and 
are, thus, very desirable. At present, however, 
LED's cannot be produced in either blue or white 
(which could be used with a blue filter to produce 
blue). VW stated that green is the only color akin 
to blue or blue-green which LED technology is 
capable of producing. 

Ford stated that it supports the proposed 
amendment since it recognizes current 
technological limitations and would allow 
manufacturers to introduce new designs at these 
limits. Ford did express concern, however, that 
the proposed relaxation of the color requirement 
is in conflict with international harmonization of 
U.S. and European motor vehicle standards. That 
company recommended that the proposed 
amendment is issued for an interim period only — 



PART 571; S101-80-PRE 7 



until LED technology can provide commercially 
acceptable blue LED's. Ford's comment stated 
that it believes that blue LED's will become 
commercially feasible for automotive application 
within the next year. 

A comment submitted by General Motors (GM), 
also supporting the proposed amendment, stated 
that it believes that the allowance of a green high 
beam telltale will effectively present the message 
of that telltale, particularly since it must also be 
identified by a symbol. According to GM, the 
amendment will allow incorporation of the current 
electronic technology involving light emitting 
diodes into automotive panel displays. GM stated 
that the allowance of green as a high beam telltale 
color will not affect international harmonization 
since blue will remain an alternative. That 
company noted that any manufacturer desiring to 
market a product worldwide can still choose to 
use a blue telltale and thereby meet the 
international requirements. 

The issue of conflict with international 
harmonization was the basis for the only 
comment received in opposition to the proposed 
amendment. The U.S. Technical Research 
Company (U.S. Technical Representatives of 
Peugeot) stated that under the present state of 
technology, LED's can only display yellow, green 
or red. That company stated that it believes that 
in the near future an amendment of European 
regulations will require that the high beam telltale 
shall be either blue or yellow. According to that 
commenter, if NHTSA chooses to adopt green for 
the high beam telltale, harmonization in this field 
will no longer exist and domestic and foreign 
manufacturers will be equally affected. The U.S. 
Technical Research Company therefore requested 
that NHTSA retain the blue requirement because 
it is identical to the current European 
requirement. Alternatively, that company asked 
the agency to require that either blue or yellow 
telltales be used in anticipation of the possible 
change in the European requirements. 

In the interest of international harmonization 
of standards, Renault also supported permitting 
the use of yellow. However, it also supported 
allowing the use of green as an alternative to 
blue. 

The purpose of requiring telltales to be of a 
particular color is to promote standardization and 
thereby improve driver performance. As noted 



above, the agency adopted blue for the high beam 
telltale primarily to promote international 
harmonization. The International Standards 
Organization, the Economic Commission for 
Europe and the European Economic Community 
all maintain that color requirement. 

The agency does not believe that permitting 
the use of green as an alternative to blue is in 
conflict with international harmonization. As 
noted by GM, any manufacturer desiring to 
market a product worldwide can still choose to 
use a blue telltale and thereby meet the 
international requirements. While the agency is 
aware that some manufacturers and some 
countries in Europe have sought to have 
international standards amended to permit use of 
yellow as an alternative to blue, it is by no means 
certain that those efforts will succeed. Indeed, 
the International Standards Organization rejected 
such a proposal in April 1980. 

In light of the uncertainty of the direction in 
which international requirements will move on 
this matter, the agency determined that yellow 
should not be adopted as an alternative to blue. 
The agency agrees with VW's petition that green 
is the closest color akin to blue or blue-green that 
LED's can produce and thus, in the agency's 
judgment, is the best alternative color to permit. 
To permit use of yellow as well would defeat the 
purpose of having a color requirement in the first 
place, that of promoting standardization and 
thereby improving driver performance. Therefore, 
that alternative was rejected. 

The agency recognizes that the cause of 
international harmonization may make amendment 
of Standard No. 101-80 appropriate if international 
organizations adopt yellow as an alternative to 
blue. The agency will monitor developments in 
this area. 

In the interest of both standardization and 
international harmonization, the agency believes 
that use of green as an alternative to blue should 
only be permitted until LED technology develops 
to the point that it is possible to produce 
commercially acceptable blue LED's. The agency 
considered amending the standard to permit use 
of green for a specified period of time, such as 
three years. However, without more definite 
information indicating when commercially 
acceptable blue LED's will be available, the 
agency determined that it would be more 



PART 571; S101-80-PRE 8 



appropriate to issue the amendment for an 
indefinite period of time. The agency will 
consider limiting high beam telltales to blue after 
blue LED technology has been developed. 

The agency does not believe that this 
amendment will have any adverse effect on 
safety. Even if it did, the effect would be more 
than outweighed by the advantages offered by 
permitting industry the flexibility to use LED 
technology for telltales. As VW pointed out, there 
is evidence that LED's are more reliable than 
incandescent bulbs. 

Comments submitted by Ford and VDO-ARGO 
stated that they see ijo adverse effect on safety as 
a result of this amendment. Further, as noted 
above, GM stated that it believes that a green 
high beam telltale will effectively present the 
message of that telltale, particularly since it must 
also be identified by symbol. No comments were 
received that suggested any adverse effect. 

Also, there may be cost savings and other 
advantages associated with permitting LED's to 
be used for telltales. Standard No. 101-80 already 
permits LED's to be used for other displays. The 
standard defines displays that use LED's to give 
one or more than one type of information or 
message (i.e., using words or symbols) as 
informational readout displays. Recently the 
agency granted a petition for rulemaking from 
GM that requested modification in Standard No. 
101-80's light intensity requirements to permit 
informational readout displays to be used for 
telltales. According to GM, such an amendment 
would permit integration of telltales with other 
instrument displays in a single electronic display 
panel. This step would alleviate instrument panel 
design problems caused by reduced space available 
due to vehicle downsizing and increasing amounts 
and types of information to be presented to the 
driver, offer potential for weight and cost 
reduction, and facilitate placing telltales adjacent 
to displays often consulted by the driver, making 



the telltales more readily noticeable. These same 
types of advantages are offered by permitting 
displays which use LED's, but are not informational 
readout displays (since they consist only of a 
colored light and do not display words or symbols), 
as telltales. 

The agency has assessed the economic and 
other impacts of this final rule and determined 
that it is neither a major rule within the meaning 
of Executive Order 12291 nor a significant rule 
under the Department of Transportation's 
regulatory policies and procedures. Further, the 
agency concludes that the economic and other 
consequences of this final rule are so minimal as 
not to require preparation of a regulatory 
evaluation. The impact is minimal because the 
amendment does not impose any new requirements 
and does not affect compliance costs. Rather, it 
merely permits manufacturers to use an alternate 
color for the high beam telltale. For the same 
reasons, the agency finds that the amendment 
will have no significant environmental impact. 

Although NHTSA has considered the effects of 
this amendment on small businesses, the agency 
has not prepared a regulatory flexibility analysis. 
Such an analysis is not necessary in this case, 
since the Regulatory Flexibility Act applies only 
to rules for which an NPRM was issued on or 
after January 1, 1981. The NPRM for this final 
rule was published in October 1980. 

Issued on January 2, 1982. 



Raymond A. Peck, Jr. 
Administrator 

47 F.R. 2996 
January 21, 1982 



PART 571; S101-80-PRE 9-10 



PREAMBLE TO AN AMENDMENT TO 
FEDERAL MOTOR VEHICLE SAFETY STANDARD NO. 101 

Federal Motor Vehicle Safety Standards; 

Controls and Displays 

[Docket No. 1-18, Notice 25; No. 70-27, Notice 29] 



ACTION: Final rule. 

SUMMARY: Standard No. 101, Controls and 
Displays, specifies requirements for the ac- 
cessibility, identification and illumination of con- 
trols and displays in passenger cars, trucks, and 
buses. This notice amends several of the identifi- 
cation requirements of the standard to improve 
safety by providing easily recognizable, interna- 
tional symbols and to relieve unnecessary restric- 
tions on manufacturers by providing additional 
flexibility in their ability to identify controls and 
displays. This notice also responds to manufac- 
turer petitions. The amendments include replace- 
ing the symbol specified for headlamp/tail lamp 
controls that are part of master lighting switches 
with the International Standards Organization 
(ISO) master lighting switch symbol, while making 
the identification for headlamp/taU lamp controls 
that are separate from master lighting switches at 
the option of the manufacturer; making a minor 
modification in the symbol specified for the 
clearance lamp system control; permitting several 
symbols to be used in solid or outline form; specify- 
ing that horn controls, with limited exceptions, be 
identified by the ISO horn symbol; permitting 
several heating and air conditioning controls to be 
identified by symbols as an alternative to words, 
with the choice of the particular symbols left to the 
discretion of the manufacturer; and making minor 
interpretive amendments. This notice also makes 
minor interpretive amendments in related iden- 
tification requirements of Standard No. 105, 
Hydraulic Brake Systems. 

EFFECTIVE DATE: The amendments are effective 
on July 27, 1984. Some amendments are of an 



optional nature. Others are optional now and 
become mandatory on September 1, 1987. 

SUPPLEMENTARY INFORMATION: Standard 
No. 101, Controls and Displays, speciiies require- 
ments for the accessibility, identification and illu- 
mination of controls and displays in passenger cars, 
multipurpose passenger vehicles, trucks and buses. 
The purpose of the standard is to ensure the acces- 
sibility and visibility of motor vehicle controls and 
displays to a driver and to facUitate their quick 
and proper identification and selection by a driver 
in order to reduce the safety hazards caused by the 
diversion of the driver's attention from the driving 
task, and by mistakes in selecting controls. 

On November 4, 1982, NHTSA published (47 FR 
49993) a notice of proposed rulemaking (NPRM) to 
update Standard No. 101 by adding or modifying 
several symbols to bring the standard into har- 
mony with recent documents promulgated by the 
International Standards Organization (ISO). The 
agency also proposed minor interpretive amend- 
ments. The November 1982 notice was issued in 
light of changing international standards specify- 
ing symbols for the identification of controls and 
displays. These standards include, in addition to 
the ISO standard, those of the United Nations 
Economic Commission for Europe (ECE) and the 
European Economic Community (EEC). The pro- 
posal resulted in part from a petition for rule- 
making submitted by Renault. 

NHTSA received numerous comments on the 
proposal, mostly from manufacturers. Since issu- 
ing the NPRM, the agency has received several 
other petitions for rulemaking from manufacturers 
concerning Standard No. 101, some of which 
followed directly from the proposal. During the 



PART 571; SlOl- PRE 11 



same time period, the agency has also been in the 
process of considering comments and related peti- 
tions concerning a separate earlier NPRM to 
amend other aspects (other than specific symbol 
identification) of Standard No. 101. That proposal 
was published in the Federal Register (47 FR 4541) 
on February 1, 1982. 

The various comments and petitions relating to 
one or the other proposal raise a number of issues, 
many of which are closely interrelated. After 
reviewing all of the comments and petitions, 
NHTSA has decided to adopt certain limited 
amendments at this time from the November 1982 
NPRM. This action will enable manufacturers to 
appropriately, and in a timely fashion, identify 
their controls and displays while maintaining and 
improving safety by adopting internationally ac- 
cepted symbols for identifying these devices. The 
agency is postponing a final decision on the rest of 
the amendments proposed by the two notices 
pending completion of an ongoing examination by 
the agency of issues related to Standard No. 101. 
This examination is expected to be complete this 
summer. Although this examination will broadly 
cover the requirements of Standard No. 101, it is 
anticipated to result in a Notice of Proposed 
Rulemaking, final action on which will not be 
timely to respond to the immediate needs of the 
manufacturers and the public. Thus, issuance of 
this final rule is necessary at this time. 

The amendments adopted at this time include: 
(1) replacing the symbol specified for headlamp/tail 
lamp controls that are part of master lighting swit- 
ches with the ISO master lighting switch symbol, 
while making the required identification for head- 
lamp/tail lamp controls that are separate from 
master lighting switches at the option of the 
manufacturer, (2) making a minor modification in 
the symbol specified for the clearance lamp system 
control, (3) permitting several symbols to be used 
in solid or outline form, (4) specifying that horn 
controls, with limited exceptions, be identified by 
the ISO horn symbol, (5) permitting heating and air 
conditioning controls to be identified by symbols 
as an alternative to words, with the symbols at the 
option of the manufacturer, and (6) making minor 
interpretive amendments. 

As discussed below, the effective date for certain 
new or changed symbols is September 1, 1987. An 
immediate effective date is established for optional 
use of the new or changed symbols and for the other 
amendments, all of which are of an optional nature. 



The discussion of issues and comments which 
follows is largely limited to those relating to the 
amendments adopted by this notice. Remaining 
issues will be addressed after the agency has com- 
pleted its comprehensive examination of issues 
related to Standard No. 101. 

Symbol Requirements 

The November 1982 notice explained that Stan- 
dard No. 101 specifies the mandatory use of cer- 
tain symbols for the identification of a number of 
controls and displays. Additional words and sym- 
bols are permitted to be used for purposes of in- 
creasing clarity of the identification. (Standard No. 
101 requires several other controls and displays, 
for which symbols are not specified, to be identi- 
fied by words. Also, the use of words instead of 
symbols is permitted in informational readout dis- 
plays.) The symbols specified by the standard are 
those developed by the International Standards 
Organization or similar symbols based on ISO stan- 
dards. In the notice adopting the use of these sym- 
bols (43 FR 27541, June 26, 1978), the agency ex- 
plained that the rationale for requiring symbols 
was that they can convey information more quick- 
ly and with less chance of human error than words. 
The agency noted that this was particularly true 
with respect to the large foreign language speak- 
ing population of this country. The agency also in- 
dicated that an additional benefit was that manu- 
facturers which sell vehicles both in and outside of 
the United States could realize cost savings by 
utilizing internationally acceptable symbols. 

As noted above, the November 1982 notice pro- 
posed to update Standard No. 101 by adding or 
modifying several symbols to bring the standard 
into harmony with the latest documents pro- 
mulgated by the ISO. The agency stated that the 
changes would reduce compliance costs by pro- 
moting international harmonization and would 
result in safety benefits. 

Almost all of the comments supported the con- 
cept of changing Standard No. 101 to facilitate in- 
ternational harmonization. The comments were 
mixed, however, with respect to some of the specific 
proposed amendments, especially to the extent that 
the number of required symbols would be increased. 

While some manufacturers strongly supported 
the amendments essentially as proposed, others 
questioned the underlying safety need for the 
standard's requirement for symbols. Concern was 
expressed by some manufacturers that an increased 



PART 571; SlOl -PRE 12 



number of required symbols could result in 
greater risk of producing non-conforming vehicles, 
with the possibility of having to recall vehicles. 

General Motors expressed concern that either 
requiring an overabundance of symbols, or re- 
quiring symbols that offer no intuitive recogniz- 
ability, would not be in the best interests of its 
customers or the marketability of its products. 
That company stated that while the existing set of 
required symbols does not present a significant 
problem, the addition of more mandatory symbols 
could lead to increased customer resistance and 
driver confusion. On this last point. General 
Motors stated that the symbols most recently 
adopted by the ISO have been adopted without 
testing to assure immediate recognizabUity, with a 
greater probability that the meaning of the sym- 
bols must be learned. 

The agency agrees that too many symbols, or 
symbols that are not easily recognizable, are not in 
the public's or industry's interest. For this reason, 
the agency has postponed action on some of the ad- 
ditional requirements proposed in the November 
1982 notice. These will be addressed in the 
agency's forthcoming evaluating of Standard No. 
101. Thus, this final rule adds one completely new 
symbol (the horn symbol) to the standard and 
changes or modifies several others. The agency 
believes, based on the comments to the docket and 
the work of the ISO, that each of the new and 
modified symbols is easily recognizable. The 
agency also believes that the amendments will not 
create confusion or any other problems related to 
a possible "overabundance" of symbols, because of 
their limited nature. The agency will consider the 
broader issues of possible "overabundance" of 
symbols and of new symbols which may not offer 
intuitive recognizabUity as part of its comprehen- 
sive examination of Standard No. 101 issues. 

Master Lighting Switch Symbol 

As explained in the November 1982 notice, the 
proposal to replace the symbol specified for the 
headlamp/tail lamp control with the master 
lighting symbol resulted in part from a petition for 
rulemaking submitted by Renault. Renault's peti- 
tion had pointed out that the symbol specified by 
Standard No. 101 for that control is different from 
that used elsewhere in the world. That petitioner 
noted that the Standard No. 101 symbol is that 
designated by the ISO for high beam headlamps, 
rather than for the headlamp/tail lamp control. 



Most of the commenters supported changing to 
the master lighting symbol. General Motors stated 
that it supports the proposal to revise the symbols 
for those control and display functions which al- 
ready require identification in order to bring them 
into harmonization with European requirements, 
including replacing the headlamp symbol with the 
master lighting symbol. Several other manufac- 
turer comments specifically supported the change. 

Renault stated that while it approves without 
reservation the introduction of the master lighting 
symbol into the standard, the list of functions cor- 
responding to the symbol given in column 1 of 
Table 1 should be expanded or at best omitted 
altogether. The proposed wording in column 1 
referred to by Renault was "Master Lighting 
Switch, Headlamp and Tail Lamps." 

One commenter, Grumman Flxible, disagreed 
with changing to the master lighting symbol. That 
company argued that the symbol is too ambiguous, 
does not specifically indicate that the lamps it 
represents include headlamps, and also represents 
additional components not specifically indicated. 
Grumman Flxible also argued that the symbol is 
not immediately recognizable, due to both an ini- 
tial unfamiliarity with the symbol in this country 
and because the pictogram is too abstract in 
nature. That commenter also stated that the sym- 
bol does not allow for any distinction between the 
headlamp mode and parking light mode, and that 
that issue should be addressed. Finally, Grumman 
Flxible stated that it finds no evidence that the 
symbol is used by the rest of the world for head- 
lamps and that most foreign vehicles it is famUiar 
with use the current Standard No. 101 headlamp 
symbol. 

Fiat stated that identification for the headlamp 
control has been omitted from Table 1. According 
to that commenter, the headlamp symbol should be 
required for the identification of the high beam/low 
beam switch if this is separate from the master 
lighting switch. 

This notice adopts the master lighting switch 
symbol for headlamp/tail lamp controls that are 
also master lighting switches, i.e., single controls 
that operate several different lamp systems. The 
agency continues to require identification of head- 
lamp/tail lamp controls that are separate from the 
master lighting switch. However, the agency has 
decided that the method of identifying headlamp/ 
tail lamp controls should be at the option of the 
manufacturer. 



PART 571; SlOl- PRE 13 



Standard No. 101 currently specifies the same 
symbol for headlamp/tail lamp controls whether or 
not such controls are also master lighting switches. 
The description of the control designated in col- 
umn 1 of Table 1 is "Headlamps and Tail Lamps." 
A footnote indicates that the symbol must also be 
used when clearance, identification, parking and/or 
side marker lamps are controlled with the head- 
lamp switch. The type of control described by the 
footnote is a master lighting switch. Typical pas- 
senger cars, as well as many other vehicles, have 
master lighting switches instead of separate con- 
trols for various types of lamps. 

The November 1982 notice proposed the use of 
the master lighting switch symbol for both master 
lighting switches and separate headlamp/tail lamp 
controls. The proposed description for column 1 of 
Table 1 referred to by Renault, "Master Lighting 
Switch, Headlamp and Tail Lamps", indicated that 
the symbol was to apply to both types of controls. 
Thus, the words "Headlamp and TaU Lamps" were 
not intended to be a list of functions corresponding 
to the master lighting switch. 

The agency believes that the master lighting 
switch symbol is the most appropriate and easily 
recognizable symbol to identify master lighting 
switches. The agency does not agree with Grum- 
man Flxible that the symbol is not immediately 
recognizable or that the pictogram is too abstract. 
The symbol in question obviously resembles a light 
bulb with lines representing rays of light going out 
in all directions. Since the control operates several 
different lamps, typically including at least head- 
lamps and tail lamps, parking lamps and side 
marker lamps, the agency considers such a general 
lighting symbol to be more appropriate than one 
which more specifically indicates a single par- 
ticular type of lamp, i.e., headlamps. With regard 
to Grumman Flxible's statement that the symbol 
does not allow for any distinction between the 
headlamp mode and parking mode, the agency 
notes that Standard No. 101 permits the use of 
words or symbols in addition to those required, for 
purposes of clarity. Thus, a manufacturer may, but 
is not required to, use such words or symbols to 
distinguish between different modes. 

The agency does not understand Grumman Flxi- 
ble's statement that it finds no evidence that the 
symbol is used by the rest of the world for head- 
lamps and that most foreign vehicles it is familiar 
with use the current Standard No. 101 headlamp 
symbol. The master lighting switch symbol is 



specified by both the ISO and European Economic 
Community and is required for vehicles produced 
for sale in the European market. 

The agency has decided that it would not be ap- 
propriate to require the master lighting switch 
symbol to be used for headlamp/tail lamp controls 
that are separate from a master lighting switch. 
The general master lighting switch symbol could 
be confusing in such instances. For example, a 
driver might see the master lighting switch sym- 
bol and believe that it operated all of the vehicle's 
lamps instead of only the headlamps. Also, iden- 
tification which more specifically indicates head- 
lamps, such as the symbols specified by the ISO, 
might be more appropriate. The agency has de- 
cided that identification should continue to be re- 
quired for a separate headlamp/tail lamp control 
and has therefore included that control in Table 1. 
The agency has decided, however, that the specific 
identification for such a control should be at the op- 
tion of the manufacturer. 

Clearance Lamp Symbol 

The November 1982 notice proposed a minor 
modification in the symbol specified for the 
clearance lamp system control. The notice also pro- 
posed a change in the applicability of the symbol to 
identification lamp and side marker lamp controls. 

The notice explained that there are three very 
similar versions of this symbol. The reason for the 
multiple versions appears to be that the symbol 
was stUl under consideration by the ISO when the 
United States and Europe established their iden- 
tification requirements, and it was not clear which 
specific symbol would be adopted. The agency pro- 
posed in November 1982 deleting the version cur- 
rently included in Standard No. 101 and adopting 
the version finally specified by the ISO in the in- 
terests of cost minimization through harmoniza- 
tion. That is the same version specified by the 
European Economic Community (EEC). The third 
version is specified by the United Nations 
Economic Commission for Europe (ECE). The 
agency explained that, as essentially the same 
symbol, all three versions are equally effective at 
presenting their message. The agency added, how- 
ever, that for purposes of optimal driver recogni- 
tion and cost minimization through international 
harmonization, it believed that it was desirable to 
specify the use of only one of the three versions. 

Several manufacturer commenters agreed that 
the ISO/EEC version should be specified by 



PART 571; SlOl- PRE 14 



Standard No. 101. Some commenters stated that 
the ECE version should not be permitted as an al- 
ternative, since it would be contrary to the antici- 
pated goal of harmonization. It was also pointed 
out that the ECE version is in a draft regulation 
and may not be finally adopted by that organization. 

GM agreed that it is desirable to have one sym- 
bol ultimately prevail and suggested that NHTSA 
work within the ECE to resolve differences. GM 
argued, however, that resolving the differences is 
a harmonization issue rather than a safety issue 
and suggested that all three versions be permitted 
in the meantime. GM commented that all three 
versions are reasonably recognizable and similar 
enough in form that confusion should not result. 
Volkswagen similarly commented that the ver- 
sions are virtually identical. 

While it is true that the three versions are 
similar, the agency believes that for purposes of 
easy recognition only one should be specified. The 
leadtime provided by this notice gives adequate 
time for manufacturers to make the very minor 
changes necessitated by adoption of the ISO ver- 
sion, as proposed. 

Grumman Flxible suggested that the ECE sym- 
bol for parking lights be adopted in place of the 
clearance lamp symbol. (The ECE symbol is the 
same as the ISO symbol.) That commenter ap- 
peared to believe that the clearance lamp symbol 
must be used for the master lighting switch when 
it is adjusted so that all lights except the 
headlamps are on, or for a separate parking light 
control. The clearance lamp symbol need not be 
used in either instance. The clearance lamp symbol 
is only specified for a separate control for iden- 
tification, side marker and/or clearance lamps. As 
indicated above, manufacturers may, but need not, 
supplement the master lighting switch symbol 
with additional symbols to identify the lights 
operated by the different adjustment positions of 
that switch. Thus, a manufacturer could use the 
ISO parking light symbol, not specified by Stan- 
dard No. 101, for a particular position of a master 
lighting switch. Similarly, since Standard No. 101 
does not specify identification for a separate park- 
ing light control, a manufacturer could use the ISO 
parking light symbol to identify such a control. 

As noted above, the agency also proposed a 
change in the applicability of the symbol to iden- 
tification lamp and side marker lamp controls. 
Standard No. 101 currently specifies the symbol 
for clearance lamp controls, with a footnote in 



Table 1 indicating that the symbol should also be 
used when clearance lamps, identification lamps, 
and/or side marker lamps are controlled with one 
switch other than the headlamp switch. No sym- 
bols are specified for identification of separate con- 
trols for identification lamps or side marker lamps. 
The notice proposed that the symbol be specified 
for all controls operating these three types of 
lamps, except for a master lighting switch. This 
notice adopts the amendment as proposed. If 
separate controls are provided for these types of 
lamps, a manufacturer may use additional words 
or symbols for purposes of clarity. 

Shading of Symbols 

Tables 1 and 2 of Standard No. 101 include foot- 
notes that permit framed areas of certain symbols 
to be filled in. Recently, the ISO adopted variants 
of certain other symbols to essentially permit solid 
areas of those symbols to be in outline form. The 
November 1982 notice requested comments on 
whether manufacturers should be permitted to use 
those variant symbols. All of the comments re- 
ceived on this issue supported allowing the variant 
symbols. Some commenters stated that the ISO 
symbols shown in outline form are sufficiently 
recognizable. 

The agency agrees that the outline symbols are 
recognizable. Therefore, this notice permits those 
variant symbols to be used for the heating and/or 
a'T conditioning fan, the seat belt telltale, and fuel 
level. 

Horn Control 

In proposing a requirement that the horn con- 
trol be identified, the November 1982 notice ex- 
plained that NHTSA has received a number of 
complaints over the years about difficulty in 
locating the horn, especially in panic situations. 
The agency noted that since location of the horn is 
not standardized either by industry practice or by 
regulation, identification of the horn can provide 
important safety benefits at a minimal cost. The 
agency proposed that horn controls be identified 
by the ISO horn symbol, which is a picture of a 
horn (or bugle). 

Comments received on this issue were mixed. 
Some manufacturers supported the horn require- 
ment essentially as proposed. Several manufac- 
turers stated that identification is unnecessary 
when the horn is located in the usual place, i.e., on 
or near the steering wheel. Also, as indicated 



PART 571; SlOl- PRE 15 



above, some manufacturers opposed any expan- 
sion of Standard No. lOl's requirements. 

This notice adopts the requirement that the 
horn control be identified by the ISO horn symbol, 
with limited exceptions discussed below. The horn 
is an important device in accident avoidance. Ac- 
cordingly, the agency believes it is esential that 
drivers be able to quickly locate the horn control. 
In adopting this symbol, the agency concludes that 
it is clearly and intuitively recognizable. 

For other than heavy duty vehicles, the agency 
does not agree that identification is unnecessary 
when the horn control is located on or near the 
steering wheel. First, horn control location within 
the steering wheel area may vary significantly 
from vehicle to vehicle, making it difficult to find 
the horn control in an emergency situation. Second, 
to the extent that manufacturers locate the horn 
control elsewhere, e.g., on various stalks, drivers 
are less likely to expect the horn in what was once 
the traditional location. Moreover, the absence of a 
horn symbol in the steering wheel area will alert 
drivers to look elsewhere. Finally, controls other 
than the horn, such as a cruise control, may be 
located on or near the steering wheel, making it 
more difficult to find a horn control in that same 
general area. 

Some commenters expressed concern about how 
Standard No. lOl's requirement that symbols be 
perceptually upright might apply to horn controls 
located on the steering wheel. It was noted that it 
is impossible for these horn symbols to be percep- 
tually upright at all times. In response to these 
comments, the agency has included a provision 
that the horn symbol need be perceptually upright 
only when the vehicle, aligned to the manufac- 
turer's specification, has its wheels positioned for 
the vehicle to travel straight forward, i.e., when 
the steering wheel is centered. 

Volkswagen stated that the horns on some of its 
vehicles are actuated by pressing virtually 
anywhere on a large, cushioned pad extending 
over almost the entire area inside the steering 
wheel. That commenter stated that the proposal 
was unclear where a horn symbol should be placed 
in that situation. The agency does not agree that 
this is unclear. Standard No. 101 generally pro- 
vides that the identification for controls be placed 
on or adjacent to the control. Accordingly, Volks- 
wagen could place a single horn symbol anywhere 
on or adjacent to the cushioned pad. 

The November 1982 notice proposed to exclude 



narrow ring-type horn controls from the identifica- 
tion requirement since there may not be sufficient 
space on or adjacent to such controls for the horn 
symbol. One commenter pointed out that the re- 
quirements of Standard No. 203, Impact protection 
for the driver from the steering control system, 
have largely eliminated that type of control. That 
standard requires that the steering control system 
be constructed so that no components or at- 
tachments, including horn actuating mechanisms, 
can catch the driver's clothing or jewelry during 
normal driving maneuvers. While some ring-type 
horn control designs are prohibited by that re- 
quirement since they can catch the driver's 
clothing or jewelry during normal driving 
maneuvers, other designs do not have that prob- 
lem. The agency has therefore adopted that pro- 
posed exclusion. 

Several manufacturers commented that most 
heavy duty vehicles, unlike passenger cars, have 
both a standard horn and an air horn. The air horn 
is typically activated by pulling on a lanyard, i.e., 
chain, cable or rope, above the driver's head. Ac- 
cording to these commenters, placing a symbol on 
such a device would be difficult due to the small 
area of the lanyard. These commenters also stated 
that identification of such horns is unnecessary 
since professional heavy duty vehicle operators 
are familiar with this type of control. These com- 
menters also argued that the location of the stan- 
dard (electric) horn on these vehicles is stan- 
dardized in the center of the steering wheel hub 
and that identification of these horns is also un- 
necessary. 

The agency agrees with these commenters con- 
cerning air horns and has excluded lanyard- 
operated horns from Standard No. lOl's identifica- 
tion requirements. The agency also agrees with 
the commenters concerning electric horns in 
heavy duty vehicles. Manufacturers of those vehi- 
cles have traditionally placed the electric horn in 
the center of the steering wheel hub and the agen- 
cy therefore sees no need to regulate in this area. 

Heating and Air Conditioning Controls 

Standard No. 101 currently requires identifica- 
tion for each function of any heating and air condi- 
tioning control, and for the extreme positions of 
any such control that regulates a function over a 
quantitative range. If a symbol is not specified by 
the standard for such a function, the identification 
must be in word form (unless color coding is used.) 



PART 571; SlOl -PRE 16 



Standard No. 101 currently specifies symbols for 
several functions of a heating and air conditioning 
system, including the fan, defrosting and defog- 
ging, and rear window defrosting and defogging. 
The November 1982 NPRM proposed to add sev- 
eral ISO symbols to cover additional functions, in- 
cluding heating, air conditioning, various types of 
vents, and heated seat. 

The agency received numerous comments which 
were opposed to adding these symbols to Standard 
No. 101. Some commenters stated that the sym- 
bols in question were inexplicit and had been 
adopted hastily by the ISO, without testing for 
recognizability. According to some commenters, 
there are efforts within the ISO to change the sym- 
bols. Concern was also expressed that the symbols 
are difficult to apply to many of the complex 
heating and air conditioning systems in use today 
or planned for the future. Several manufacturers 
submitted drawings of heating and air condition- 
ing systems to illustrate the problems associated 
with the application of the proposed symbols. GM 
stated that questions of interpretation raise the 
concern that these particular proposed changes 
are not objective, since manufacturers would not 
have the requisite assurance that they have met 
the standard with any specific design. 

Ford requested that controls for automatic 
temperature control systems be exempted from 
the proposed requirements. Other manufacturers 
expressed concern about how to identify controls 
with multiple functions. 

Volkswagen recommended that manufacturers 
be permitted to use words or symbols, of their own 
choosing, for heating and air conditioning controls. 
That company argued that such flexibility would 
result in more meaningful symbols being utilized 
for various functions. Volkswagen acknowledged 
that such flexibility could result in lack of uniform 
use of the same symbol for the same control by all 
manufacturers and in use of symbols not consis- 
tent with international recommendations. That 
commenter did not believe that these would be 
significant problems, however, noting among other 
things that there is so much variety in heating and 
air conditioning systems that each car would still 
be unique, even if the proposed symbols were used. 

This notice adopts an approach along the lines 
suggested by Volkswagen. NHTSA continues to 
believe that, as currently required, each function 
of a heating or air conditioning system should be 
identified. Based on its review of comments, 



tlia 



however, the agency agrees tliat the proposed 
symbols are not adequate for defining the func- 
tions of all heating and air conditioning systems. 
While the agency considered simply maintaining 
the current requirement that words be used for 
functions where symbols are not specified, the 
agency has decided instead that both safety and 
cost reduction through harmonization are best 
served by permitting manufacturers to identify 
such functions by words or symbols, with the 
specific words or symbols at the discretion of the 
manufacturer. 

As discussed above, the agency has previously 
concluded that symbols can convey information 
more quickly and with less chance of human error 
than words, resulting in safety benefits. Use of 
symbols appears to be particularly appropriate for 
identifying some functions of complex heating and 
air conditioning systems. For example, a relatively 
simple symbol can convey information about such 
things as the direction of air flow more readily and 
clearly than words. 

The agency continues to believe that, for pur- 
poses of optimum recognizability, standardized in- 
ternational symbols should be used wherever 
possible. In the case of symbols for some functions 
of heating and air conditioning systems, however, 
where the agency has concluded that standardized 
symbols are not fully or adequately developed, the 
agency considers it appropriate to permit manu- 
facturers to use symbols of their own choosing. 
This action may not only result in safety benefits, 
as manufacturers develop and use symbols for 
these functions, but also promotes harmonization. 
Manufacturers which produce vehicles for sale in 
non-English-speaking countries using symbols will 
not need to develop special designs using English 
words. 

The agency will monitor the continued develop- 
ment of international symbols in this area, as well 
as the symbols actually used by manufacturers on 
their vehicles' heating and air conditioning 
systems. If circumstances should warrant, the 
agency may consider specifying standardized sym- 
bols in the future. 

The agency declines to exempt automatic tem- 
perature control systems from the standard's iden- 
tification requirements. The need for identification 
of controls for this type of system is no different 
than for traditional heating and air conditioning 
systems. However, the option of using words or 
symbols of the manufacturer's choosing should 



PART 571; SlOl -PRE 17 



provide ample flexibility in identifying the con- 
trols of these systems. 

Manufacturers will continue to be required to 
use the symbols specified by Standard No. 101 for 
the fan, windshield defrosting and defogging, and 
rear window defrosting and defogging. The option 
of using words or symbols of the manufacturer's 
choosing applies only to other functions. The addi- 
tion of this option does not impose any new 
requirements since manufacturers are already re- 
quired to identify those other functions by words. 

Interpretive Amendments 

This notice adopts several interpretive amend- 
ments, as proposed by the November 1982 notice 
and in accord with previous agency interpreta- 
tions. Two footnotes concerning the turn signal 
control symbol are added to Table 1. That symbol, 
a pair of horizontal arrows pointing to the left and 
right, is ordinarily a single symbol. One footnote 
makes it clear that the two arrows may be consi- 
dered separate symbols where there are indepen- 
dent controls for the left and right turn signals. 
The other footnote makes it clear that framed 
areas of that symbol or symbols may be filled in. 

Section S5.3.5 of Standard No. 105 is amended to 
indicate that the words "Brake Fluid" need not be 
used for a separate indicator lamp for brake fluid 
where a vehicle uses hydraulic system mineral oil 
rather than conventional brake fluid. (A manufac- 
turer is instead required to use the word "Brake" 
and appropriate additional labeling.) 

This notice also makes related interpretive 
amendments of a minor nature in section S5.3.5 of 
Standard No. 105 and Table 2 of Standard No. 101 
that were not proposed by the November 1982 
notice. Section S5.3.5 currently requires that a 
malfunction in an anti lock system be identified by 
the word "Antilock". Table 2 specifies the same 
word but in a hyphenated form, i.e., "Anti-Lock." 
This notice amends the two standards to make it 
clear that a manufacturer may use either form of 
the word. Since these amendments are interpre- 
tive, notice and comment is not required. 

The November 1982 notice also proposed other 
changes in section S5.3.5 of Standard No. 105. 
WhUe the agency is not adopting any other 
substantive changes in that section at this time, it 
is adopting a new format for that section along the 
lines proposed by that notice. 

The November 1982 notice proposed to drop the 
words listed by column 2 of Table 1 for controls for 



which a symbol is also specified. Section S5.2.1(a) 
provides that while the symbol specified by Table 
1 for such a control is mandatory, the words listed 
by column 2 may be used in addition to the symbol. 
That same section provides further, however, that 
any additional words or symbols may be used at 
the manufacturer's discretion for purposes of clari- 
ty. Since manufacturers may use any words in ad- 
dition to the required symbol, the provision that a 
manufacturer may use the words specified by col- 
umn 2 has no legal effect. Accordingly, this notice 
drops those words from column 2 and makes a con- 
forming amendment to section S5.2.1(a). 

Leadtime 

The amendments are effective immediately. 
However, some amendments are of an optional 
nature until September 1, 1987. The agency finds 
good cause for an immediate effective date for the 
optional identification requirements since the 
amendments relieve restrictions, while reducing 
compliance costs and promoting safety. 

The November 1982 notice proposed an effec- 
tive date of September 1, 1985, for mandatory use 
of the new symbols. Several commenters sug- 
gested that date was too early. In promulgating 
this final rule, the agency has determined that a 
date of September 1, 1987 provides adequate lead- 
time. The agency also finds it is in the public in- 
terest to establish such a relatively long leadtime 
for mandatory use of the new symbols, given the 
nature of the changes and since such a leadtime 
minimizes compliance costs. 

In consideration of the foregoing, §571.101 and 
§571.105, Chapter V of Title 49, Code of Federal 
Regulations, are amended as follows: 

%571. 101 [Amended] 

1. Section S5 is revised to read as follows: 

S5. Requirements, (a) Except as provided in 
paragraph (b) of this section, each passenger car, 
multipurpose passenger vehicle, truck and bus 
manufactured with any control listed in S5.1 or in 
column 1 of Table 1, and each passenger car, multi- 
purpose passenger vehicle and truck or bus less 
than 10,000 pounds GVWR with any display listed 
in S5.1 or in column 1 of Table 2, shall meet the re- 
quirements of this standard for the location, identi- 
fication, and illumination of such control or display. 

(b) For vehicles manufactured before Septem- 
ber 1, 1987, a manufacturer may, at its option — 

(1) Meet the requirements in this standard to use 
identifying words or abbreviation or identifying 



PART 571; SlOl-PRE 18 



symbol for a control by using those specified in 
Table 1(a) instead of Table 1. If none are specified 
in Table 1(a), none need be used for the control. 

(2) Meet the requirements in this standard to 
use identifying words or abbreviation or identify- 
ing symbol for a display by using those specified in 
Table 2(a) instead of Table 2. If none are specified 
in Table 2(a), none need be used for the display. 

2. Section S5.2.1(a) is revised to read as follows: 
(a) Except as specified in S5.2.1(b), any hand- 
operated control listed in column 1 of Table 1 that 
has a symbol designated in column 3 shall be iden- 
tified by that symbol. Any such control for which 
no symbol is shown in Table 1 shall be identified by 
the word or abbreviation shown in column 2, if 
such word or abbreviation is shown. Words or 
symbols in addition to the required symbol, word 
or abbreviation may be used at the manufacturer's 
discretion for the purpose of clarity. Any such con- 
trol for which column 2 of Table 1 and/or column 3 
of Table 1 specifies "Mfr. Option" shall be iden- 
tified by the manufacturer's choice of a symbol, 
word or abbreviation, as indicated by that speci- 
fication in column 2 and/or column 3. The iden- 
tification shall be placed on or adjacent to the con- 
trol. The identification shall, under the conditions 
of S6, be visible to the driver and, except as pro- 
vided in S5.2.1.1 and S5.2.1.2, appear to the driver 
perceptually upright. 

3. Section S5.2.1.1 is revised to read as follows: 
S5.2.1.1 The identification of a master lighting 

switch or headlamp and tail lamp control that ad- 
justs control and display illumination by means of 
rotation, or of any other rotating control that does 
not have an off position, need not appear to the 
driver perceptually upright. The identification of a 
horn control need not appear to the driver percep- 
tually upright except when the vehicle, aligned to 
the manufacturer's specifications, has its wheels 
positioned for the vehicle to travel in a straight 
forward direction. 

4. The second sentence of section S5.2.2 is re- 
vised to read as follows: 

If this identification is not specified in Tables 1 
or 2, it shall be in word or symbol form unless color 
coding is used. 

5. A new Table 1 is added following section 86 
to read as set forth below. 

6. The existing Table 1 is redesignated Table 
1(a). 

7. A new Table 2 is added following Table 1(a) to 
read as set forth below. 



8. The existing Table 2 is redesignated Table 
2(a). 

%571. 105 [Amended] 

1. Section S5.3.5 is revised to read as follows: 

S5.3.5(a) Each indicator lamp shall display word 
or words, in accordance with the requirements of 
Standard No. 101 (49 CFR 571.101) and/or this sec- 
tion, which shall be legible to the driver in daylight 
when lighted. The words shall have letters not less 
than 1/8-inch high. Words in addition to those re- 
quired by Standard No. 101 and/or this section and 
symbols may be provided for purposes of clarity. 

(b) If a single common indicator is used, the 
lamp shall display the word "Brake". The letters 
and background of a single common indicator shall 
be of contrasting colors, one of which is red. 

(c)(1) If separate indicator lamps are used for 
one or more than one of the functions described in 
S5.3.1(a) through S5.3.1(d), the display shall, except 
as provided in (c)(1)(A) through (D) of this section, 
include the word "Brake" and appropriate addi- 
tional labeling. 

(A) If a separate indicator lamp is provided for 
gross loss of pressure, the words "Brake Pressure" 
shall be used for S5.3.1(a). 

(B) If a separate indicator lamp is provided for 
low brake fluid, the words "Brake Fluid" shall be 
used for S5.3.1(b), except for vehicles using 
hydraulic system mineral oil. 

(C) If a separate indicator lamp is provided for 
an anti lock system, the single word "Antilock" or 
"Anti-Lock" may be used for S5.3.1(c). 

(D) If a separate indicator lamp is provided for 
application of the parking brake, the single word 
"Park" may be used for S5.3.1(d). 

(2) Except for a separate indicator lamp for an 
antilock system, the letters and background of 
each separate indicator lamp shall be of con- 
trasting colors, one of which is red. The letters and 
background of a separate indicator lamp for an 
anti lock system shall be of contrasting colors, one 
of which is yellow. 

Issued on July 24, 1984 



Diane K. Steed 
Administrator 

49 FR 30191 
July 27, 1984 



PART 571; SlOl-PRE 19 



Table 1 
Identification and Illumination of Controls 



Column 1 


Column 7 


Column 3 


Column 4 


Hand Operated Controls 


Identifying Words 
or Abbreviation 


Identifying 
Symbol 


Illumination 


• 
Master Lighting 
Switch 




■Vr 








Headlamps and 
Tail lamps 


(Mfr Option)' 


(Mfr Option)' 






Horn 




►o- ' 








Turn Signal 












Hazard Warning 
Signal 




A' 


Yes 




Windshield Wiping 
System 




V 


Yes 




Windshield Washing 
System 




<J> 


Yes 




Windshield Washing 
and Wiping Combined 






Yes 




Heating and or Air 
Conditioning Fan 




9S.S8 


Yes 




Windshield Defrosting 
and Defogging System 




<^ 


Yes 




Rear Window Defrosting 
and Defogging System 






Yes 


M- 




))) 


Identification, Side 

Marker and or Clearance 

Lamps 




-00- 


Yes 




Manual Choke 


Choke 










Engine Start 


Engine Start^ 










Engine Stop 


Engine Stop^ 




Yes 




Hand Throttle 


Throttle 










Automatic Vehicle Speed 


(Mfr Option) 




Yes 




Heating and Air 

Conditioning 

System 


(Mfr Option) 


(Mfr Option) 


Yes 



■' Use when engine control is separate from the key locking system 

' Separate identification not required if controlled by master lighting switch. 

' The pair of arrows is a single symbol When the controls for left and right turn operate independently, 

however, the two arrows may be considered separate symbols and be spaced accordingly 
* Identification not required for vehicles with a GVWR greater than 10,000 lbs., or for narrow ring-type controli. 
' Framed areas may be filled. 

PART 571; SlOl- PRE 20 



Table 2 



Identification and Illumination of Displays 



Column 1 


Column 2 


Column 3 


Column 4 


Column 5 


Display 

• 


Telltale 
Color 


Identifying Words 
or Abbreviation 


Identifying 
Symbol 


illumination 


Turn Signal 
Telltale 


Green 


Also see 
FMVSS 108 


<p^: 




Hazard Warning 
Telltale 


Red" 


Also see 
FMVSS 108 


a: 




Seat 

Belt 

Telltale 


Red" 


Also see 
FMVSS 208 


^rr o< ^o^ 




Fuel Level 
Telltale 


Yellow 


Fuel 


».B 


Yes 


Gauge 




Oil Pressure 
Telltale 


Red" 


Oil 


*£/; 


Yes 


Gauge 




Coolant Temperature 
Telltale 


Red" 


Temp 


J. 


Yes 


Gauge 






Electrical Charge 
Telltale 


Red" 


Votts, Charge 
or Amp 


n 


Yes 


Gauge 






Highbeam 
Telltale 


Blue or 
Green" 


Also see 
FMVSS 108 


ID^ 




Malfunction in 
Anti-Lock or 


Yellow 


Antilock or Anti-lock 
Also see FMVSS 105 






Brake System 


Red" 


Brake. Also 
see FMVSS 105 






Brake Air Pressure 
Position Telltale 


Red" 


Brake Air. Also 
see FMVSS 121 






Speedometer 




MPH^ 




Yes 


Odometer 




3 






Automatic Gear 
Position 




Also see 
FMVSS 102 




Yes 



The pair of arrows is a single symbol. When the indicator for left and right turn operate independently, however, the two arrows 
will be considered separate symbols and may be spaced accordingly. 

Not required when arrows of turn signal tell-tales that otherwise operate independently flash simultaneously as hazard warning 
tell-tale. 

If the odometer indicates kilometers, then "KILOMETERS" or "km" shall appear, otherwise, no Identification is required. 
Red can be red-orange. Blue can be blue-green. 

If the speedometer is graduated in miles per hour and in kilometers per hour, the identifying words or abbreviations shall be 
"MPH and km/h" in any combination of upper or lower case letters. 
* Framed areas may be filled. 

PART 571; SlOl-PRE 21-22 



PREAMBLE TO AN AMENDMENT TO 
FEDERAL MOTOR VEHICLE SAFETY STANDARD NO. 101 

Federal Motor Vehicle Safety Standards 
Controls and Displays 

[Docket No. 1-18, Notice 26; and Docket No. 74-14, Notice 40] 



ACTION: Final rule; response to petitions for 
reconsideration and petitions for rulemaking. 

SUMMARY: This notice responds to three petitions 
for reconsideration and two related petitions for 
rulemaking concerning an amendment to Standard 
No. 101, Controls and Displays, published in July 
1984. That notice amended several of the identifica- 
tion requirements of the standard for the purposes of 
improving safety by providing for the use of easily 
recognizable international symbols and relieving un- 
necessary restrictions on manufacturers by providing 
additional flexibility in their ability to identify controls 
and displays. In response to one of the petitions, the 
agency has eliminated a requirement that the horn 
control symbol be perceptually upright. In response 
to another petition, the agency is permitting use of 
the words "FASTEN BELTS" or "FASTEN SEAT 
BELTS" as an alternative to the seat belt warning sym- 
bol in informational readout displays. A conforming 
amendment is being made to Standard No. 208, Oc- 
cupant Crash Protection. The petitions are otherwise 
denied. However, in the near future, the agency 
plans to publish a separate notice of proposed 
rulemaking which will fully address the issue of the 
use of telltales in informational readout displays, one 
of the major issues raised by one of the petitions for 
reconsideration. 



EFFECTIVE DATE: June 4, 1985. 

SUPPLEMENTARY INFORMATION: On July 27, 
1984, NHTSA published in the Federal Register 
149 FR 30191) a final rule amending Standard No. 
101, Controls and Displays. The notice amended 
several of the identification requirements of the 
standard for the purposes of improving safety by 
providing for the use of easily recognizable, inter- 



national symbols and relieving unnecessary 
restrictions on manufacturers by providmg addi- 
tional flexibility in their ability to identify controls 
and displays. 

The final rule followed two notices of proposed 
rulemaking (NPRM's) to amend Standard No. 101. 
As discussed in the July 1984 notice, the final rule 
did not address all of the amendments proposed by 
the two notices. The notice explained that the 
agency was postponing a final decision on some of 
the proposed amendments pending completion of 
an ongoing examination by the agency of issues 
relating to Standard No. 101. The notice stated 
that the agency's examination of the standard was 
expected to result in a new notice of proposed 
rulemaking. 

The agency received three timely petitions for 
reconsideration of the final rule. The petitions re- 
quested changes in the requirement that the horn 
control on passenger cars and other vehicles with a 
gross vehicle weight rating (GVWR) of 10,000 
pounds or less be identified by the International 
Standards Organization (ISO) horn symbol. Some 
of the petitions also requested that the agency 
adopt some of the amendments that were proposed 
by the two NPRM's but not adopted or addressed 
in the July 1984 final rule, rather than waiting for 
the completion of the agency's examination of 
issues relating to Standard No. 101. 

The agency also received two petitions for recon- 
sideration of the final rule, after the closing date 
for such petitions. Under the agency's procedural 
rules, such petitions are considered petitions for 
rulemaking rather than petitions for reconsidera- 
tion. See 49 CFR SECT. 553.35(a). 

This notice responds to all five petitions. The 
notice will first address the issues raised by the 
petitions for reconsideration with respect to the 
horn control identification requirement. It will 



PART 571; SlOl-PRE 23 



then consider the requests to adopt at this time 
some of the additional proposals on which action 
has been deferred. Finally, the notice will address 
the two petitions for rulemaking. 

Horn Control 

The July 1984 final rule requires that the horn 
control on passenger cars and other vehicles with a 
GVWR of 10,000 pounds or less be identified by the 
ISO horn symbol, a picture of a horn or bugle. The 
agency noted that it has received a number of com- 
plaints over the years about difficulty in locating 
the horn, especially in panic situations. The agen- 
cy noted that since location of the horn is not stan- 
dardized either by industry practice or by regula- 
tion, identification of the horn can provide impor- 
tant safety benefits at a minimal cost. 

As with the identification required for most other 
controls, the rule specified that the horn symbol must 
be perceptually upright. In response to comments on 
the NPRM that it is impossible for symbols on the 
steering wheel to be perceptually upright at all times, 
the agency included a provision that the horn symbol 
need be perceptually upright only when the vehicle, 
aligned to the manufacturer's specification, has its 
wheels positioned for the vehicle to travel forward, 
i.e., when the steering wheel is centered. The rule ex- 
cluded narrow ring-type horn controls from the iden- 
tification requirement since there may not be suffi- 
cient space on or adjacent to such controls for the 
horn symbol. 

A petition for reconsideration submitted by 
Toyota requested that the agency eliminate the 
perceptually upright requirement for the horn con- 
trol symbol. The petitioner argued that the provi- 
sion for a horn control symbol, without the percep- 
tually upright requirement, would accomplish the 
agency's intentions for accident avoidance. That 
company also stated that it is difficult to place a 
perceptually upright symbol on the type of narrow 
button that is typically used on a vertical spoke of 
a steering wheel hub. Toyota noted that while the 
symbol could be located adjacent to the control in 
such a situation, the cost would be three times 
more than if the symbol were simply located on the 
button. 

After carefully evaluating Toyota's arguments, the 
agency has decided to drop the perceptually upright 
requirement for the horn control symbol. This deci- 
sion was based on two considerations. First, unlike 
some symbols which must be properly oriented in 
order to be understood, the horn symbol is readily 
recognizable in any orientation. Second, a horn sym- 
bol may be printed larger and therefore be more easi- 



ly perceived if it can be oriented along the longer axis 
of the horn button, spoke of the wheel, or along the 
rim of the steering wheel. 

A petition for reconsideration submitted by 
Mercedes-Benz requested that the agency exclude 
passenger car horn controls located in/on the steer- 
ing wheel hub from the identification requirement, 
provided that the horn control can be activated by 
pressing anywhere on the hub surface, and that 
there are no other controls incorporated in the hub. 
The petitioner argued that complaints about dif- 
ficulty in finding the horn control must be at- 
tributed to controls located on stalks or other areas 
of the steering column rather than in the usual 
and conventional location in the steering wheel 
hub. Mercedes argued that the location in the 
steering wheel hub is the most obvious and the 
nearest and quickest to reach and to activate in an 
emergency situation, and that even a driver who is 
not familiar with a car will intuitively expect the 
horn control to be in the hub and check there first. 
After carefully evaluating Mercedes' arguments, 
the agency declines to grant that company's re- 
quest. The preamble to the final rule raised many 
concerns that are not answered by Mercedes' 
amendment: 

For other than heavy duty vehicles, the agency 
does not agree that identification is unneces- 
sary when the horn control is located on or 
near the steering wheel. First, horn control 
location within the steering wheel area may 
vary significantly from vehicle to vehicle, mak- 
ing it difficult to find the horn control in an 
emergency situation. Second, to the extent that 
manufacturers locate the horn control else- 
where, e.g., on various stalks, drivers are less 
likely to expect the horn in what was once the 
traditional location. Moreover, the absence of a 
horn symbol in the steering wheel area will 
alert drivers to look elsewhere. Finally, con- 
trols other than the horn, such as a cruise con- 
trol, may be located on or near the steering 
wheel, making it more difficult to find a horn 
control in that same general area. 
The primary concern is that as manufacturers 
place horn controls in areas other than what was 
once the traditional location, drivers' expectations 
as to location also change. For example, a driver 
whose last car had the horn control on the stalk 
may check that location first when driving an un- 
familiar car. Younger drivers may never have en- 
countered a horn control on the steering wheel 
hub. Also, in the absence of a horn symbol at the 



PART 571; SlOl-PRE 24 



steering wheel center, drivers may decide they 
should look elsewhere for the horn control rather 
than trying to activate a nonexistent control. 

Suggestions for Additional Amendments 

Two petitions for reconsideration requested that 
the agency adopt certain amendments to Standard 
No. 101 at this time, rather than awaiting comple- 
tion of its examination of issues relating to the 
standard. A petition submitted by BMW requested 
three amendments: (1) adopt proposed language to 
permit the use of telltales in informational readout 
displays, (2) permit, as proposed, the use of the 
words "FASTEN BELTS" or "FASTEN SEAT 
BELTS" as an alternative to the seat belt warning 
symbol in informational readout displays, and (3) 
permit sequencing of messages in informational 
readout displays in the event of a need to display 
more than one telltale at the same time. Mercedes- 
Benz requested that the agency (1) permit, as pro- 
posed, use of the ISO brake failure symbol instead 
of the word "BRAKE" for brake displays, and (2) 
permit use of the ISO antilock symbol instead of 
the words "ANTILOCK" or "ANTI-LOCK" in 
vehicles having separate indicator lamps for that 
function. 

The amendments requested by BMW all relate to 
the issue of placing telltales in informational 
readout displays. As discussed below, the agency 
has decided not to adopt the specific amendments 
previously proposed on this subject. This decision 
is largely based on the agency's analysis of com- 
ments provided by a number of manufacturers. 
The forthcoming separate NPRM will address the 
problems identified by the commenters. 

The agency has also decided to adopt a final rule 
to permit, as proposed, the use of the words 
"FASTEN BELTS" or "FASTEN SEAT BELTS" 
as an alternative to the seat belt warning symbol 
in informational readout displays. The agency has 
decided not to adopt the other amendments re- 
quested by the BMW and Mercedes petitions. 
These decisions are also discussed below. 

Standard No. lOl's light intensity requirements 
for displays differ depending upon whether the 
display is a gauge or a telltale and whether the 
display is an informational readout display. i The 
background for this latter distinction is as follows. 
The 1976 NPRM for the current version of Stan- 
dard No. 101 did not distinguish between tradi- 
tional displays and informational readout 
displays. That NPRM proposed the following re- 
quirements for all displays: ( 1 ) Light intensities for 
gauges and their identification must be con- 



tinuously variable from a position at which either 
there is no light emitted or the light is barely 
discernible to a driver who has adapted to dark 
ambient roadway conditions to a position pro- 
viding illumination sufficient for the driver to 
identify the display readily under all daytime and 
nighttime conditions, and (2) The light intensity of 
each telltale shall not be variable and shall be such 
that, when activated, that telltale and its iden- 
tification are visible to the driver under all 
daytime and nighttime conditions. See 41 FR 
46460-46462. 

The 1978 final rule adopted by the agency in- 
cluded language very similar to the proposed 
language in these areas. However, that final rule 
also added the term "informational readout 
display" and specified a number of requirements 
for informational readout displays. Among other 
things, the final rule included a requirement that 
informational readout displays must have at least 
two light intensity levels, a higher one for daytime 
use and a lower one for nighttime use. While the 
preamble did not discuss the light intensity re- 
quirements for informational readout displays, the 
preamble did explain that the agency was adop- 
ting a requirement to allow the use of words or 
symbols to permit the continued development of 
informational readout displays. See 43 FR 
27541-27544. 

Subsequent to that 1978 final rule, the agency 
received a petition for rulemaking from General 
Motors to permit incorporation of telltales in infor- 
mational readout displays. In response to that peti- 
tion, the agency published an NPRM in the Feder- 
al Register (47 FR 4541) on February 1, 1982. As 
discussed by that notice, section S5.3.3 of Standard 
No. 101 requires that the light intensity of 
telltales be invariable and must be sufficient to 
permit drivers to see them under any lighting con- 
ditions. The purpose of that requirement is to en- 
sure that telltales are visible to the driver at all 
times when the vehicle is being operated. The 
same section, however, requires that informa- 



'By way of background information, the term "display" in Stan- 
dard No 101 refers to gauges and telltales "Telltale" is defined 
as a display that indicates, by means of a light-emitting signal, 
the actuation of a device, a correct or defective condition, or a 
failure to function. The term "gauge" is defined as a display 
listed in the standard (S5.1 or Table 1) that is not a telltale. All 
displays in Standard No. 101 are thus gauges or telltales. Infor- 
mational readout displays are a type of display which use tech- 
nologies such as light-emitting diodes or liquid crystals, and 
which may display one or more than one type of information or 
message. As a type of display, the term informational readout 
display necessarily refers to gauges and/or telltales. 



PART 571; SlOl-PRE 25 



tional readout displays have variable light intensi- 
ty. Specifically, they must have at least two light 
intensity values, a relatively high one for daytime 
use and a relatively low one for nighttime use. The 
notice concluded that even though other parts of 
th^ standard were written to encourage the use of 
informational readout displays, the standard's 
light intensity requirements prevent informa- 
tional readout displays from being used for 
telltales. 

In order to resolve the discrepancy and permit 
the use of telltales in informational readout 
displays, the agency proposed the following re- 
quirement; 

Telltales and gauges incorporated into informa- 
tional readout displays- 
la) Shall have not less than two levels of light in- 
tensity, a higher one for day and a lower one for 
nighttime conditions. 

(b) In the case of telltales and gauges not 
equipped with a variable light intensity control, 
shall have a light intensity at the higher level pro- 
vided under paragraph (a) of this section whenever 
the headlamps are not illuminated. 

(c) In the case of telltales and gauges equipped 
with a variable light intensity control, shall be 
visible to the driver under all daytime and night- 
time conditions when the illumination level is set 
to its lowest level. 

Two comments received in response to the 
February 1982 notice questioned the conclusion 
that the standard's light intensity requirements 
prevent informational readout displays from being 
used for telltales. Ford commented that it has in- 
terpreted the standard to permit the use of tell- 
tales with single intensity illumination, as re- 
quired for all telltales by section S5.3.3, when in- 
corporated into informational readout displays. 
VDO-ARGO simply stated that it does not believe 
that the current regulations preclude the installa- 
tion of telltales within an informational readout 
display. 

Commenters expressed a number of concerns 
about the specific proposal. Some of these related 
to the proposed requirement that telltales and 
gauges incorporated into informational readout 
displays be visible to the driver under all daytime 
and nighttime conditions when the illumination 
level is set to its lowest level. Chrysler stated that 
its experience indicates that any illumination 



level which is bright enough to be visible to the 
driver during the day would be so bright at night 
that it would be unacceptable to most drivers and 
may be a safety hazard. That company's comments 
indicated that, because of this problem, it may be 
impossible for manufacturers to meet a require- 
ment that telltales and gauges in informational 
readout displays always be visible. 

According to Chrysler, it is current practice to 
provide two levels of illumination by means of the 
headlamp switch, headlamps off— daytime level, 
headlamps on— nighttime level. A limitation of 
this arrangement, however, is that the display il- 
lumination is switched from the daytime to the 
nighttime level whenever the headlamps are turn- 
ed on, regardless of ambient lighting conditions. 
Thus, the minimum level of display illumination 
intensity for night driving is established during 
daytime conditions with headlamps on, with the 
result that the display may not be visible to the 
driver. According to Chrysler, driving with 
headlamps on is not an infrequent occurrence, 
even in the presence of bright sunlight. That com- 
menter noted that while it might be possible to in- 
corporate a photosensitive device to reliably sense 
daytime and nighttime conditions, neither it, nor 
to its knowledge any other company, had been able 
to develop a device which will function properly 
under all conditions. Similar comments were also 
received from other manufacturers. 

Ford expressed concern that the proposed 
language would cause changes in the Ford elec- 
tronic instrument panels now in production for 
three model years by prohibiting single high inten- 
sity electronic telltales. (As noted above. Ford has 
assumed that the standard permits the use of 
telltales with single intensity illumination when 
incorporated into informational readout displays.) 
Volkswagen also expressed concern that single in- 
tensity telltales would be prohibited. That com- 
pany stated that some emergency warning 
telltales should be sufficiently obvious and blatant 
to immediately attract the driver's attention, 
which is best accomplished by single intensity 
telltales. 

After carefully considering the comments, the 
agency has decided not to adopt the requirements 
as proposed. The agency agrees that single intensi- 
ty telltales should not be prohibited in informa- 
tional readout displays, since such telltales may be 
optimally effective for attracting attention. The 
agency recognizes the problems cited by Chrysler 
concerning the proposed requirement that gauges 
and telltales incorporated into informational 



PART 571; SlOl-PRE 26 



readout displays be visible under all daytime and 
nighttime driving conditions. A requirement that 
gauges and telltales be visible under all lighting 
conditions when the light intensity is set at its 
lowest level could result in problems of glare at 
night, particularly for gauges, since they are or- 
dinarily activated. On the other hand, the agency 
is concerned, in the absence of such a requirement, 
about the possibility of drivers inadvertently turn- 
ing off important safety telltales, such as the brake 
warning telltale, by driving with headlamps on 
during the daytime. 

The agency tentatively agrees in a general way 
with the view expressed by some commenters that 
greater flexibility for manufacturers is appropri- 
ate in this area. This issue will be addressed by the 
forthcoming separate NPRM. 

As noted above, some manufacturers have inter- 
preted Standard No. lOl's light intensity re- 
quirements for telltales and gauges incorporated 
into informational readout displays differently 
than the agency and have produced vehicles for 
several years with informational readout displays 
which incorporate telltales. Ford, for example, has 
interpreted the standard to permit the use of 
telltales with single intensity illumination when 
incorporated into informational readout displays. 
Until the agency has completed the rulemaking 
action which is the subject of the forthcoming 
separate NPRM, it will not take any enforcement 
action against manufacturers under section S5.3.3 
of Standard No. 101 on the basis of whether the 
light intensity of informational readout displays, 
including telltales and/or gauges incorporated into 
informational readout is invariable or variable. 
The agency will continue to enforce the require- 
ment that, when activated, telltales and their iden- 
tification be visible to the driver under all daytime 
and nighttime conditions, as well as all other re- 
quirements of the standard. 

As indicated above, BMW's petition requested 
that the agency permit, as proposed by the 
February 1982 NPRM, the use of the words 
"FASTEN BELTS" or "FASTEN SEAT BELTS" 
as an alternative to the seat belt warning symbol 
in informational readout displays. The NPRM ex- 
plained that Standard No. 101 was expressly writ- 
ten to permit words in place of symbols in informa- 
tional readout displays. Section S5.2.3 of the stan- 
dard states that informational readout displays 
may be identified by the symbol designated in col- 
umn 4 of Table 2 or by the word or abbreviation 
shown in column 3. While column 4 of Table 2 
designates the seat belt warning symbol, column 3 



of the table refers to FMVSS 208. That standard 
only permits the use of the words "FASTEN 
BELTS" or "FASTEN SEAT BELTS" for vehicles 
manufactured before September 1, 1980. The 
NPRM stated that a conforming amendment was 
being proposed to correct that anomaly and permit 
those words to be used for the seat belt telltale in- 
corporated in an informational readout display. 

Commenters generally supported this proposal. 
While the issue of the circumstances under which 
telltales may be incorporated into informational 
readout displays will remain unresolved until the 
agency completes the rulemaking action noted 
above, the agency considers it appropriate to make 
this amendment at this time. The agency has 
determined that the standard should permit 
specified words to be used in place of the seatbelt 
warning symbol, in informational readout 
displays. The agency is accordingly adopting the 
proposal as a final rule at this time. 

In its petition for reconsideration and a related 
request for interpretation, BMW expressed con- 
cern at Standard No. lOl's requirements for infor- 
mational readout displays where more than one 
telltale occupies the same space. This concern 
arises from the fact that if the underlying condi- 
tions for activation of more than one such telltale 
occur at the same time, information for messages 
beyond the first can be provided to drivers only if 
some method of either sequencing messages or 
cancelling earlier messages is provided. BMW's 
petition for reconsideration requested that sequen- 
cing of messages be permitted in circumstances 
where there is a need to display more than one 
telltale at the same time. BMW's request for inter- 
pretation asked whether the standard already per- 
mits such sequencing of telltales. That company 
also requested clarification of an earlier inter- 
pretation issued by the agency. BMW noted that 
the agency has concluded that telltales cannot be 
cancelable since Standard No. 101 requires that (1) 
they must be visible to the driver under all 
daytime and nighttime conditions, and (2) they 
must not be variable in light intensity. BMW 
asked whether that requirement applies to all 
telltales or just those listed in the standard. 

Standard No. lOl's requirements for displays are 
only applicable to the displays listed in the stan- 
dard. Section S5, Requirements, states that ". . . 
each passenger car, multipurpose passenger vehi- 
cle and truck or bus less than 10,000 pounds 
GVWR with any display listed in S5.1 or in column 
1 of Table 2, shall meet the requirements of this 
standard for the location, identification, and il- 



PART571;S101-PRE27 



lumination of such . . . display." (Emphasis added.) 
Telltales are a type of display. The requirements of 
Standard No. 101 which prevent telltales from be- 
ing cancelable are thus only applicable to telltales 
listed in the standard. Accordingly, Standard No. 
101 does not prohibit telltales not listed in the 
standard from being cancelable. 

BMW's question concerning whether Standard 
No. 101 permits sequencing of telltales is germane 
only if using informational readout displays as 
telltales is itself permissible since the sequencing 
of telltales in the same spot in a display necessi- 
tates application of that type of technology. The 
previously discussed enforcement policy permit- 
ting the use of informational readout displays as 
telltales makes that question now germane. There 
is no requirement in Standard No. 101, other than 
those relating to the use of informational readout 
displays as telltales, that precludes sequencing. 
Therefore, designs which use sequencing telltales 
in informational readout displays may be used for 
the duration of that enforcement policy. 

The agency emphasizes, however, that its con- 
sideration of sequencing for the first time in the 
context of a rulemaking proceeding, i.e., the pro- 
ceeding relevant to the separate forthcoming 
NPRM, has led to the identification of various safe- 
ty concerns about that design. Those concerns will 
be discussed in that proposal. 

As indicated above, Mercedes-Benz requested 
that the agency permit, as proposed, use of the ISO 
brake failure symbol instead of the word 
"BRAKE" for brake displays. The agency proposed 
adoption of this symbol in an NPRM published in 
the Federal Register (47 PR 49999) on November 
4, 1982. 

The notice explained that the requirements for a 
brake display are primarily included in Standard 
No. 105, Hydraulic Brake Systems, which is 
referenced by Standard 101. Under Standard No. 
105, a manufacturer must provide a brake warn- 
ing indicator lamp which activates under certain 
conditions, including (among others) specified 
types of gross loss of pressure and on application of 
the parking brake. The requirements may be met 
by a single common indicator lamp with a lens 
labeled "Brake", or by separate indicator lamps. 
Separate labeling requirements are provided for 
separate indicator lamps. 

In proposing adoption of the ISO brake failure 
symbol, the agency noted that it is part of a family 
of brake symbols under development by that or- 
ganization. The basic brake symbol can be describ- 
ed as a circle with parentheses, representing brake 



shoes, on each side. The symbol for brake failure 
includes an exclamation mark inside the circle. 

Mercedes' petition cited the November 1982 
NPRM for suggesting an anticipated safety benefit 
resulting from the fact that symbols convey infor- 
mation more quickly and with less chance of 
human error, particularly for the large foreign 
language speaking population, an anticipated cost 
benefit for manufacturers selling vehicles in and 
outside the United States, and promotion of inter- 
national harmonization. 

While the agency addressed most of the amend- 
ments proposed by the November 1982 NPRM in 
its July 1984 notice, it decided to include the issue 
of the brake failure symbol in its examination of 
issues relating to Standard No. 101. Since the 
agency has now reached a conclusion with respect 
to that issue, it will address the issue in this notice. 
As discussed below, the agency has decided not to 
adopt the brake failure symbol in place of the word 
"BRAKE". 

In proposing adoption of the ISO brake failure 
symbol, the agency stated that symbols are 
adopted by the ISO only after extensive interna- 
tional testing as to recognizability and suitability. 
The November 1982 NPRM specifically requested 
comments on the recognizability of the brake 
failure symbol. The NPRM also requested com- 
ments on whether there should be a requirement 
for owner's manuals to explain the brake failure 
symbol. 

While manufacturer comments supported adop- 
tion of the ISO brake failure symbol, the comments 
called into question the agency's statement about 
ISO testing as to recognizability. General Motors 
stated: 

One school of thought in the design of symbols 
holds that they should be immediately 
recognizable without training. This position 
led to the studies to which NHTSA alludes 
when saying that ISO symbols are only 
adopted "after extensive international testing 
as to their recog nizability and suitability." 
However, our observation of recent ISO symbol 
development has revealed a tendency to agree 
upon symbols by consensus, without any 
testing to assure recognizability. Whether 
caused by a lack of funding for testing or by a 
shift in philosophy, the result is a greater 
probability that the symbols must be learned. 

A study published by the Society of Automotive 
Engineers, Investigation into the Identification 



PART571;S101-PRE28 



and Interpretation of Automotive Indicators and 
Controls, found the percentage recognition of 
statement and function of the ISO brake symbol to 
be only 26 percent and 21 percent, respectively, 
while the percentage recognition of statement and 
function of the word "Brake" are 87 percent and 52 
percent, respectively. Given the extremely low 
percentage recognition for the ISO brake symbol 
compared to the word "Brake" and the importance 
for safety of drivers understanding the meaning of 
the brake indicator lamp, the agency does not con- 
sider it appropriate to adopt this particular ISO 
symbol, even if an explanation is provided in 
owner's manuals. Many drivers might not read 
their owner's manual, and drivers other than 
original owners would be still less likely to read or 
even have access to the owner's manual. 

Mercedes also requested that the agency adopt a 
related symbol for an antilock system. That sym- 
bol is the same as the ISO brake failure symbol ex- 
cept that the exclamation mark is replaced by the 
letters ABS. Mercedes stated that the use of 
"ABS" as an abbreviation for "Antilock Braking 
System" is widespread and well known to the 
public and that, therefore, recognition problems 
are not to be expected. Mercedes did not provide 
any support for its contention that ABS is well 
known to the public as an abbreviation for antilock 
braking system. In any event, the agency did not 
propose this symbol and therefore, based on lack of 
notice, cannot consider the symbol for purpose of a 
final rule. 

Petitions for Rulemaking 
As indicated above, two petitions for reconsidera- 
tion submitted to the agency after the closing date 
are being treated as petitions for rulemaking, in 
accordance with agency regulations. 

A petition submitted by Fiat was largely along 
the lines of the request by Mercedes to exclude 
horn controls located on the steering wheel hub 
from the identification requirement. In addition to 
some of the same arguments made by Mercedes, 
Fiat emphasized the agency's decision to exclude 
horns on heavy duty trucks from the requirement. 
The agency does not agree that its decision with 
respect to heavy duty trucks necessitates the same 
decision for other vehicles. The location of horn 
controls on heavy duty trucks appears to be more 
standardized than for other vehicles. Also, the 
agency may adopt different requirements for dif- 
ferent types of vehicles based on many considera- 
tions, such as different driver populations, dif- 
ference in magnitude of a safety problem, etc. 



The other petition was submitted by a private in- 
dividual, Mr. C.R. Blydenburgh. That petitioner 
argued that the July 1984 final rule should be 
delayed pending rulemaking for standardized loca- 
tion of controls and displays, a subject which he 
cited as being included in NHTSA's five year plan 
published in 1979. The petitioner argued that such 
standardization of controls and displays is 
necessary to avoid driver confusion when driving 
different vehicles. The petitioner asserted that the 
extended use of international symbols is counter- 
productive in terms of safety as it fails to utilize 
two important human characteristics, habit and 
instinct. The petitioner did not, however, address 
any of the specific amendments made by the July 
1984 final rule or the notice's discussion of those 
amendments, or offer any support for an allegation 
that the rule could adversely affect safety. 

The agency rejects the petitioner's allegation 
that the rule could adversely affect safety, for the 
reasons discussed in the July 1984 notice. While 
the subject of standardized location of controls and 
displays was included in NHTSA's five year plan 
published in 1979, potential action on that subject 
is not relevant to the issuance of the July 1984 
final rule. Thus, Mr. Blydenburgh's petition will 
be addressed separately at a subsequent date. 

For the reasons discussed above, the petition 
submitted by Toyota is granted, the petition sub- 
mitted by BMW is granted in part and denied in 
part, and the other petitions, except for Mr. 
Blydenburgh's for which action will be determined 
at a later date, are denied. 

The amendments are effective immediately. The 
agency notes, however, that the requirement that 
horn controls be identified by the ISO horn symbol 
does not become mandatory until September 1, 
1987. The agency finds good cause for an im- 
mediate effective date since the amendments 
relieve restrictions, while reducing compliance 
costs and having no adverse impacts on safety. 

PART 571-lAMENDED] 

In consideration of the foregoing, 49 CFR Part 
571 is amended as follows: 

§ 571.101 [Amended] 
1. S5.2.1.1 is revised to read as follows: 
S5.2.1.1 The identification of the following need 
not appear to the driver perceptually upright: 

(a) A master lighting switch or headlamp and 
tail lamp control that adjusts control and display 
illumination by means of rotation, or any other 
rotating control that does not have an off position. 



PART571;S101-PRE29 



(b) A horn control. 

2. Table 2 (a) is amended by revising the designa- 
tion for identifying words or abbreviation for the 
Seat Belt Telltale, contained in column 3, to read: 

Fasten Belts or Fasten Seat Belts. Also see 
FMVSS 208. 

3. Table 2 is amended by revising the designa- 
tion for identifying words or abbreviation for the 
Seat Belt Telltale, contained in column 3, to read: 

Fasten Belts or Fasten Seat Belts. Also see 
FMVSS 208. 

§ 571.208 [Amended] 

1. The first sentence of S4.5.3.3(b) is revised to 
read as follows: 

In place of a warning system that conforms to 
S7.3 of this standard, be equipped with the follow- 
ing warning system: At the left front outboard 
designated seating positions (driver's position), be 
equipped with a warning system that activates a 
continuous or intermittent audible signal for a 
period of not less than 4 seconds and not more than 
8 seconds (beginning when the vehicle ignition 
switch is moved to the "on" or the "start" position) 
when condition (A) exists simultaneously with 
either condition (B) or condition (C), and that ac- 
tivates a continuous or flashing warning light, 
visible to the driver, displaying the identifying 



symbol for the seat belt telltale shown in Table 2 of 
FMVSS 101 or, at the option of the manufacturer if 
permitted by FMVSS 101, displaying the words 
"Fasten Seat Belts" or "Fasten Belts". 

2. The first sentence of S7.3 is revised to read as 
follows: 

A seat belt assembly provided at the driver's 
seating position shall be equipped with a warning 
system that activates, for a period of not less than 
4 seconds and not more than 8 seconds (beginning 
when the vehicle ignition switch is moved to the 
"on" or the "start" position), a continuous or 
flashing warning light, visible to the driver, 
displaying the identifying symbol for the seat belt 
telltale shown in Table 2 of FMVSS 101 or, at the 
option of the manufacturer if permitted by FMVSS 
101, displaying the words "Fasten Seat Belts" or 
"Fasten Belts", when condition (a) exists and a 
continous or intermittent audible signal when con- 
dition (a) exists simulanteously with condition fb). 

Issued on May 29, 1985 



Diane K. Steed 
Administrator 

50 F.R. 23426 
June 4, 1985 



PART 571; SlOl-PRE 30 



PREAMBLE TO AN AMENDMENT TO MOTOR VEHICLE 
SAFETY STANDARD NO. 101 

Controls and Displays 
[Docket No. 1-18; Notice 28] 



ACTION: Final rule. 

SUMMARY: The purpose of this notice is to amend 
Federal Motor Vehicle Safety Standard No. 101, 
Controls and Displays, to permit greater flexibil- 
ity in the illumination and identification of controls 
and displays. The amendments are adopted in 
response to several petitions for rulemaking. 

The amendments allow gauges to have a two- 
level lighting intensity, rather than being con- 
tinuously variable over a wide range. They 
distinguish between critical telltales, such as the 
turn signal indicators, which must be visible under 
all lighting conditions, and less critical telltales, 
such as the water temperature indicator, which are 
permitted the same range of intensity as gauges. 
The categorization of certain displays as informa- 
tional readout displays and the specification of 
special illumination requirements for those 
displays is discontinued. 

To accommodate new display technologies 
capable of showing information about different 
telltales and gauges on a single display screen; the 
amendments permit the cancellation of messages, 
but require them to be retrievable by the driver. 
They also permit messages to be automatically 
sequenced. 

The amendments allow the use of specified words 
to identify controls and displays, as an alternative 
to the symbols formerly required for many controls, 
and permit the use of symbols "substantially 
similar" to those specified. 

DATES: The requirements of S5.3.3(bKl) and 
S5.3.3(cXl) are effective September 1, 1989. All 
other amendments are effective March 5, 1987. 

SUPPLEMENTARY INFORMATION: In a notice of 
proposed rulemaking (NPRM) published on 
September 12, 1985 (50 FR 37240), NHTSA 
responded to a number of issues related to Stand- 
ard No. 101, Controls and Displays. These issues 
had been raised by petitions for rulemaking and 
by comments on earlier NPRM's. The notice set 



forth a number of proposed amendments to the 
lighting intensity and identification requirements 
of the standard. Upon reviewing the comments on 
the proposal, the agency has concluded that several 
of the proposed amendments should be adopted, but 
that others should not. In the discussion that 
follows, each amendment appears in the same 
order as in the NPRM. 

Lighting Intensity Requirements 

The NPRM dealt with several questions 
presented by the advent of new display 
technologies, among them questions about the 
appropriate lighting intensity for the different 
types of displays, the grouping of displays with 
differing intensity requirements into a single 
cluster, the need to vary lighting intensity accord- 
ing to the outside conditions, and the use of a 
common space, such as a small TV screen, to 
display messages in sequence. 

The standard divides displays into two broad 
categories: telltales and gauges. It defines a telltale 
as 
a display that indicates, by means of a light- 
emitting signal, the actuation of a device, 
existence of a correct or defective condition, or of 
a failure to function. 
Telltales include the turn signal indicators, the 
high-beam indicator, and the brake failure warn- 
ing. The standard defines a "gauge" as any display 
listed in the standard (S5.1 or Table 2) that is not 
a telltale. Gauges include such displays as the 
speedometer and the odometer. 

As discussed at greater length in the preamble 
to the NPRM, the current intensity requirements 
for telltales differ from those for gauges. The 
lighting for a telltale must be of a single fixed 
intensity that makes the telltale visible under all 
daytime and nighttime conditions, while the light- 
ing for a gauge must be continuously variable over 
a range of intensities. 

In an attempt to accommodate new display 
technologies capable of showing more than one 



PART 571; SlOl-PRE 31 



message or symbol on a single screen, the agency 
amended the standard in 1978 to place those 
displays into a separate category called informa- 
tional readout displays (IRD). Although IRD's were 
required to have two intensity levels— one for 
daytime and a lower level for nighttime— the fixed 
intensity of the telltales prevented the manufac- 
turers from including telltales in IRD's. 

In response to a petition by General Motors seek- 
ing to accommodate telltales in IRD's and a 
petition by BMW to include telltales among the 
messages displayed in sequence in a common 
message center, NHTSA examined the safety 
implications of changing the lighting intensity 
requirements for gauges and telltales. In the 
NPRM, the agency proposed several amendments 
to these requirements. 

A. Lighting intensity Requirements for Gauges 

The NPRM proposed to amend the provisions 
relating to gauges and IRD's to reduce the number 
of different sets of lighting requirements and to en- 
sure that drivers are provided with the means for 
making gauges visible under all lighting condi- 
tions. It proposed to amend S5.3.3 to apply the bi- 
level lighting requirements of IRD's to all gauges, 
so that the lighting for a gauge and its identifica- 
tion would no longer have to be continuously 
variable. One lighting level would have to be 
"barely discernible to a driver who has adapted to 
dark ambient roadway conditions," continuing 
that criterion from the current S5.3.3. The in- 
tensity could be adjusted either manually or 
automatically, and could have a level at which the 
gauge would not be visible under some lighting 
conditions. If the brightness level could be 
automatically adjusted, there would have to be a 
means to allow the driver to override manually the 
adjustment to restore visibility. In consequence of 
proposing to make the lighting requirements for 
gauges and IRD's identical, the NPRM proposed 
to delete the term Informational Readout Display 
and the separate IRD light intensity requirement 
from the standard as no longer useful. 

The comments on the proposed amendment to 
S5.3.3 focussed on the requirement that a gauge 
must have at least two levels of brightness 
(S5.3.3(bXl)), and on the requirement that an 
automatic adjustment have a manual override to 
allow the driver to restore visibility (S5.3.3(c)). 
General Motors stated that each of these require- 
ments could require a change in hardware that had 
been developed to meet the IRD criteria. However, 
there exists general agreement among all 
commenters (including GM) with the proposal to 
require that gauges have more than one level of 



brightness. GM, in its comments, indicates that 
such a requirement will provide for good visibility 
of the gauges and also provide the means to pre- 
vent glare during darker ambient conditions. 

However, GM also commented that when a tell- 
tale is incorporated in a cluster of gauges, and the 
telltale is actuated, the gauges need not be 
required to be variable in intensity. The agency 
believes that gauges should always have the 
capability of being adjusted and will not, for the 
reasons discussed below, permit the exemption that 
GM requested. 

Although telltales are generally intended to alert 
the driver to an unsafe or unwanted condition and 
thus would not normally be illuminated for other 
than short periods of time, this is not always the 
case. Many vehicles now incorporate telltales 
whose nature is more related to providing general 
information than to denoting an emergency situa- 
tion. Telltales such as, for example, one indicating 
the need to service emission equipment may often 
be illuminated for considerable driving periods. In 
such instances the agency concludes that the 
brightness of gauges should be capable of being 
adjusted. 

GM has not presented any compelling evidence 
to contradict this conclusion. Having a major por- 
tion of a gauge cluster illuminated at full 
brightness for a lengthy time period without 
manual control would be inconsistent with the 
general consensus of the commenters, as noted 
above. 

The agency believes that the requirements of the 
existing standard may be ambiguous in this 
regard. Because of the possible ambiguity and the 
need to modify any existing designs which would 
not comply with the new requirement, the effec- 
tive date for this section of the proposed amend- 
ment (S5.3.3) is September 1, 1989. 

A second question presented by GM concerning 
S5.3.3(bKl) involves continuously variable lighting. 
As proposed in the NPRM, S5.3.3(bXl) would 
require at least two levels of brightness, one of 
which would have to be "barely discernible to a 
driver who has adapted to dark ambient roadway 
conditions." GM asked whether a means of con- 
tinuously varying the level of brightness, such as 
a rheostat, could have a position at which no light 
is emitted, as permitted by the current S5.3.3. The 
agency intends no change in the regulation of con- 
tinuously variable lighting. By requiring "at least" 
two levels of brightness, S5.3.3(bXl) implicitly per- 
mits the control to have additional levels of 
brightness, with no restrictions as to whether such 
levels are above or below the '"barely discernible" 
level. 



PART 571; SlOl-PRE 32 



The remaining question raised by the comments 
on S5.3.3 concerns the requirement in S5.3.3(c) that 
if the brightness is automatically adjusted to a 
level where it is not visible to the driver, a means 
must be provided to enable the driver to restore 
visibility. This provision is intended to regulate 
systems such as those that reduce the brightness 
of the controls and displays when the headlamps 
are turned on, regardless of the ambient light 
conditions. If automatic brightness controls can be 
developed that employ photosensitive devices to 
provide adequate visibility under any ambient 
light conditions, these controls would not be sub- 
ject to the provision. In proposing this requirement, 
the agency expressed the view that driving with 
headlamps on during the daytime was a suffi- 
ciently frequent occurrence to necessitate a control 
to allow the driver to override the effect of the 
headlamp control. 

Notwithstanding objections from General Motors 
to the effect that there are no field data to indicate 
a safety problem from the diminished daytime 
visibility of IRD's, the agency regards the non- 
visibility of crucial information from displays as 
a self-evident safety problem. The remedy, a 
manual override control to increase the displays' 
brightness, is inexpensive and technically simple. 
The agency is accordingly adopting S5.3.3(c) as 
proposed, but with an effective date of September 
1, 1989, to permit manufacturers whose displays 
lack an override to incorporate this feature in an 
efficient manner. 

As proposed in the NPRM, the new S5.3.3 
regulates the visibility of controls as well as that 
of gauges. The comments to the NPRM did not 
object to this proposal. Finally, the new S5.3.3 
eliminates the use of the term "informational 
readout display." As proposed in the NPRM, the 
final rule also deletes the definition of that term 
from S4. 

B. Lighting Intensity Requirements for Telltales 

As part of the proposal to allow gauges and 
telltales to be more readily combined in common 
displays, the NPRM proposed to permit (but not 
require) most telltales to have the same range of 
lighting intensity as gauges. Means would have to 
be provided to make them visible under all condi- 
tions, but they could also be adjustable to levels 
at which they would not be visible under some driv- 
ing conditions (S5.3.5). The four telltales that were 
considered to be critical— those for brakes, high 
beams, turn signals, and seat belts— could also be 
adjustable, but only to levels at which they would 
be visible under any driving condition (S5.3.4). The 
critical telltales would thus have to have a source 



of illumination separate from that of any telltale 
or gauge that could be reduced to a level of 
invisibility. 

The comments supported the proposed distinction 
between critical and non-critical telltales, but 
several comments objected to classifying the safety 
belt telltale as a critical telltale. These objections 
arose mainly from the proposed S5.4, which would 
have prohibited the inclusion of the critical 
telltales in a common space, and are discussed in 
greater detail in the portion of this preamble deal- 
ing with that section. Sections S4.5.3.3 and S5.7.3 
of Standard No. 208, Occupant Protection, require 
"a continuous or flashing warning light, visible to 
the driver," if a manual belt is not used or if an 
automatic belt is disabled. It would be inconsistent 
with the provisions of Standard No. 208 for Stand- 
ard No. 101 to permit the safety belt telltale to be 
reduced in brightness to the point of invisibility. 
Hence, the safety belt telltale is retained as one 
of the telltales which may not be adjusted under 
any conditions to the point of invisibility. 

In response to a comment by GM pointing to a 
potential ambiguity in the drafting of S5. 3. 4(b) and 
S5.3.5(b), the final rule makes it clear that the 
minimum brightness level permitted for a critical 
telltale varies according to the ambient light con- 
ditions. The key requirement is that at any specific 
level of ambient light, a critical telltale may not 
be adjustable to a level that is invisible. 

To simplify the standard somewhat, the final rule 
consolidates the proposed S5.3.4 and S5.3.5 into 
one section, S5.3.4, and makes additional editorial 
changes. 

C. Other Lighting Intensity Requirements 

In the NPRM, the agency proposed a new section 
S5.3.6 to require a means of varying the light 
intensity for any passenger compartment illumina- 
tion within the driver's forward field of view, 
including illumination "for pm-poses other than the 
controls and displays subject to" Standard No. 101. 
This illumination would have been required to 
provide at least two levels of brightness. Although 
the former S5.3.3 required a variable intensity for 
any illumination that is provided "when and only 
when the headlights are activated," the proposal 
would have included other illumination, such as 
the LED display for a clock, that is controlled by 
the ignition. The NPRM noted that clocks and 
other sources of illumination can present the same 
problems of glare as any of the gauges, and that 
these sources should be subject to a similar 
regulation. 

This proposal drew a number of comments, most 
of them adverse. A common view in the comments 



PART 571; SlOl-PRE 33 



was that the proposed requirement should not 
apply to light sources such as glove boxes, vanity 
mirrors.and under-dash courtesy lights that are 
rarely, if ever, illuminated while the vehicle is in 
motion (British Leyland, Chrysler). Many of these 
light sources were said to be peripheral and of low 
intensity, so as not to require variable adjustment 
(GM). Their modificaiton was predicted to entail 
cost and leadtime problems (GM, Ford). One com- 
menter sought to exclude vehicles which are nor- 
mally operated with the passenger compartment 
illuminated (Flxible). The general view was that 
the existing regulation was adequate. 

After considering these comments, NHTSA has 
decided to adopt a provision closer to that of S5.3.3 
as it existed before the issuance of these amend- 
ments. The amended provision, now designated as 
S5.3.5, applies only to those sources of illumina- 
tion which are capable of being illuminated while 
the vehicle is in motion, thereby excluding lamps 
such as courtesy lamps which are actuated by open- 
ing the door. It provides that a source of illumina- 
tion may have either a variable intensity, a single 
intensity that is barely discernible to a driver 
whose eyes have adjusted to dark ambient condi- 
tions, or a means of being turned off. The manufac- 
turers may thus choose any of three options for 
eliminating glare from these sources of illumina- 
tion. The agency believes that this combination of 
options meets each of the objections voiced by the 
comments, while maintaining essential limits on 
glare. In response to the comment by Flxible, the 
section does not apply to buses which are normally 
operated with the passenger compartment 
illuminated. 

D. Multi-Message Displays 

Several manufacturers have developed electronic 
message centers in which more than one telltale 
may be displayed in a single or common space. The 
telltales are typically displayed one at a time. 
Because displaying one telltale cancels any 
preceding telltale, a means must be provided to 
ensure that the driver is aware of each actuated 
telltale. In the NPRM, NHTSA proposed several 
constraints for these multi-message displays: The 
critical telltales— brake, high beam, turn signal, 
and safety belt— were not to be included; a telltale 
was to be displayed at the onset of its underlying 
condition; if the conditions for more than one tell- 
tale existed, an indication was to be given to the 
driver; messages were to be retrievable by the 
driver; messages could be cancelled automatically, 
subject to the driver's retrieval, but could not be 
repeated automatically in sequence; and a visible 



indication of stored messages was to he given the 
driver. 

The proposed S5.4 drew more comments than any 
other portion of the NPRM, some objecting to the 
exclusion of the safety belt telltale from a common 
display (Jaguar, BMW, GM), and most objecting to 
the prohibition of automatic sequencing (SAAB, 
Jaguar, Volkswagen, American Motors, Chrysler, 
BMW, GM, and Ford). Upon further review, the 
agency concludes that these objections have merit 
and therefore adopts S5.4 with changes that 
address the objections. 

The safety belt telltale is regulated by Standard 
No. 208, which specifies separate requirements for 
manual safety belts and for automatic safety belts. 
The telltale for a manual belt at the driver's 
seating position must be actuated for 4-8 seconds 
after the ignition is turned "on" if the driver's belt 
is not fastened. This telltale could be incorporated 
into a multi-message display, as long as it preempts 
other messages and is visible during the time that 
Standard No. 208 requires it to be actuated. The 
telltale for an automatic belt system at the driver's 
position must meet more stringent requirements. 
If the belt is unbuckled, if the webbing release 
mechanism has been actuated, or if the automatic 
belt positioning motor h^s not locked the belt into 
place at the anchorage point, the telltale is 
required to be continuous or flashing as long as the 
condition exists. 

In view' of these distinctions, the agency is 
limiting the reference to the safety belt telltale in 
S5.4(a) to a telltale associated with an automatic 
safety belt. Under Standard No. 208, such a telltale 
could not be cancellable as long as the safety belt 
is disabled by one of the three conditions described 
above. The agency has not proposed to amend 
Standard No. 208 to permit cancellation, and does 
not regard a de facto amendment through Standard 
No. 101 to be appropriate. 

Upon reexamination of the issue of automatic 
sequencing, the agency has concluded that 
automatic sequencing for messages other than the 
critical telltales has advantages which outweigh 
the potential drawbacks discussed in the NPRM. 
The principal advantage is that automatic sequenc- 
ing eliminates the need for a driver to remember 
how to retrieve a message in the rare event that 
two or more telltales are actuated at the same time. 
Although the NPRM mentioned the possibility that 
a driver might be distracted by a flashmg sequence 
of messages, there is also a possibility that the 
driver could be distracted by his attempt to 
manually retrieve a stored message. On balance, 
NHTSA has concluded that automatic sequencing 
should not be prohibited, and is therefore deleting 



PART 571; SlOl-PRE 34 



the prohibition from S5.4.4. In doing so, however, 
the agency cautions that any multi-message 
display conveying safety information should not be 
so burdened with non-safety messages as to 
diminish the value of the display as a safety 
reminder to the driver. 

E. Other Display Requirements 

As part of its proposal to eliminate the term 
"informational readout display," NHTSA proposed 
to apply the color requirements of S5.3.2 to the 
displays which would have been classified as IRD's. 
The agency noted that the use of the specified 
colors appeared to help drivers understand the 
meaning and importance of messages, but it 
invited comments on the difficulty of applying 
these requirements to electronic displays. 

The comments on the color requirements ranged 
from full support (Robert Schlegel), to a request 
that they be discontinued for non-critical telltales 
(GM), to opposition to any color requirements for 
telltales (American Motors, Ford). Ford and GM 
each stated that the single-color displays permitted 
for IRD's had had no adverse effects on safety. GM 
noted that prohibiting such displays would inhibit 
certain new applications such as monochromatic 
cathode ray tubes (CRT's). Ford offered the 
example of its message center, which is 
monochromatic but offers the advantge of display- 
ing a large amount of information in a small space. 

On reviewing the value of color requirements vis- 
a-vis the other available means of enabling the 
driver to distinguish among various telltales, the 
agency has concluded that the color requirements 
should continue to apply to critical telltales, but 
that they need not apply to other telltales. The 
physical separation of the critical telltales fi"om the 
other telltales, and the differing lighting intensi- 
ty applicable to the critical telltales, have the effect 
of requiring them to have a separate source of 
illumination. The retention of the color require- 
ments for these telltales should therefore be 
compatible with existing designs and should not 
require any redesign. 

In a related act-on, the agency also proposed to 
amend the definition of "telltale" to delete the 
phrase "by means of a light-emitting signal." This 
proposal would permit the use of new displays, such 
as liquid crystals, that might have been prohibited 
by the deleted phrase. It received no adverse com- 
ments and the definition is therefore amended for 
the reasons given in the NPRM. 

Identification Requirements 

In response to issues raised in three petitions for 
rulemaking (GM, VW and BL Technology), the 



NPRM addressed a variety of issues concerning the 
identification requirements for controls and 
displays. Although the agency declined to adopt a 
suggestion by GM that the requirements be 
removed from the safety standard and placed in a 
regulation, it proposed amendments to make the 
requirements more flexible. The first of these was 
an amendment to permit the use of specified words 
as an alternate means of identifying controls and 
displays for which symbols had previously been the 
exclusive identification. If a manufacturer used the 
word or symbol specified for a control or display, 
the NPRM proposed to allow the manufacturer to 
use additional identification. Finally, the NPRM 
proposed to permit the use of symbols which 
substantially resemble those specified in the tables. 
There were no objections in the comments to 
these proposals. Two comments, however, con- 
tained requests for the use of specific words and 
symbols. General Motors requested the use of 
"Wiper-Washer" as an alternative to "Wipe- 
Wash," to identify the windshield wiping and 
washing control, and "R-Def ' as an alternative to 
the phrases proposed to identify the rear defroster 
control. The agency believes that each of these 
alternatives would be readily comprehended by the 
average driver and is accordingly including them 
in Table I. 

Mercedes-Benz requested that three symbols— 
the ISO symbols for the manual choke, the heater, 
and the air conditoner— be listed in Table I as alter- 
natives to the words now specified for those 
controls. The agency has previously considered 
petitions regarding each of these symbols, and has 
declined to permit their use as alternatives to the 
specified words. The agency remains convinced 
that none of the three symbols is intuitively 
recognizable by the average driver in this country. 
As stated in the NPRM, the effectiveness of 
symbols as identifiers has been called into question 
in recent studies. The agency finds no reason to 
alter its earlier decision and accordingly declines 
to permit the use of the symbols requested by 
Mercedes. 

Effective Date 

In view of the extensive redesign of displays 
required by S5.3.3(bXl) and S5.3.3(cXl), the agency 
has determined that an effective date of September 
1, 1989, for these sections is in the public interest. 
The other amendments relieve restrictions and the 
agency has therefore determined that an effective 
date of 30 days after publication in the Federal 
Register is in the public interest. 

In consideration of the foregoing, 49 CFR Part 
571 is amended as follows: 



PART 571; SlOl-PRE 35 



1. Section S.4 is amended by removing the 
sentence defining "information readout display." 

2. Section S.4 is amended by removing the 
phrase "by means of a light emitting signal" from 
the definition of "Telltale." 

3. The first two sentences of section S.5.2.1(a) are 
revised to read as follows: 

(a) Except as specified in S5.2.1(b), any hand- 
operated control listed in column 1 of Table 1 that 
has a symbol designated for it in column 3 of that 
table shall be identified by either the symbol 
designated in column 3 (or symbol substantially 
similar in form to that shown in column 3) or the 
word or abbreviation shown in column 2 of that 
table. Any such control for which no symbol is 
shown in Table 1 shall be identified by the word 
or abbreviation shown in column 2. * * * 

4. Section S5.2.3 is revised to read: 

Any display located within the passenger com- 
partment and listed in column 1 of Table 2 that has 
a symbol designated in column 4 of that table shall 
be identified by either the symbol designated in 
column 4 (or symbol substantially similar in form 
to that shown in column 4) or the word or abbrevia- 
tion shown in column 3. Additional words or 
symbols may be used at the manufacturer's dis- 
cretion for the purpose of clarity. Any telltales used 
ir( conjunction with a gauge need not be identified. 
The identification required or permitted by this 
section shall be placed on or adjacent to the display 
that it identifies. The identification of any display 
shall, under the conditions of S6, be visible to the 
driver and appear to the driver perceptually 
upright. 

5. Table 1(a) is amended by adding the words "or 
washer-wiper" after "wash-wipe" as identifying 
words for combined windshield washing and wip- 
ing systems in column 2, and by amending the 
identifying words for rear window defrosting and 
defogging systems in column 2 to read: "Rear 
Defrost, Rear Defog, Rear Def, or R-Def." 

6. Section S5.3.2 is revised to read as follows: 
S5.3.2. Each telltale shall be of the color shown 

in column 2 of Table 2. The identification of each 
telltale shall be in a color that contrasts with the 
background. 

7. Table 2 is amended by deleting the colors 
designated under Column 2 for all telltales other 
than those for "Turn Signal," "High Beam," and 
"Malfunction in Anti-Lock or Brake System." 

8. Section S5.3.3 is revised to read: 

5.3.3(a) Means shall be provided for making con- 
trols, gauges, and the identification of those items 
visible to the driver under all driving conditions. 

(b) The means for providing the required 
visibility— 



(1) Shall be adjustable, except as provided in 
S5.3.3(d), to provide at least two levels of 
brightness, one of which is barely discernible to a 
driver who has adapted to dark ambient roadway 
conditions. 

(2) May be operable manually or automatically, 
and 

(3) May have levels of brightness at which those 
items and their identification are not visible. 

(c) Effective September 1, 1989, if the level of 
brightness is adjusted by automatic means to a 
point where those items or their identification are 
not visible to the driver, a means shall be provided 
to enable the driver to restore visibility. 

(d) For a vehicle manufactured before September 
1, 1989, the requirements of S5.3.3(bXl) shall not 
apply to any gauge during the actuation of a 
telltale which shares a common light source with 
the gauge. 

9. A new section S5.3.4 is added to read: 
5.3.4(a) Means shall be provided that are capable 

of making telltales and their identification visible 
to the driver under all driving conditions. 

(b) The means for providing the required visi- 
bility may be adjustable manually or automati- 
cally, except that the telltales and identification 
for brakes, high beams, turn signals, and safety 
belts may not be adjustable under any driving 
condition to a level that is invisible. 

10. A new section S5.3.5 is added to read: 
S5.3.5 Any source of illumination within the 

driver's forward field of view which is not used for 
the controls and displays regulated by this stand- 
ard, and which is capable of being illuminated 
while the vehicle is in motion, most have either a 
variable intensity, a single intensity that is barely 
discernible to a driver who has adapted to dark 
ambient roadway conditions, or a means of being 
turned off. This requirement shall not apply to 
buses that are normally operated with the 
passenger compartment illuminated. 

11. A new section S5.4 is added to read: 

S5.4 A common space may be used to display 
messages from any sources, subject to the follow- 
ing requirements: 

(a) The telltales for the brake, high beam, and 
turn signal, and the safety belt telltale required 
by S4.5.3.3 of Standard No. 208 may not be shown 
on the common space. 

(h) Except as provided in S5.4(e), the telltales 
listed in Table 2 shall be displayed at the initiation 
of any underlying condition. 

(c) When the underlying condition exists for 
actuation of two or more messages, the messages 
shall be either— 

(1) repeated automatically in sequence, or 



PART 571; SlOl-PRE 36 



(2) indicated by visible means and capable of 
being selected by the driver for viewing. 

(d) Messages may be cancellable automatically 
or by the driver. 

(e) The safety belt telltale must be displayed and 
visible during the time specified in S7.3 of Stand- 
ard No. 208. 

12. Table 2 is amended by placing "7" as an 
additional superscript for the color of the safety belt 
telltale and by adding the following as footnote 7: 

The color of the telltale required by S4.5.3.3 of 
Standard No. 208 is red; the color of the telltale 



required by S7.3 of Standard No. 208 is not 
specified. 

Issued on Jan. 29, 1987 



Diane K. Steed 
Administrator 

52 F.R. 3244 
February 3, 1987 



PART 571; SlOl PRE 37 38 



PREAMBLE TO AN AMENDMENT TO MOTOR VEHICLE SAFETY STANDARD NO. 101 

Hydraulic Brake Systems; Controls and Displays 
[Dockets No. 1-18, Notice, 32; No. 70-27, Notice 31] 



ACTION: Final rule. 

SUMMARY: Federal Motor Vehicle Safety Stand- 
ards No. 105, Hydraulic Brake Systems, and No. 
101, Controls and Displays, have required telltales 
whose single function is indicating failure in the 
antilock portion of a brake system to read 
"ANTILOCK." This notice amends those stand- 
ards to permit "ABS," an abbreviation for "Anti- 
lock Brake System," as an alternative. 

DATES: The amendments made by this rule are 
effective June 29, 1987. 

SUPPLEMENTARY INFORMATION: Federal Motor 
Vehicle Safety Standard No. 105, Hydraulic Brake 
Systems, requires an indicator lamp, i.e., a telltale 
on the dashboard, to be activated whenever there 
is a total functional electrical failure in an antilock 
brake system. The manufacturer may meet this re- 
quirement by using a common indicator display- 
ing the word "BRAKE," which also warns the 
driver about other types of brake failure. Alter- 
natively, the manufacturer may provide a separate 
indicator for antilock failure. 

If the manufacturer uses a separate indicator for 
antilock failure, Standard No. 105 and Standard 
No. 101, Controls and Displays, have specified that 
the indicator must read either "ANTILOCK" or 
"ANTI-LOCK." On April 16, 1986, NHTSA 
published a notice of proposed rulemaking (NPRM) 
in the Federal Register (51 FR 12900) to permit 
"ABS," an abbreviation for "Antilock Brake 
System," as an alternative. 

As discussed in the NPRM, this rulemaking ac- 
tion resulted from a petition for rulemaking sub- 
mitted by Mercedes-Benz. That company stated 
that the letters "ABS" have been used in 
automotive press articles and in manufacturers' 
print advertising, with few exceptions, for identi- 
fying brake systems with antilock capabilities. 
Copies of such publications were submitted with 
the petition. The petitioner contended that as anti- 
lock brake systems increase in availability, the ab- 
breviation will be increasingly used by the media, 
in technical publications, and in owners' manuals, 



and is expected to remain synonymous with this 
type of brake system. 

Mercedes also argued that if a manufacturer of- 
fers a system or feature not required by regulation, 
but provides a corresponding telltale required by 
regulation, that telltale message should be per- 
mitted to correspond with the campaigns developed 
to promote such safety systems. That company 
compared the use of "ABS" in its marketing of 
antilock braking systems to the use of "SRS" in 
marketing its Supplementary Restraint System. 

In the NPRM, NHTSA stated that it believed 
that the primary issue it must consider in respond- 
ing to Mercedes' petition is the recognizability and 
understanding of "ABS" as compared to 
"ANTILOCK," both by new car buyers and other 
drivers. For example, in deciding not to adopt the 
International Standards Organization (ISO) brake 
symbol as an alternative to the word "BRAKE" in 
common indicators, the agency noted a Society of 
Automotive Engineers (SAE) study indicating ex- 
tremely low percentage recognition for the ISO 
brake symbol compared to the word "BRAKE," 
and the importance for safety of drivers under- 
standing the meaning of the brake indicator lamp. 
See 50 FR 23430 (June 4, 1985). 

NHTSA indicated in the NPRM that it was 
unaware of data concerning the recognizability and 
understanding of "ANTILOCK" or "ABS." The 
agency recognized that, unlike some identifying 
words and abbreviations, the abbreviation ABS ap- 
pears to require learning by the driver in order to 
understand its meaning. However, given the use 
of ABS by the media and in marketing campaigns, 
the agency agreed with the petitioner that such 
learning is likely to be taking place and to continue 
to do so. The agency also noted that the word 
"ANTILOCK" requires learning by the driver in 
order to understand its meaning, since antilock 
technology is relatively new and unfamiliar to 
most drivers. NHTSA specifically requested com- 
ments and data on the recognizability and 
understanding of "ANTILOCK" and "ABS." 

NHTSA received nine comments on the NPRM, 



PART 571; SlOl-PRE 39 



some of which favored the proposal and some of 
which opposed it. Commenters supporting the pro- 
posal include Chrysler, Ford, Volkswagen, BMW, 
American Motors (AMC) and Volvo. Chrysler 
stated that with the expected increase in usage of 
antilock brake systems and accompanying owner 
information and advertising campaigns, both 
"ANTILOCK" and "ABS" should be recognizable 
and understandable to drivers of those cars. Ford 
stated that it supports the proposal since (1) it 
represents more efficient use of space in labelmg 
a small telltale, (2) that company has used the term 
"ABS" to designate its antilock brake systems, (3) 
the "ABS" designation has been recognized by the 
International Standards Organization (ISO) as part 
of one of its proposals for an antilock brake sym- 
bol, and (4) that company probably would employ 
the "ABS" identification in its products worldwide 
if it is permitted by NHTSA for use in the United 
States. That company cited data suggesting that 
"ABS" currently has lower recognition than 
"ANTILOCK," but pointed out that an abstract 
symbol, such as "ABS," can be learned just like 
a word in another language or a new slang word. 
BMW asserted that since both antilock braking 
systems and separate telltales for them are volun- 
tarily provided, manufacturers should be provided 
maximum flexibility in telltale identification. That 
company stated that both messages are equally 
unknown to the driving public and that neither is 
self-explanatory. BMW also noted that, unlike the 
other required brake telltales, complete loss of this 
function does not interfere with normal braking. 
That commenter stated that this is refiected by 
Standard No. lOl's traditional designation of the 
color yellow for this telltale, in contrast to red for 
the others, indicating less urgency. AMC 
acknowledged that the introduction of "ABS" 
would necessitate some education of drivers, but 
asserted that it is opportune that this be done now, 
as the new antilock technology' is gi-adually being 
integrated into vehicle designs. Volkswagen noted 
that while the provision of multiple brake indicator 
lights can add significantly to the amount of infor- 
mation provided to the driver, the amount of in- 
formation which can be printed on a telltale is 
usually quite limited. That company supported use 
of "ABS," arguing that inflexibility with regard 
to the abbreviated message to be displayed is not 
reasonable. 

Commenters opposing the proposal include 
Honda, Renault, and a private individual, Mr. 
Robert F. Schlegel, Jr. Honda stated that other ab- 
breviations for Antilock Brake System are in use 
by other manufacturers, including "ALB" (Anti- 
Lock Brake), "ASBS" (Anti-skid Brake Svstem), 



"ESC" (Electronic Skid Control), and "SCS" (Stop 
Control System). That commenter stated that these 
various abbreviations, including "ABS," are 
trademarks, and expressed concern that the wide 
use of "ABS" with the Bosch antilock brake system 
may lead consumers to believe that any vehicle 
with a telltale showing the letters "ABS" is equip- 
ped with a Bosch system. Based on this concern, 
Honda argued that it is neither wise nor lawful for 
NHTSA to permit such use. Renault similarly com- 
mented that the abbreviation "ABS" is commonly 
associated with a particular anti-skid device, or 
with a particular manufacturer. That company 
stated that there is no reason to assign a greater 
value to this abbreviation than to other ones which 
may appear. Renault stated that the French 
manufactiu-ers have proposed a pictorial symbol for 
antilock failure to the ISO, which is also currently 
considering two other symbols. Since the ISO has 
not yet ruled on an international symbol for anti- 
lock failure, that commenter reque.sted that Stand- 
ards No. 101 and No. 105 not be amended at this 
time. Renault also argued that if "ABS" is permit- 
led, other symbols, particularly those before the 
ISO, should also be permitted. Mr. Schlegel argued 
that the word "ANTILOCK" conveys more infor- 
mation than "ABS" to the vast majority of drivers, 
contending that symbols must provide a pictorial 
or verbal clue. According to that commenter, there 
are too many acronyms arriving lately that are not 
understood by the general public. 

After careful consideration of the comments, 
NHTSA has decided to permit the use of "ABS" 
as an alternative to "ANTILOCK." The use of 
multiple brake indicators can provide additional 
safety information to the driver, and the agency 
believes that greater flexibility is appropriate. The 
message "ABS" is considerably shorter than 
"ANTILOCK" and is there' ore more easily incor- 
porated into a small telltale. 

NHTSA recognizes that "ABS" will require 
learning on the part of drivers. For example, in an 
informal survey of 40 Ford engineering employees, 
15 percent associated "ABS" with antilock brakes, 
while 72 percent recognized the word 
"ANTILOCK." As indicated, in information pro- 
vided by Mercedes-Benz and BMW. however, the 
term "ABS" is being used in both press aiticles and 
advertising. NHTSA believes that drivers are learn 
ing the meaning of "ABS," and that such learn- 
ing will continue. NHTSA notes that there are dif- 
ferences between this situation and that involved 
in the agency's decision not to permit use of the 
ISO brake symbol. First, the telltale for antilock 
failure is not as ui'gent or critical a waining as that 
for other types of brake failure. Second, there is ex- 



PART571: SlOl-PRE 40 



tensive use of the term "ABS" in press articles and 
advertising, which is not the case for the ISO brake 
symbol. Third, as antilock technology is still in the 
early stages of being introduced to drivers, there 
is a unique opportunity for learning the term 
"ABS." By contrast, drivers have come to expect 
use of the word "BRAKE" for other types of brake 
failure. 

While NHTSA believes that greater flexibility 
is appropriate, it does not believe it would be in the 
interest of safety to permit multiple acronyms or 
symbols. While permitting the use of "ABS" will 
facilitate the learning of that acronym by drivers, 
drivers cannot be expected to learn the meaning 
of multiple acronyms or symbols for the same 
message. NHTSA notes that this action may help 
facilitate international harmonization, since one 
of the symbols being considered by the ISO for 
antilock failure incorporates "ABS." 

Since NHTSA considers it appropriate to permit 
only one alternative to "ANTILOCK," it is 
necessary that use of that alternative be available 
to all manufacturers. Accordingly, the agency con- 
tacted Mercedes-Benz concerning whether its 
parent company, Daimler-Benz, was willing to 
waive protection of its trademark and grant a 
general approval to use "ABS" for all types of 
antilock braking systems. Daimler-Benz executed 
a declaration, which included the following 
statement: 
If the term "ABS" is permitted under 49 CFR 
Part 571, Federal Motor Vehicle Safety Stand- 
ards, by the National Highway Traffic Safety Ad- 
ministration, United States Department of 
Transportation, as an alternative to "ANTI- 
LOCK" for identifying telltales for malfunctions 
in antilock brake systems, Daimler-Benz 
Aktiengesellschaft hereby declares that it waives 
the protection of its trademark and grants a 
general approval to use the term "ABS" as a sym- 
bol for all types of anti-lock brake systems. 
The declaration executed by Daimler-Benz has 
been placed in the docket. NHTSA believes that 
the waiver resolves the trademark concerns raised 



by commenters. Since it is clear that all manufac- 
turers can now use "ABS," the agency does not 
believe consumers will associate the term with any 
particular company. 

Since this amendment imposes no new require- 
ments but instead increases manufacturer flexibil- 
ity by relieving a restriction, NHTSA has deter- 
mined that an effective date of 30 days after 
publication in the Federal Register is in the public 
interest. 
Part 571-lAMENDED] 

In consideration of the foregoing, 49 CFR Part 
571 is amended as follows: 

In Table 2 of 571.101, the identifying words or 
abbreviation for malfunction in anti-lock (row 9, 
column 3, above the dotted line) is revised to read: 

Antilock, Anti-lock, or ABS. Also see FMVSS 
105. 

S5.3.5(a) of 571.105 is revised to read: 

S5.3.5(a) Each indicator lamp shall display word, 
words or abbreviation, in accordance with the re- 
quirements of Standard No. 101 (49 CFR 571.101) 
and/or this section, which shall have letters not less 
than 1/8-inch high and be legible to the driver in 
daylight when lighted. Words in addition to those 
required by Standard No. 101 and/or this section 
and symbols may be provided for purposes of 
clarity. 

S5.3.5(cKlKC) of 571.105 is revised to read: 

(C) If a separate indicator lamp is provided for 
an anti-lock system, the single word "Antilock" or 
Anti-lock," or the abbreviation "ABS," may be 
used for S5.3.1(c). 

Issued on May 21, 1987 



Diane K. Steed 
Administrator 

52 F.R. 19872 
May 28, 1987 



PART 571; SlOl-PRE 41-42 



PREAMBLE TO AN AMENDMENT TO FEDERAL MOTOR VEHICLE 
SAFETY STANDARD NO. 101 

Controls and Displays 
(Docket No. 1-18; Notice 33) 



ACTION: Final rule; response to petitions for 
reconsideration. 

SUMMARY: In a final rule published in the Federal 
Register on February 3, 1987, NHTSA amended a 
number of the requirements of Standard No. 101, 
Controls and Displays. The agency received a 
number of petitions for reconsideration. Some of 
the issues raised by the petitioners were responded 
to in a notice published in the Federal Register on 
March 9, 1987. This notice responds to the rest of 
the issues and makes several changes in the 
standard for purposes of clarification or correc- 
tion. 

EFFECTIVE DATE: The amendments made by this 
rule are effective September 3, 1987. 

SUPPLEMENTARY INFORMATION: In afinal rule 

published in the Federal Register (52 FR 3244) on 
February 3, 1987. NHTSA amended a number of 
the requirements of Standard No. 101, Controls 
and Displays. While the primary purpose of the 
amendments was to permit greater flexibility in 
the illumination and identification of controls and 
displays, the agency recognized that some of the 
amendments could result in the need for manu- 
facturers to modify existing designs. The agency 
adopted an effective date of September 1, 1989, for 
these amendments in order to provide adequate 
leadtime for such modifications. Other amend- 
ments relieved restrictions and were not believed 
to result in the need for design modifications. The 
agency concluded that an effective date of 30 days 
after publication in the Federal Register, i.e., 
March 5, 1987, was in the public interest for these 
amendments. 

NHTSA received petitions for reconsideration 
from the Automobile Importers of America, Inc. 
(AIA), Volkswagen (VW), Volvo. Ford, Chrysler, 
the Motor Vehicle Manufacturers Association 
(MVMA), Nissan, Austin Rover, Mazda and 
Toyota. Many of the petitioners indicated that 
some of the amendments effective on March 5, 1987 
would result in the need for design modifications 
and requested that the effective date for these 
amendments be extended to September 1, 1989. 

After reviewing the petitions, NHTSA concluded 
that some of the amendments would require design 



changes and, accordingly, decided to permit com- 
pliance with either the earlier version of the 
standard or the amended standard until September 
1, 1987. In a final rule published in the Federal 
Register (45 FR 7151) on March 9, 1987, the agency 
reissued the earlier version of Standard No. 101, 
redesignated as Standard No. 100, to apply to 
vehicles manufactured before September 1, 1989. 
The application section of the standard made it 
clear that manufacturers have the option of meeting 
the requirements of Standard No. 101 for any 
control or display as an alternative to Standard No. 
lOO's requirements. Conforming amendments were 
made to the application section of Standard No. 
101. 

NHTSA noted in its March 1987 notice that 
while the petitioners were particularly concerned 
about the March 5, 1987 effective date, they also 
raised other issues, which would be addressed in a 
separate notice. This notice addresses those issues. 
Several petitioners raised issues concerning the 
requirements of section S5.3.5. That section states: 
"Any source of illumination within the driver's 
forward field of view which is not used for the 
controls and displays regulated by this stand- 
ard, and which is capable of being illuminated 
while the vehicle is in motion, must have either 
a variable intensity, a single intensity that is 
barely discernible to a driver who has adapted 
to dark ambient roadway conditions, or a 
means of being turned off. This requirement 
shall not apply to buses that are normally 
operated with the passenger compartment 
illuminated." 
AIA stated that clarification is needed in section 
S5.3.5 to ensure that the term "variable intensity" 
means manually or automatically adjustable in- 
tensity to provide at least two levels of brightness, 
and not continuously variable intensity. Similarly, 
Toyota stated that it assumes that "variable 
intensity" means manually or automatically ad- 
justable intensity to provide at least two levels of 
brightness, neither of which need be barely dis- 
cernible to a driver who has adapted to dark 
ambient roadway conditions, and not continuously 
variable. In order to provide greater clarity, the 
agency is amending section S5.3.5 along the lines 
requested by AIA. With respect to Toyota's under- 
standing that neither of the two levels of brightness 



PART571;S101-PRE43 



need be "barely discernible" to a driver who has 
adapted to dark ambient roadway conditions, the 
agency notes that the purpose of section S5.3.5 is to 
limit glare. Thus, while NHTSA is not setting 
specific requirements for the two levels of bright- 
ness, it expects that manufacturers will consider 
problems of glare as they select levels of brightness. 

AIA and Toyota also requested clarification 
concerning section S5.3.5'suseof theterm "driver's 
forward field of view." AIA asked whether the 
term is intended to apply to controls beneath the 
dash, on the floor console or on the driver's door. 
Toyota requested that NHTSA provide a definition 
of "driver's forward field of view," stating that 
items that should be subject to this section cannot 
be determined because the term is unclear. The 
agency interprets that term to refer to anything 
forward of the driver and within his or her view, 
including peripheral view. In order to clarify the 
meaning of this requirement, NHTSA is replacing 
the phrase which includes "driver's forward field 
of view" with the following phrase: sources of 
illumination within a vehicle's passenger compart- 
ment which are forward of a transverse vertical 
plane 4.35 inches (110.6 mm) rearward of the 
manikin "H" point with the driver's seat in its 
rearmost driving position. The 4.35 inches di- 
mension represents the distance between the Z-Z 
datum line and the rearmost point of the 99th 
percentile eye ellipse (reference SAE JG41 Oct. 
1985). This may include illumination sources 
beneath the dash, on the floor console, and on the 
driver's door. 

Chrysler expressed concern about section S5.3.5's 
requirements as they apply to telltales not otherwise 
regulated by Standard No. 101. That petitioner 
noted that while section S5.3.4 permits the light 
intensity of telltales listed in the standard to be 
either variable or non-variable, so long as they can 
be made visible under all driving conditions, section 
S5.3.5 requires telltales not listed in the standard 
to have a variable intensity, a single intensity 
barely discernible to the driver under nighttime 
conditions, or a means of being turned off. Chrysler 
objected that these requirements preclude use of 
non-variable telltales which are bright enough to 
be seen under all driving conditions. That company 
noted that it and other manufacturers provide a 
number of telltales not listed in Standard No. 101 
that provide important and useful information, 
such as door-liftgate ajar, exterior lamp outage, 
low windshield washer fluid, transmission oil 



temperature, and engine condition. NHTSA agrees 
with the petitioner that manufacturers should be 
permitted to provide these types of telltales with 
non-variable intensity. As suggested by Chrysler, 
the agency is excepting telltales from the require- 
ments of section S5.3.5. 

Austin Rover argued that section S5.3.5 should 
be amended to clarify the requirements for what it 
termed supplemental information displays. Noting 
that the February 1987 final rule deleted the 
definition of "informational readout display" from 
Standard No. 101, that petitioner stated that some 
supplemental information displayed in an informa- 
tional readout display could now be misinterpreted 
to be covered by section S5.3.3's requirements for 
"controls, gauges and the identification of those 
items." Austin Rover stated that "(a)s this element 
is more stringent than the previous requirements 
for informational readout displays, it is in clear 
contradiction to the intent of the amendment as 
stated in the preamble, that being, to provide 
greater flexibility in the illumination and iden- 
tification of controls and displays." The petitioner 
did not describe what it meant by "supplemental 
information" or provide any examples. 

NHTSA notes that the illumination requirements 
of section S5.3.3 apply only to the controls and 
gauges listed in Standard No. 101 (see section S5), 
while section S5.3.5 covers illuminations for con- 
trols and displays not otherwise regulated by the 
standard. Thus, if the "supplemental information" 
referred to by the petitioner is a gauge listed in the 
standard, it is covered by section S5.3.3. On the 
other hand, if the "supplemental information" is a 
gauge not listed by the standard, it is covered by 
section S5.3.5. NHTSA believes that Austin Rover's 
arguments fail to indicate any need for further 
clarification. With respect to the petitioner's 
argument that section S5.3.3's requirements are 
more stringent than the earlier requirements for 
informational readout displays, the agency notes 
that it recognized in both the February 1987 and 
the March 1987 final rule that some of the amend- 
ments would require design changes. 

Ford noted that while the definition of informa- 
tional readout display was removed from the 
standard, the term still appears in the second 
sentence of section S5. 1. The retention of the term 
was inadvertent, and it is therefore being deleted. 
Ford, V W, Toyota and M VM A noted that amend- 
ments to Table 1(a), permitting greater flexibility 
in identifying certain controls, should have been 



PART 571; SlOl-PRE 44 



made to Table 1. While manufacturers currently 
have the option of complying with the requirements 
specified in either Table lor Table 1(a), they must 
comply with the requirements of Table 1, effective 
September 1, 1987. This notice accordingly amends 
Table 1. 

Toyota stated that it assumes that manufacturers 
may comply with either Standard No. 100 or No. 
101 on a control by control (or display or identifica- 
tion) basis and suggested that, in order to minimize 
confusion in this area. Tables 1 and 1(a) should be 
revised in both standards. However, NHTSA 
believes that amendments to Standard No. 100 
could cause confusion. Standard No. 101 is the 
agency's primary standard for controls and 
displays, and the amendments are being made to 
that standard. Standard No. 100 is simply the 
earlier version of the standard, which was reissued 
for purposes ofoptional compliance until September 
1, 1989. Amending both standards would cloud the 
distinction between the two standards. NHTSA 
notes that the application section of Standard No. 
101 states that at the option of the manufacturer, 
motor vehicles manufactured before September 1, 
1989, may comply with the requirements of 
Standard No. 100, mstead of the requirements of 
Standard No. 101, for any control, display, or 
illumination. The agency also notes that there is no 
need to rescind the amendment to Table 1(a) in 
Standard No. 101. 

Ford pointed out a typographical error in the 
February 1987 notice. On p. 3246, in the last 
paragraph of the first column, the notice stated 
that "(t)he amended provision, now designated as 
S5.3.3, applies only to those sources of illumination 
which are capable of being illuminated while the 

vehicle is in motion " This sentence should have 

referred to S5.3.5. 

NHTSA has determined that an immediate 
effective date is in the public interest. The amend- 
ments made by this notice impose no new require- 
ments but instead either increase manufacturer 
flexibility or are for purposes of clarification or 
correction. As discussed above, manufacturers 
must comply with the requirements of Table 1 
rather than Table 1(a), effective September 1, 
1987. Since the amendments permitting greater 
flexibility in identifying certain controls were 
made to Table 1(a) rather than to Table 1, man- 
ufacturers availing themselves of this flexibility 
may as of that date be unable to certify that some of 
their vehicles comply with Standard No. 101, 



absent these amendments. 

In consideration of the foregoing, 49 CFR Part 
571 is amended as follows: 

The introductory text of S5. 1 is revised to read as 
follows: 

S5.1 Location. Under the conditions of S6, each 
of the following controls that is furnished shall be 
operable by the driver and each of the following 
displays that is furnished shall be visible to the 
driver. Under the conditions of S6, telltales are 
considered visible when activated.***** 

S5.3.5 is revised to read as follows: 

S5.3.5 Any source of illumination within the 
passenger compartment which is forward of a 
transverse vertical plane 4.35 inches (110.6 mm) 
rearward of the manikin "H" point with the driver's 
seat in its rearmost driving position, which is not 
used for the controls and displays regulated by this 
standard, which is not a telltale, and which is 
capable of being illuminated while the vehicle is in 
motion, shall have either ( 1) light intensity which is 
manually or automatically adjustable to provide at 
least two levels of brightness, (2) a single intensity 
that is barely discernible to a driver who has 
adapted to dark ambient roadway conditions, or (3) 
a means of being turned off. This requirement does 
not apply to buses that are normally operated with 
the passenger compartment illuminated. 

Table 1 is amended by adding the word "Lights" 
to column 2 as identifying words or abbreviation 
for Master Lighting Switch control, by adding the 
word "Horn" to column 2 as identifying words or 
abbreviation for Horn control, by adding the word 
"Hazard" to column 2 as identifying words or 
abbreviation for Hazard Warning Signal control, 
by adding the words "Wiper or Wipe" to column 2 
as identifying words or abbreviation for Windshield 
Wiping System control, by adding the words 
"Washer or Wash" to column 2 as identifying 
words or abbreviation for Windshield Washing 
System control, by adding the words "Wash-Wipe 
or Washer-Wiper"to column 2 as identifying words 
or abbreviation for Windshield Washing and 
Wiping Combined control, by adding the word 
"Fan" to column 2 as identifying words or ab- 
breviation for Heating and/or Air Conditioning 
Fan control, by adding the words "Defrost, Defog 
or Def" to column 2 as identifying words or 
abbreviation for Windshield Defrosting and De- 
fogging System control, by adding the words "Rear 
Defrost, Rear Defog, Rear Def, or R-Def " to column 



PART 571; SlOl-PRE 45 



2 as identifying words or abbreviation for Rear Issued on August 31, 1987 
Window Defrosting and Defogging System control, 
and by adding the words "Marker Lamps or MK 
Lps" to column 2 as identifying words or abbrevia- 
tion for Identification, Side Marker and/or Diane K. Steed 
Clearance Lamps control. Administrator 

52 F.R. 33416 
Septembers, 1987 



PART 571; SlOl-PRE 46 



PREAMBLE TO AN AMENDMENT TO FEDERAL MOTOR VEHICLE 
SAFETY STANDARD NO. 101 

Controls and Displays 

(Docket No. 90-01; Notice 2) 

RIN: 2127-AD80 



ACTION: Final rule. 

SUMMARY: Federal Motor Vehicle Safety Standard 
No. 101, Controls and Displays, has long required the 
identification of certain controls and displays to be 
perceptually upright to the driver. One of the controls 
subject to this requirement is the cruise control. This 
notice amends the standard to provide that identifica- 
tion of cruise controls need be perceptually upright only 
when the steering wheel is centered. 

EFFECTIVE DATE: The amendments made in this 
rule become effective on November 15, 1991. 

SUPPLEMENTARY INFORMATION: 

Background 

Standard No. 101, Controls and Displays specifies re- 
quirements for the accessibility, identification and 
illumination of controls and displays in passenger cars, 
multipurpose passenger vehicles, trucks and buses. The 
purpose of the standard is to ensure the accessibility 
and visibility of controls and displays to a driver and 
to facilitate their quick and proper identification and 
selection by a driver in order to reduce the safety 
hazards caused by diversion of the driver's attention 
from the driving task, and by mistakes in selecting 
controls. 

Section S5.2 1 of the standard requires certain 
vehicle controls to be identified by specified symbols 
or words and for the identification to be placed on or 
adjacent to the control. That section also requires the 
identification to be visible to the driver and vdth certain 
exceptions, to "appear to the driver perceptually 
upright." The cruise control is one control subject to 
S5.2.1. The cruise control is also knowrn as the auto- 
matic vehicle speed control. 

On January 23 1991 NHTSA published in the Federal 
Register (56 FR 2487) a notice of proposed rulemaking 
(NPRM) to amend Standard No. 101 to provide that 
identification of cruise controls need be perceptually 



upright only when the steering wheel is centered. As 
discussed in that notice, as a result of discussions with 
General Motors (GM), following the issuance of a June 
6, 1990 interpretation letter addressed to Mr. J. A. 
Schurger, the agency determined that there has been 
confusion by a number of manufacturers concerning 
how the perceptually upright requirement applies to 
cruise controls. As a result, some manufacturers have 
placed cruise controls on steering wheels, even though 
the effect of such placement is such that these controls 
are not "perceptually upright" when the steering wheel 
is being turned. After considering arguments raised by 
GM in favor of placing cruise controls on steering 
wheels, NHTSA decided to initiate rulemaking to con- 
sider lessening restrictions on cruise controls and other 
controls or identifications on steering wheels. 

The NPRM focused on the issue of whether there is 
a safety need to prohibit cruise controls from being 
placed on steering wheels. However, the agency noted 
that the issues raised were applicable to any other 
controls or displays that could be mounted on the steer- 
ing wheel or steering column. NHTSA characterized 
the primary issue in the rulemaking not as whether 
steering wheel-mounted cruise controls necessarily 
result in safety benefits, but instead whether there is 
a safety need to prohibit them. The agency tentatively 
concluded that the safety benefits attributable to the 
"perceptually upright" requirement will be achieved 
so long as control identification located on the steer- 
ing wheel is "perceptually upright" when the steering 
wheel is centered. 

NHTSA also proposed, as an alternative, an amend- 
ment that would exclude steering wheel moimted cruise 
controls altogether from the "perceptually upright" 
requirement. 

The agency cited a previous example in which 
NHTSA decided to exclude horn controls entirely from 
the "perceptually upright" requirement. 

The agency then noted that while the identification 
for most cruise controls located on steering wheels is 



PART 571; SlOl-PRE 47 



upright when the steering wheel is centered, the iden- 
tification for at least some cruise controls is at a slight 
angle. The agency stated that the designs at slight 
angles raise two issues. The first issue is whether iden- 
tification which is at a slight angle should be considered 
"perceptually upright" and, if so, at what angle such 
identification would not be considered "perceptually 
upright." The agency did not limit this issue to cruise 
controls on steering wheels but sought comments on 
its relevancy to identification of controls and displays 
which are not located on the steering wheel. 

The second issue relates to the fact that if identifi- 
cation of cruise controls is to be "perceptually upright" 
or close to "perceptually upright" to the driver at those 
times when it is reasonably anticipated that the driver 
will be observing that identification, it is necessary that 
the identification be upright or very close to upright 
when the steering wheel is centered. To the extent that 
cruise control identification is at an angle when the 
steering wheel is centered, that angle could be in- 
creased during gradual turns depending on the direc- 
tion of the angle relative to the direction of the turn. 
NHTSA requested comments on whether identification 
of cruise controls located on steering wheels should be 
required to be upright when the steering wheel is 
centered or whether it should be permitted to be at a 
specified angle. The agency also asked whether, if the 
meaning of "perceptually upright" is clarified to 
expressly permit words as a whole to be placed at slight 
(specified) angles from the horizontal, a different 
requirement (e.g., one permitting lesser angles or no 
angle at all) is appropriate for cruise controls located 
on the steering wheel, given the fact that any angle 
will be altered during gradual turns (unlike the iden- 
tification of controls and displays located on the instru- 
ment panel). 

Finally, the agency noted that Standard No. lOl's 
"perceptually upright" requirement applies to a 
number of specified controls and displays in addition 
to the cruise control. The agency requested comments 
whether any of these other controls or displays should 
also be permitted on the steering wheel. 

Summary of Comments to 
Notice of Proposed Rulemaking. 

In response to its NPRM. the agency received five 
comments, all from manufacturers. The commenters 
were Chrysler, Ford, GM, Volkswagen, and Volvo. The 
manufacturers offered the following comments: 

Each of the five commenters supported the agency's 
first proposal, that identification for steering wheel 
mounted cruise controls be "perceptually upright" only 
when the steering wheel is centered, i.e., the vehicle 
has its wheels positioned to travel straight forward. 

Three commenters, Chrysler, Ford, and GM, opposed 
adopting the second alternative, to exclude steering 



wheel moimted cruise controls altogether from the 
"perceptually upright" requirement. Ford opposed this 
proposal because it was not aware of any data (similar 
to the case of the horn symbol) that "suggests a high 
degree of recognition for cruise control identification 
in all orientations." Chrysler made the same point as 
Ford, and added that "speed controls are normally 
multi-switch controls, whereas, the horn button is only 
one control and its location is usually on the steering 
wheel." 

With respect to the issue of whether, when the steer- 
ing wheel is centered, any identification which is at a 
slight angle should be considered perceptually upright 
and if so, at what angle such identification should not 
be considered "perceptually upright." only one 
manufacturer suggested a specific tolerance angle. In 
its comments, Volkswagen stated that the definition 
of "perceptually upright" should provide an angular 
tolerance range of 30 degrees. Volkswagen, however, 
did not explain the basis for its recommendation of 30 
degrees as a tolerance angle. Volvo generally stated 
its desire for a clearer definition of "perceptually 
upright" but did not provide any recommendations or 
guidelines. 

Chrysler, Ford, and GM opposed a redefinition of 
"perceptually upright" that would specify an angular 
tolerance. Ford and Chrysler's opposition was based 
on their lack of data or studies that would suggest 
criteria that would determine the limits of what could 
be construed as "perceptually upright." GM opposed 
any attempt to clarify "perceptually upright" with 
reference to specified angle from horizontal, stating 
that this would "result in greater confusion and create 
unreasonable difficulties in design and compliance with 
no offsetting benefits to motor vehicle safety." 

The only commenter on the question of whether 
angular tolerances should be permitted for cruise 
controls located on the steering wheel, Chrysler, stated 
that it did not believe regulating "perceptual upright- 
ness" by specifying a maximum angular position from 
the horizontal of steering wheel controls will increase 
the safety of using these controls. 

The last issue raised by the agency was whether, 
since Standard No. 101 's "perceptually upright" 
requirement applies to a number of specified controls 
and displays, any other specified controls or displays 
(in addition to cruise controls) in Standard No. 101 
should be permitted on the steering wheel. 

Volkswagen, Ford and GM stated that it would be 
appropriate not to restrict controls and displays which 
may be considered for placement on steering wheels. 
GM also commented that it was not aware of informa- 
tion establishing that motor vehicle safety is com- 
promised by "steering wheel-mounted control 
identifications which are not perceptually upright 
regardless of steering wheel orientation." GM noted 



PART 571; SlOl-PRE 48 



however, that all hub mounted controls should be 
subject to the "perceptually upright" requirement 
when the steering wheel is centered. 

In its comments, Chrysler suggested that other hand 
controls (e.g., lighting, windshield wiper) regulated by 
Standard No. 101 be permitted on the steering wheel. 
Chrysler concluded that manufacturers should be 
allowed to decide the practicality of symbols to be 
located on steering wheels. 

Agency Analysis of Issues and 
Adoption of Final Rule. 

All commenters favored the agency's proposal to re- 
quire cruise controls on steering wheels to appear to 
the driver perceptually upright only when the steer- 
ing wheel is dentered. No commenters opposed this 
proposed amendment. Further, with respect to the 
alternative proposed amendment to exclude steering 
wheel mounted cruise controls altogether from the 
perceptually upright requirement, the agency agrees 
with the concern expressed by some commenters that 
cruise control identification might not be easily recog- 
nizable in all orientations. For the reasons discussed 
in the NPRM, the agency is adopting the proposed 
amendment to require cruise controls on steering 
wheels to appear to the driver perceptually upright only 
when the steering wheel is centered. 

Another issue raised in the NPRM was whether this 
special provision for cruise controls should be extended 
to any other controls or displays. Currently, with 
certain exceptions, any identification for a control or 
display must appear to the driver "perceptually 
upright" at all times. The practical effect of requiring 
controls, displays, or identifications on a steering wheel 
to appear to the driver to be "perceptually upright" 
only when the steering wheel is centered would be that 
these other controls and displays could be placed on 
the steering wheel. 

In addressing this issue, most of the public com- 
menters stated that it would not be appropriate to 
restrict controls and displays which may be considered 
for placement on steering wheels. GM stated that it was 
not aware of any data showing that safety would be 
compromised by steering wheel mounted identifica- 
tions which are not "perceptually upright" regardless 
of steering wheel orientation. 

After considering this issue, the agency is concerned 
about the possible safety consequences of allowing all 
controls and displays on the rotating steering wheel. 
Some controls and displays, such as those for turn 
signals, appear to raise particular concerns. If the turn 
signal display were on the steering wheel, the relation- 
ship of the display to the side of the vehicle would be 
completely reversed when the steering wheel is turned 
180 degrees. This could potentially confuse the driver 
in the midst of a critical driving maneuver. If the turn 
signal control were on the steering wheel, it would also 
be reversed during a turn. 



Another concern for the agency is that even if a par- 
ticular control on a steering wheel did not pose safety 
problems from the standpoint of its identification being 
confusing to the driver, multiple controls on a steer- 
ing wheel may pose a problem. For example, if numer- 
ous controls are on the steering wheel, the headlamp 
or taillamp controls may be inadvertently turned off 
at night while the driver operates the radio or cruise 
controls. 

In light of its safety concerns, NHTSA has decided 
not to extend the special provision for cruise controls 
to other controls and displays at this time. The agency 
believes that such action should not be taken without 
further study of the possible safety consequences, 
including possible human factors research in this area. 

Another issue addressed in the NPRM was whether 
identification which is at a slight angle should be 
considered perceptually upright and, if so, at what 
angle such identification would not be considered 
perceptually upright. The agency requested comments 
on whether the meaning of perceptually upright should 
be clarified. 

After considering the comments, the agency has 
decided that it is unnecessary to amend Standard No. 
101 to clarify the meaning of "perceptually upright." 
First, the agency believes that the term is broad enough 
to permit identification at slight angles. NHTSA notes 
that persons reading a book or newspaper often hold 
it at a slight angle from the horizontal, yet perceive 
the writing to be upright. Thus, even though identifi- 
cation of controls or displays in a motor vehicle may 
be at a slight angle, a driver can perceive it to be 
upright. 

While the agency considered establishing a specific 
angular limit, the agency agrees with GM that such a 
limit could be difficult to interpret in light of the fact 
that identification of controls may be located on sur- 
faces made up of compound angles, surfaces that are 
curved, or surfaces that are in a horizontal plane. 
Hence, it could be difficult to devise an angular limit 
that is appropriate for all such surfaces. Moreover, 
while as discussed in the NPRM, certain control iden- 
tification in some cars is at a slight angle, the agency 
is imaware of any cars where the degree of angle makes 
it questionable whether the driver could perceive the 
identification as upright. NHTSA notes that while it 
is not establishing a specific angular limit at this time, 
it could consider doing so in the future if later car 
designs or research indicated a need to do so. 

Volvo requested that a clearer definition of "percep- 
tually upright" be provided in order to avoid uncertain- 
ties in the design of identification for controls. 
However, with the exception of the question of how 
the term applies to controls located on the steering 
wheel, which NHTSA has resolved by interpretation 
and by this rulemaking, the agency is unaware of any 



PART 571; SlOl-PRE 49 



evidence that the term has created difficulties for 
manufacturers in ensuring that their vehicles comply 
with Standard No. 101. The agency agrees with GM 
that time has proven that this term has not been a 
cause of concern. 

NHTSA has also decided not to establish any special 
angular limits for identification of cruise controls 
located on steering wheels. As discussed in the NPRM, 
any angle when the steering wheel is centered would 
be increased during turns. However, NHTSA believes 
that the steering wheel would be centered or almost 
centered when the driver will be observing cruise 
control identification. 

NHTSA finds, for good cause shown, that an earlier 
effective date of 30 days (rather than 180 days) after 
publication of this final rule in interest NHTSA's find- 
ing of good the Federal Register is in the public cause 
is based on the fact that the amendments to Standard 
No. 101 do not impose new requirements, but instead 
relax an existing requirement to provide additional 
flexibility. 

In consideration of the following. Federal Motor 
Vehicle Safety Standard No. 101 read as follows: 

(1) The last sentence of S5.2.1(a) is revised to read 
as follows: 
§ 571.101 Standard No. 101; Controls and displays 



S5.2 * * * 
S5.2.1 * * * 

(a) The identification shall, under the conditions of 
S6, be visible to the driver and, except as provided in 
S5.2.1.1. S5.2.1.2, and S5.2.1.3, appear to the driver 
perceptually upright. 

***** 

2. S5.2.1.3 is added to read as follows: 
S5.2.1.3 The identification of an automatic vehicle 
speed control located on the steering wheel, including 
the steering wheel hub and spokes, need not appear 
to the driver perceptually upright except when the 
vehicle, aligned to the manufacturer's specifications, 
has its wheels positioned for the vehicle to travel in a 
straight forward direction. 



Issued on: October 9, 1991. 



Jerry Ralph Curry 
Administrator 



56 F.R. 51845 
October 16, 1991 



PART 571; SlOl-PRE 50 



FEDERAL MOTOR VEHICLE SAFETY STANDARD NO. 101 



Controls and Displays 

(Docket No. 1-18; Notice 13) 



51. Scope. This standard specifies require- 
ments for the location, identification, and illumina- 
tion of motor vehicle controls and displays. 

52. Purpose. The purpose of this standard is to 
ensure the accessibility and visibility of motor vehi- 
cle controls and displays and to facilitate their 
selection under daylight and nighttime conditions, 
in order to reduce the safety hazards caused by the 
diversion of the driver's attention from the driving 
task, and by mistakes in selecting controls. 

53. Application. This standard applies to 
passenger cars, multipurpose passenger vehicles, 
trucks, and buses. 

54. Definitions. 

"Telltale" means a display that indicates, the ac- 
tuation of a device, a correct or defective function- 
ing or condition, or a failure to function. 

"Gauge" means a display that is listed in S5.1 or 
in Table 2 and is not a telltale. 

55. Requirements, (a) Except as provided in 
paragraph (b) of this section, each passenger car, 
multipurpose passenger vehicle, truck, and bus 
manufactured with any control listed in S 5.1 or in 
column 1 of Table 1, and each passenger car, 
multipurpose passenger vehicle and truck or bus 
less than 10,000 pounds GVWR with any display 
listed in S5.1 or in column 1 of Table 2, shall meet 
the requirements of this standard for the location, 
identification, and illumination of such control or 
display. 

(b) For vehicles manufactured before September 
1, 1987, a manufacturer may, at its option— 

(1) Meet the requirements in this standard to use 
identifying words or abbreviation or identifying 
symbol for a control by using those specified in 



Table 1(a) instead of Table 1. If none are 
specified in Table 1(a), none need be used for the 
control. 

(2) Meet the requirements in this standard to 
use identifying words or abbreviation or identify- 
ing symbol for a display by using those specified 
in Table 2(a) instead of Table 2. If none are 
specified in Table 2(a), none need by used for the 
display. 

S5.1 Location. [Under the conditions of S6, 
each of the following controls that is furnished 
shall be operable by the driver and each of the 
following displays that is furnished shall be visi- 
ble to the driver. Under conditions of S6, 
telltales are considered visible when activated. 52 
F.R. 33416— September 3, 1987— Effective: 
September 3, 1987)1 

Hand-Operated Controls 

(a) Steering wheel. 

(b) Horn. 

(c) Ignition. 

(d) Headlamp. 

(e) Tail lamp. 

(f) Turn signal. 

(g) Illumination intensity, 
(h) Windshield wiper. 

(i) Windshield washer. 

(j) Manual transmission shift lever, except 

transfer case. 

(k) Windshield defrosting, and defogging 
system. 

(1) Rear window defrosting and defogging 
system. 

(m) Manual choke, 
(n) Driver's sun visor. 



(Rev. 9/3/87) 



PART 571; S 101-1 



(o) Automatic vehicle speed system. 

(p) Highbeam. 

(q) Hazard warning signal. 

(r) Clearance lamps. 

(s) Hand throttle. 

(t) Identification lamps. 

Foot-Operated Controls 

(a) Service brake. 

(b) Accelerator. 

(c) Clutch. 

(d) Highbeam. 

(e) Windshield washer. 

(f ) Windshield wiper. 



Displays 



(a) 
(b) 



Speedometer. 
Turn signal. 



(c) Gear position. 

(d) Brake failure warning. 

(e) Fuel. 

(f) Engine coolant temperature. 

(g) Oil. 

(h) Highbeam. 

(i) Electrical Charge. 

S5.2 Identification. 

S5.2.1 Vehicle controls shall be identified as 
follows: 

(a) Except as specified in S5.2.1(b), any hand- 
operated control listed in column 1 of Table 1 that 
has a symbol designated for it in column 3 of that 
table shall be identified by either the symbol 
designated in column 3 (or symbol substantially 
similar in form to that shown in column 3) or the 
word or abbreviation shown in column 2 of that 
table. Any such control for which no symbol is 
shown in Table 1 shall be identified by the word or 
abbreviation shown in column 2. Words or symbols 
in addition to the required symbol, word or 
abbreviation may be used at the manufacturer's 
discretion for the purpose of clarity. Any such con- 
trol for which column 2 of Table 1 and /or column 3 
of Table 1 specifies "Mfr. Option" shall be iden- 
tified by the manufacturer's choice of a symbol, 
word or abbreviation, as indicated by that specifi- 
cation in column 2 and /or column 3. The identifica- 
tion shall be placed on or adjacent to the control. 
The identification shall, under the con- 
ditions of S6, be visible to the driver and, except as 



provided in S5.2.1.1, S5.2.1.2, [and 85.2.1.3] ap- 
pear to the driver perceptually upright. (56 F.R. 
51845— October 16, 1991. Effective: November 15, 
1991)1 

(b) S5.2.1(a) does not apply to a turn signal con- 
trol which is operated in a plane essentially parallel 
to the face plane of the steering wheel in its normal 
driving position and which is located on the left 
side of the steering column so that it is the control 
on that side of the column nearest to the steering 
wheel face plane. 

55.2.1 .1 The identification of the following need 
not appear to the driver perceptually upright: 

(a) A master lighting switch or headlamp and 
tail lamp control that adjusts control and display il- 
lumination by means of rotation, or of any other 
rotating control that does not have an off position. 

(b) A horn control. 

55.2.1 .2 The identification of a rotating control 
other than one described by S5.2.1.1 shall appear 
to the driver perceptually upright when the control 
is in the off position. 

[S5.2.1.3 The identification of an automatic 
vehicle speed control located on the steering 
wheel, including the steering wheel hub and 
spokes, need not appear to the driver perceptually 
upright except when the vehicle, aligned to the 
manufacturer's specification, has its wheels posi- 
tioned for the vehicle to travel in a straight for- 
ward direction. (56 F.R. 51845— October 16, 1991. Ef- 
fective: November 15, 1991)] 

S.5.2.2 Identification shall be provided for each 
function of any automatic vehicle speed system 
control and any heating and air conditioning 
system control, and for the extreme positions of 
any such control that regulates a function over a 
quantitative range. If this identification is not 
specified in Tables 1 or 2, it shall be in word or 
symbol form unless color coding is used. If color 
coding is used to identify the extreme positions of a 
temperature control, the hot extreme shall be iden- 
tified by the color red and the cold extreme by the 
color blue. 

Example 1 A slide lever controls the 
temperature of the air in the vehicle heating 
system over a continuous range, from no heat 
to maximum heat. Since the control regulates a 
single function over a quantitative range, only 
the extreme positions require identification. 



(Rev. 10/16/91) 



PART 571; S 101-2 



Example 2 A switch has three positions, for 
heat, defrost, and air conditioning. Since each 
position regulates a different function, each 
position must be identified. 

S5.2.3 [Any display located within the 
passenger compartment and listed in column 1 of 
Table 2 that has a symbol designated in column 4 of 
that table shall be identified by either the symbol 
designated in column 4 (or symbol substantially 
similar in form to that shown in column 4) or the 
word or abbreviation shown in column 3. Addi- 
tional words or symbols may be used at the 
manufacturer's discretion for the purpose of clar- 
ity. Any telltales used in conjunction with a gauge 
need not be identified. The identification required 
or permitted by this section shall be placed on or 
adjacent to the display that it identifies. The iden- 
tification of any display shall, under the conditions 
of S6, be visible to the driver and appear to the 
driver perceptually upright. 

S5.3 Illumination. 

55.3.1 Except for foot-operated controls or 
hand-operated controls mounted upon the floor, 
floor console, or steering column, or in the wind- 
shield header area, the identification required by 
§ 5.2.1 or § 5.2.2 of any control listed in column 1 
of Table 1 and accompanied by the word "yes" in 
the corresponding space in column 4 shall be 
capable of being illuminated whenever the 
headlights are activated. However, control iden- 
tification for a heating and air-conditioning system 
need not be illuminated if the system does not 
direct air directly upon windshield. If a gauge is 
listed in column 1 of Table 2 and accompanied by 
the word "yes" in column 5, then the gauge and its 
identification required by § 5.2.3 shall be 
illuminated whenever the ignition switch and /or 
the headlamps are activated. Controls, gauges, and 
their identifications need not be illuminated when 
the headlamps are being flashed. A telltale shall 
not emit light except when identifying the mal- 
function or vehicle condition for whose indication it 
is designed or during a bulb check upon vehicle 
starting. 

55.3.2 Each telltale shall be of the color shown 
in column 2 of Table 2. The identification of each 
telltale shall be in a color that contrasts with the 
background. 

55.3.3 (a) Means shall be provided for making 
controls, gauges, and the identification of those 



items visible to the driver under all driving condi- 
tions. 

(b) The means for providing the required 
visibility— 

(1) Shall be adjustable, except as provided in 
S5.3.3(d), to provide at least two levels of 
brightness, one of which is barely discernable to 
a driver who has adapted to dark ambient road- 
way conditions. 

(2) May be operable manually or automatically, 
and 

(3) May have levels of brightness at which 
those items and their identification are not 
visible. 

(c) Effective September 1, 1989, if the level of 
brightness is adjusted by automatic means to a 
point where items or their identification are not 
visible to the driver, a means shall be provided to 
enable the driver to restore visibility. 

(d) For a vehicle manufactured before 
September 1, 1989, the requirements of 
S5. 3. 3(b)(1) shall not apply to any gauge during the 
actuation of a telltale which shares a common light 
source with the gauge. 

5.3.4 (a) Means shall be provided that are 
capable of making telltales and their identification 
visible to the driver under all driving conditions. 

(b) The means for providing the required visi- 
bility may be adjustable manually or automatically, 
except that the telltales and identification for 
brakes, highbeams, turn signals, and safety belts 
may not be adjustable under any driving condition 
to a level that is invisible. 

S5.3.5 [Any source of illumination within the 
passenger compartment which is forward of a 
transverse vertical plane 4.35 inch (110.6 mm) 
rearward of the mainkin "H" point with the 
driver's seat in its rearmost driving position, which 
is not used for the controls and displays regulated 
by this standard, which is not a telltale, and which 
is capable of being illuminated while the vehicle is 
in motion, shall have either (1) light intensity which 
is manually or automatically adjustable to provide 
at least two levels of brightness, (2) a single inten- 
sity that is barely discernible to a driver who has 
adapted to dark ambient roadway conditions, or (3) 
a means of being turned off. This requirement does 
not apply to buses that are normally operated with 
the passenger compartment illuminated. 



(Rev. 9/3/87) 



PART 571; S 101-3 



Table 1 is amended by adding the word "Lights" 
to column 2 as identifying words or abbreviation 
for Master Lighting Switch control, by adding the 
word "Horn" to column 2 as identifying words or 
abbreviation for Horn control, by adding the word 
"Hazard" to column 2 as identifying words or ab- 
breviation for Hazard Warning Signal control, by 
adding the words "Wiper or Wipe" to column 2 as 
identifying words or abbreviation for Windshield 
Wiping System control, by adding the words 
"Washer or Wash" to column 2 as identifying 
words or abbreviation for Windshield Washing 
System control, by adding the words "Wash- Wipe 
or Washer- Wiper" to column 2 as identifying 
words or abbreviation for Windshield Washing and 
Wiping Combined control, by adding the word 
"Fan" to column 2 as identifying words or ab- 
breviation for Heating and/or Air Conditioning 
Fan control, by adding the words "Defrost, Defog 
or Def to column 2 as identifying words or 
abbreviation for Windshield Defrosting and 
Defogging System control, by adding the words 
"Rear Defrost, Rear Defog, Rear Def, or R-Def" 
to column 2 as identifying words or abbreviation 
for Rear Window Defrosting and Defogging 
System control, and by adding the words "Marker 
Lamps or MK Lps" to column 2 as identifying 
words or abbreviation for identification. Side 
Marker and or Clearance Lamps control. (52 F.R. 
33416 September 3, 1987— Effective: September 3, 
1987)] 



(b) Except as provided in S5.4(e), the telltales 
listed in Table 2 shall be displayed at the initiation 
of any underlying condition. 

(c) When the underlying condition exists for ac- 
tuation of two or more messages, the messages 
shall be either— 

(1) repeated automatically in sequence, or 

(2) indicated by visible means and capable of 
being selected by the driver for viewing. 

(d) Messages may be cancellable automatically 
or by the driver. 

(e) The safety belt telltale must be displayed and 
visible during the time specified in S7.3 of 
Standard No. 208. 

S6. Conditions. The driver is restrained by the 
crash protection equipment installed in accord- 
ance with the requirements of § 571.208 of this 
part (Standard No. 208), adjusted in accordance 
with the manufacturer's instructions. 



43 F.R. 27541 
June 26, 1978 



(Rev. 9/3/87) 



PART 571; S 101-4 



TABLE 1 
Identification and Illumination of Controls 



Column 1 


Column 2 


Column 3 


Column 4 


Hand Operated Controls 


Identifying Words 
or Abbreviation 


Identifying 
Symbol 


Illumination 


Master Lighting 
Switch 




-pr 








Headlamps and 
Tail lamps 


(Mfr. Option)' 


(Mfr. Option)' 






Horn 




hy' 








Turn Signal 




**: 








Hazard Warning 
Signal 




A' 


Yes 




Windshield Wiping 
System 




V 


Yes 




Windshield Washing 
System 




<& 


Yes 




Windshield Washing 
and Wiping Combined 






Yes 




Heating and/or Air 
Conditioning Fan 




H.^ 


Yes 




Windshield Defrosting 
and Defogging System 




<^ 


Yes 




Rear Window Defrosting 
and Defogging System 








Yes 


4il 






7)5 




Identification, Side 

Marker and or Clearance 

Lamps 






Yes 




Manual Choke 


Choke 










Engine Start 


Engine Start' 










Engine Stop 


Engine Stop' 




Yes 




Hand Throttle 


Throttle 










Automatic Vehicle Speed 


IMfr Option) 




Yes 




Heating and Air 

Conditioning 

System 


(Mfr. Option) 


(Mfr. Option) 


Yes 



' Use when engine control is separate from the key locking system. 

' Separate identification not required if controlled by master lighting switch 

' The pair of arrows is a single symbol. When the controls for left and right turn operate independently, 

however, the two arrows may be considered separate symbols and be spaced accordingly 
' Identification not required for vehicles with a GVWR greater the 10.000 lbs., or for narrow ring-type controls. 
' Framed areas may be filled. 

PART 571; S 101-5 



TABLE 1A 
Identification and Illumination of Controls 



Column 1 


Column 2 


Column 3 


Column 4 


Hand Operated Controls 


Identifying Words or Abbreviation 


Identifying Symbol 


Illumination 


Headlamps and 
Tail Lamps 


Lights 


iO '' 




Turn Signal 




<p^ 




Hazard Warning 
Signal 


Hazard 


A ' 


Yes 


Clearance Lamps 
System 


Clearance Lamps or CI Lps 


-M ' ' 


Yes 


Windshield Wiping 
System 


Wiper or Wipe 


V 


Yes 


Windshield Washing 
System 


Washer or Wash 
[or Washer-Wiper] 


^ 


Yes 


Windshield Washing and 
Wiping Combined 


Wash-Wipe 


^ 


Yes 


Heating and/or Air 
Conditioning Fan 


Fan 


§§ 


Yes 


Windshield Defrosting & 
Defogging System 


Defrost, Defog or Def 


<w 


Yes 


Rear Window Defrosting 
and Defogging System 


Rear Defrost, Rear Defog 
Rear Def [or R-Def] 




Yes 


l¥ 


))) 


Engine Start 


Engine Start' 






Engine Stop 


Engine Stop' 




Yes 


Manual Choke 


Choke 






Hand Throttle 


Throttle 






Automatic Vehicle Speed 


(Mfg Option) 




Yes 


Identification Lamps 


Identification Lamps or Lps 




Yes 


Heating and Air 
Conditioning System 


(Mfg Option) 




Yes 



1. Use when engine control is separate from the key locking system. 

2. Use also when clearance, identification, parking and/or side marker lamps are controlled with the 
headlamp switch. 

3. Use also when clearance lamps, identification lamps and/or side marker are controlled with one 
switch other than the headlamp switch. 

4. Framed areas mav be filled. 



(Rev. 2/3/87) 



PART 571; S 101-6 



TABLE 2 
Identification and Illumination of Displays 



Column 1 


Column 2 


Column 3 


Column 4 


Column 5 


Display 


Telltaie 
Color 


Identifying Words 
or Abbreviation 


Identifying 
Symbol 


Illumination 


Turn Signal 
Telltale 


Green 


Fasten Seat Belts 
Also see FMVSS 208 


<^'^; 






Hazard Warning 
Telltale 




Also see 
FMVSS 108 


a: 






Seat 

Belt 

Telltale 




Also see 
FMVSS 208 •''' 


'XT^ '-'• ^Tr 






Fuel Level 
Telltale 




Fuel 


BB 


Yes 


Gauge 






Oil Pressure 
Telltale 




Oil 


•fcT-. 




Yes 


Gauge 






Coolant Temperature 
Telltale 




Temp 


J- 




Yes 


Gauge 






Electrical Charge 
Telltale 




Volts, Cfiarge 
or Amp 






^ 


Yes 


Gauge 








Highbeam 
Telltale 


Blue or 
Green 


Also see 
FMVSS 108 


ED' 






Malfunction in 
Anti-Lock or 


Yellow 


Antilock, Anti-lock, for 

ABSl Also see 

FMVSS 105 








Brake System 




Brake. Also 
see FMVSS 105 










Brake Air Pressure 
Position Telltale 




Brake Air Also 
see FMVSS 121 










Speedometer 




MPH^ 




Yes 




Odometer 




3 










Automatic Gear 
Position 




Also see 
FMVSS 102 




Yes 







The pair of arrows is a single symbol. When the indicator for left and right turn operate independently, however, the two arrows 
will be considered separate symbols and may be spaced accordingly. 

Not required when arrows of turn signal tell-tales that otherwise operate independently flash simultaneously as hazard warning 

tell-tale 

If the odometer indicates kilometers, then "KILOMETERS" or "km" shall appear, otherwise, no identification is required. 
^ Red can be red-orange. Blue can be blue-green. 
^ If the speedometer is graduated in miles per hour and in kilometers per hour, the identifying words or abbreviations shall be 

"MPH and km h" in any combination of upper or lower case letters. 
* Framed areas may be filled. 
'The color of the telltale required by 84 5 3 3 of Standard No. 208 is red: the color of itie telltale required by S7 3 of Standard 

No 208 IS not specified. 



(Rev. 5/28/87) 



PART 571; S 101-7 



TABLE 2A 
Identification and Illumination of Internal Displays 



Column 1 


Column 2 


Column 3 


Column 4 


Column 5 


Display 


Tell-Tale 
Color 


Identifying Words or 
Abbreviation 


Identifying Symbol 


Illuminate 


Turn Signal 
Tell-Taie 


Green 


Fasten Seat Belts 
Also see FMVSS 208 


<?<> ; 




Hazard Warning 
Tell-Tale 


Red4 


Also see 
FMVSS 108 


A : 




Seat Belt 
Tell-Tale 


Red"! 


Also see 
FMVSS 208 


4 




Fuel Level, Tell-Tale 


Yellow 


Fuel 


— 


^ 




Gauge 




Fuel 


Yes 


Oil Pressure 
Tell-Tale 


Red4 


Oil 


^G^i 




Gauge 




Oil 


Yes 


Coolant Temperature 
Tell-Tale 


Red-* 


Temp 


-t 




Gauge 




Temp 


Yes 


Electrical Charge 
Tell-Tale 


Red-* 


Volts, Charge or Amp 






- *\ 


Gauge 




Volts, Charge or Amp 


Yes 




Speedometer 




MPH" 




Yes 


Odometer 




^ 






Automatic Gear 
Position 




Also see 
FMVSS 102 




Yes 


High Beam 
Tell-Tale 


Blue or 
Oeeii'' 


Also see 
FMVSS 108 


iO . 




Brake Air Pressure 
Position, Tell-Tale 


Red-* 


Brake Air Also see 
FMVSS 121 






Malfunction in 
Anti-Lock or 


Yellow 


Anti-Lock Also see 
FMVSS 105-75 






Brake System 


Red-" 


Brake Also see 
FMVSS lOiVTri 







1. The pair of arrows is a single symbol. Mien the indicator for left and right turn operate independently, 
however, the two arrows will be considered separate symbols and may be spaced accordingly. 

2. Not required when arrows of turn signal tell-tales that otherwise operate independently flash simul- 
taneously as hazard warning tell-tale. 

3. If the odometer indicates kilometers, then •■KILOMETERS" or "km" shall appear otherwise, no 
identification is required. 

4. Red can be red-orange. Blue can be blue-green. 

5. Framed areas may be filled. 

6. If the speedometer is graduated in miles per hour and in kilometers per hour, the identifying words or 
abbreviations shall be "MPH and km/h" in any combination of upper or lower ease letters. 



(Rev. 6/4/85) 



PART 571; S 101-8 



PREAMBLE TO AN AMENDMENT TO FEDERAL MOTOR VEHICLE 
SAFETY STANDARD NO. 102 

Transmission Shift Lever Sequence, Starter Interlock, and Transmission Braking Effect 

(Docket No. 88-16; Notice 2) 
RIN: 2127-AC-54 



ACTION: Final rule. 

SUIVIMARY: Standard No. 102 has long required the 
"identification of shift lever positions of automatic 
transmissions" to be "permanently displayed in view 
of the driver." This notice amends the standard for 
automatic transmission vehicles which have a shift 
lever position which puts the transmission in park. 
For these vehicles, the requirement for "permanent 
display" is replaced with a requirement that iden- 
tification of automatic transmission shift lever posi- 
tions be displayed in view of the driver whenever any 
of the following conditions exist: (a) the ignition is in 
a position where the transmission can be shifted; (b) 
the transmission is not in park. The new require- 
ments will facilitate the use of electronic displays, 
while ensuring that the information in question is 
displayed at all times when it may be needed for 
safety. 

DATES: The amendments made by this rule are ef- 
fective August 10, 1989. 

SUPPLEMENTARY INFORMATION: One of the stated 
purposes of Standard No. 102, Transmission Shift 
Lever Sequence, Starter Interlock, and Transmission 
Braking Effect, is to reduce the likelihood of shifting 
errors. Since 1967, section S3. 2 of the standard has 
required "identification of shift lever positions of 
automatic transmissions" to be "permanently 
displayed in view of the driver." NHTSA has inter- 
preted the term "positions" to include both the posi- 
tion of the gears in relation to each other and the gear 
position actually selected. NHTSA has interpreted the 
requirement that identification be "permanently 
displayed in view of the driver" to require a display 
whenever there is a driver in the driver's seating posi- 
tion, even if the ignition is not turned on. 

On August 25, 1988, NHTSA published in the 
Federal Register (53 FR 32409) a notice of proposed 
rulemaking (NPRM) to amend Standard No. 1902. As 
discussed in the NPRM, Chrysler and GM had sub- 
mitted petitions for rulemaking requesting that sec- 
tion S3. 2 of the standard be amended to "permit" or 
"more clearly allow" the use of electronic displays of 
automatic transmission shift lever positions. (These 



displays are often called PRNDL displays, the 
acronym PRNDL referring to the following gear posi- 
tions: park, reverse, Aieutral, drive, and Zow.) Chrysler 
argued that the requirement for permanent display 
of the PRNDL was design restrictive and prevented 
the use of electronics. That company stated that since 
an electronic display requires electrical current for 
activation, a permanent and constantly activated 
display would drain the vehicle's battery in a short 
period of time. Chrysler stated that fifteen minutes 
is the maximum amount of time that it can allow an 
electronic display to draw energy from the battery of 
a parked vehicle. 

Both Chrysler and GM argued that the use of elec- 
tronic PRNDL displays can offer several benefits, as 
compared to conventional mechanical displays. These 
include more precise indication of the selected gear, 
visibility which does not depend on ambient light 
and/or headlamp activation, designs with improved 
human factors characteristics, and improved 
customer satisfaction through product distinction and 
innovation. 

In light of Chrysler's and GM's petitions for rule- 
making and changed technology since the require- 
ment for "permanent display" was promulgated, 
NHTSA reexamined the issue of whether permanent 
display of PRNDL information is necessary for safety. 
The agency explained in the NPRM that it had ten- 
tatively determined that a less stringent requirement 
could maintain the safety aspects of section S3. 2 while 
facilitating the use of electronic technology. 

As indicated above, the stated purpose of the re- 
quirement for permanent display of PRNDL informa- 
tion is to reduce the likelihood of shifting errors. 
NHTSA stated in the NPRM that, with respect to a 
driver making a mistake in shifting gears, it believed 
that this purpose could be accomplished by requiring 
PRNDL information to be displayed whenever the ig- 
nition is in a position where it is possible for the driver 
to shift the transmission. Another safety concern 
about shifting errors is the possibility that a driver 
will leave a vehicle believing that it is in park when 
it is not. The agency stated in the NPRM that, with 
respect to the contribution that a PRNDL display can 



PART 571; S102-PRE 1 



make to reducing the likelihood of such an occurrence, 
it believed that purpose could be accomplished by re- 
quiring PRNDL information to be displayed when- 
ever the transmission is not in park. 

NHTSA therefore proposed to amend Standard No. 
102 by replacing section S3.2's requirement for 
"permanent display" with a requirement that iden- 
tification of shift lever positions of automatic 
transmissions, including both the position of the gears 
in relation to each other and the position selected, be 
displayed in view of the driver when either of the 
following conditions exists: (A) the ignition is in a 
position where the transmission can be shifted, or (B) 
the transmission is not in park. Under the proposal, 
however, such display would not be required when the 
ignition is in a position that is used only to start the 
vehicle. The only time the ignition is in that position 
is momentarily during the starting of the vehicle, and 
full battery power may be needed at that time to start 
the vehicle. NHTSA noted that the proposed require- 
ments focused on the vehicle conditions where the 
agency believed there is a safety need for PRNDL in- 
formation to be displayed to the driver. 

NHTSA explained that, as a practical matter, 
manufacturers choosing to avail themselv^ of the in- 
creased flexibility offered by the proposed re- 
quirements would likely use an electronic PRNDL 
display coupled with a transmission shift interlock 
system. The interlock system could be designed to pre- 
vent the transmission from being shifted when the 
vehicle is parked, i.e., when the transmission is in 
park and the ignition is in the lock position. The 
PRNDL information would not be required to be 
displayed in this situation, since the transmission 
would be in park and the ignition would be in a posi- 
tion where the transmission could not be shifted. 
There would thus not be a problem of the vehicle's 
battery being drained as a result of a driver's leaving 
the vehicle with the PRNDL display illuminated. 

NHTSA also noted that the use of transmission shift 
interlock systems could result in safety benefits 
unrelated to the display of PRNDL information. In 
a separate rulemaking concerning Standard No. 114, 
the agency has proposed requirements that would 
have the effect of requiring transmission shift in- 
terlock systems for automatic transmission vehicles 
(i.e., the ignition key-locking system shall not permit 
removal of the key except when the transmission 
lever is in the park position). See 53 FR 1-1105, April 
5, 1988. That proposal was issued in light of a safety 
concern about the rolling away of some automatic 
transmission vehicles when they are parked on 
slanted surfaces with the ignition key removed and 
the parking brake not applied. The rollaway accidents 
occur Tjecause the ignition key can be removed, but 
the gear shift lever can be left in neutral or in gear, 
or it can be inappropriately or inadvertently shifted 



out of park by another occupant, typically an unat- 
tended child. 

NHTSA received seven comments on the NPRM 
concerning Standard No. 102. Both of the petitioners 
supported the proposal, although GM's support was 
limited to vehicles other than heavy duty vehicles. 
GM stated that it supports the agency's view that the 
proposed requirements would preserve the safety 
benefits of section S3. 2 while facilitating the use of 
electronic technology. That company expressed con- 
cern, however, that the proposed amendments would 
not provide the same flexibility for heavy duty trucks. 
GM stated that the increased flexibility is only 
available when the electronic PRNDL is used in con- 
junction with a transmission interlock system which 
precludes shifting the transmission whenever it is in 
the park position and the ignition is in the lock or 
accessory position. According to GM, however, its 
heavy duty trucks with GVWR in excess of 10,000 
pounds do not have a park position or transmission 
interlock system. That company recommended a dif- 
ferent amendment for heavy duty vehicles. Chrysler 
stated that while the proposed requirements were 
somewhat different than it had recommended in its 
petition, the proposal would achieve the desired 
objective. 

Like GM, Ford expressed support for the proposal, 
while recommending different requirements for 
medium and heavy duty trucks. Ford stated that 
automatic transmission-equipped medium and heavy 
duty trucks do not have a shift lever park position 
and urged that a provision be made for these vehicles 
to provide the same flexibility for use of electronic 
display of shift lever positions as in vehicles with a 
shift lever park position. The Motor Vehicle Manufac- 
turers Association (MVMA) and Navistar Interna- 
tional also recommended that different requirements 
be established for medium and heavy duty vehicles. 

Two manufacturers, Volkswagen and Austin Rover, 
supported the intent of the proposal to permit addi- 
tional design flexibility but argued that the proposal 
did not go far enough. Volkswagen expressed concern 
that the proposed requirements could increase the 
potential for unwanted battery drain. That company 
noted that the NPRM had cited the possibility of bat- 
tery ^rain occurring if the key remains in the igni- 
tion and the vehicle is not in park. Volkswagen 
argued that existing NHTSA requirements along 
with a shift interlock would adequately protect 
against this type of problem without increasing the 
potential for unwanted battery drain and urged the 
agency to modify its proposal to accommodate such 
systems. That company explained its position as 
follows: 

"If a driver leaves a vehicle without removing the 
key from the ignition, FMVSS 114 S4.5 requires 



PART 571; S102-PRE 2 



that a warning be provided to the driver. This war- 
ning is intended to attract the driver's attention 
to the fact that the key is left in the ignition. A 
driver who responds to this warning, who has not 
placed the transmission in park, will not be able 
to remove the key if the vehicle is equipped with 
a shift interlock. Hence, the driver's attention will 
be attracted to the factor prohibiting removal of 
the key and the transmission will be placed in 
park in order to remove the key. In addition, 
FMVSS 102 S3. 1.3 requires that the engine 
starter be inoperative when the transmission shift 
lever is in a forward or reverse drive position. 
Therefore a driver who ignores the signal and 
returns later to start the vehicle will not be able 
to do so unless the transmission is in park or 
neutral. A driver who left the vehicle in park or 
neutral, will see the electronic PRNDL display 
just before and immediately after safely starting 
the vehicle. A driver who left the vehicle in drive 
or reverse will see the display when an attempt 
is made to start the vehicle and it will not res- 
pond." 

Volkswagen also stated that all of its currently pro- 
duced Audi vehicles, with automatic transmissions, 
are equipped with an audible warning to the driver 
if the transmission is left in a position other than 
park. That company requested that the agency allow 
this design alternative. Austin Rover argued that 
there are alternative systems to the "General Motors 
system" described in the NPRM which could be used 
without any reduction in the level of safety offered 
by the present standard and recommended require- 
ments that would permit such systems. That company 
suggested that complete PRNDL information is 
needed only when the vehicle is capable of powered 
motion, and that in situations where the vehicle is 
not capable of powered motion, the driver only needs 
to be able to determine whether the park position has 
been selected. 

After carefully considering the comments, NHTSA 
has decided to issue a final rule along the lines of the 
proposal for automatic transmission vehicles which 
have a shift lever park position. The agency has con- 
cluded that the amended requirements will maintain 
the safety aspects of section S3.2 while facilitating the 
use of electronic technology for passenger cars and 
other light vehicles. 

NHTSA recognizes the concerns expressed by 
several commenters that the amended requirements 
may not facilitate the use of electronic technology in 
medium and heavy duty vehicles, since those vehicles 
do not have a shift lever park position. However, the 
requirements recommended by those commenters are 
significantly different than those proposed in the 
NPRM. The agency therefore plans to address that 



issue in a separate rulemaking. NHTSA notes that 
Volkswagen suggested in its comment that Standard 
No. 102 be amended to provide greater flexibility for 
manual transmission pattern displays as well as for 
automatic transmission shift lever position displays. 
The agency plans to address that issue in the separate 
rulemaking. For now, NHTSA is maintaining the ex- 
isting requirements both for automatic transmission 
vehicles which do not have a park position and for 
manual transmission vehicles. However, the agency 
is amending the language requiring that information 
be "permanently displayed in view of the driver" to 
reflect its past interpretations that display is required 
whenever there is a driver in the driver's seating 
position. 

As discussed above, in developing its August 1988 
proposal, NHTSA focused on the vehicle conditions 
where it believes there is a safety need for PRNDL 
information, i.e., whenever it is possible for the driver 
to shift the transmission and whenever the transmis- 
sion is not in park. The agency does not believe that 
Volkswagen or Austin Rover demonstrated either a 
need for further flexibility for purposes of facilitating 
electronic technology or that their suggested alter- 
native amendments would ensure that PRNDL infor- 
mation is always available when needed. 

With respect to Volkswagen's comment concerning 
possible battery drain, NHTSA notes that the NPRM 
specifically requested comment on this issue. Only 
two commenters directly addressed the issue, 
Volkswagen and Chrysler. While Volkswagen ex- 
pressed concern that the proposed requirements could 
increase the potential for unwanted battery drain, 
Chrysler stated the following: 

"We do not believe that a problem will be created 
for motorists if the PRNDL display is activated 
when the ignition switch is in the 'off position. 
In fact, it should encourage drivers to place the 
transmission in 'park' and turn the ignition 
switch to the lock position in order to avoid bat- 
tery rundown. Since the agency's proposal allows 
the PRNDL display to be off when the transmis- 
sion is in 'park' and the ignition switch is in the 
'lock' position, leaving the key in the ignition 
switch for an extended period, as often happens 
in parking lots and garages, poses no 
problem . . . . " 

While GM and Ford did not directly address the 
issue of possible battery drain, NHTSA believes that 
their general support of the proposal and statements 
that the proposal will facilitate the use of electronic 
technology indicate that they do not consider the issue 
to present a significant problem for their customers. 

In the NPRM, NHTSA noted that the possibility of 
battery drain occurring when the key remains in the 



PART 571; S102-PRE 3 



ignition and the vehicle is not in park is not unlike 
other situations, such as leaving headlamps or a radio 
on for extended periods. The agency also noted that 
manufacturers could provide warnings to the driver 
before the battery is drained to the point that it could 
no longer start the vehicle. In the absence of evidence 
indicating that battery drain would be a significant 
actual problem for drivers, as opposed to a theoretical 
possibility, NHTSA does not believe that further flex- 
ibility should be provided at the expense of ensuring 
that PRNDL information is available when needed. 
The agency also believes that the chances of this prob- 
lem occurring would be much lower than for a driver 
leaving lights on. That problem tj^pically occurs when 
a driver forgets to turn off lights when parking dur- 
ing daylight or under brightly lit conditions. 
However, while a driver typically needs to turn off 
a vehicle's lights separately, that would not be true 
for PRNDL displays. The potential problem of battery 
drain occurring from the PRNDL display would be 
limited to the rare situation where the driver parks 
the vehicle not only leaving the key in the ignition 
but also with the vehicle not in park. 

Volkswagen suggested that a driver who responds 
to an audible warning that the key is left in the igni- 
tion would not be able to remove the key if the vehi- 
cle is equipped with a shift interlock, and thereby 
would have his or her attention attracted to the fac- 
tor prohibiting removal of the key. That company 
stated that the transmission would be placed in park 
in order to remove the key. NHTSA believes, how- 
ever, that some drivers who choose to ignore the audi- 
ble warning about the key might wish to check the 
PRNDL display as to whether the vehicle is in park, 
as part of ensuring that the vehicle is securely parked, 
or simply notice the PRNDL display. Also, in the 
situation posited by Volkswagen, the PRNDL display 
might assist the driver in comprehending what factor 
was preventing removal of the key, thereby making 
it more likely that the driver would place the vehicle 
in park. 

Volkswagen also suggested that manufacturers 
should be permitted the alternative of providing an 
audible warning to the driver if the transmission is 
left in a position other than park. While manufac- 
turers are free to provide such warnings, NHTSA does 
not believe that the warning should be a substitute 
for a PRNDL display that advises the driver that the 
vehicle is not in park. Drivers may not understand 
the meaning of the audible warning and are likely 
to check the PRNDL display if they are in doubt as 
to whether the vehicle is in park. 

As indicated above, Austin Rover suggested that 
complete PRNDL information is needed only when 
the vehicle is capable of powered motion, and that in 
situations where the vehicle is not capable of powered 
motion, the driver only needs to be able to determine 



whether the park position has been selected. NHTSA 
disagrees. First, whenever a vehicle is not already in 
park, the agency believes that a driver needs complete 
PRNDL information in order to be able to easily shift 
the vehicle to park. The issue of whether the vehicle I 
is then capable of powered motion or not is irrelevant 
to that point. Second, a driver might choose to shift 
gears and move a vehicle for short distances without 
the engine on. In this situation, where the vehicle is 
not capable of powered motion, the agency believes 
that the driver needs full PRNDL information in 
order to safely move the vehicle. 

Volkswagen stated that the proposal presented one 
aspect of ambiguity, whether the functions of two 
PRNDL displays can be used together to demonstrate 
compliance with the standard. That company asked 
whether an electronic display on the instrument 
panel could be used to show the gear position selected 
and an embossed display on the floor console be used 
to show the position of the gears in relation to each 
other. 

Section S3.2's current requirement that "(i)den- 
tification of shift lever positions of automatic 
transmissions ... be permanently displayed in view 
of the driver" does not expressly require the specified 
information to be provided in a single display. 
However, NHTSA believes that requirement was 
written with the assumption that the specified infor- 
mation would be provided in a single display, and that 
current vehicle designs reflect that assumption. The I 
agency is concerned that if the information is not pro- 
vided in a single display, the standard may be less 
effective in achieving its purpose of reducing the 
likelihood of shifting errors. NHTSA plans to address 
this issue in the separate rulemaking cited above. 

Since the amendments adopted today impose no 
new requirements but instead increase manufacturer 
flexibility, NHTSA has determined that an effective 
date of 30 days after publication in the Federal 
Register is in the public interest. 

In consideration of the foregoing, 49 CFR Part 571 
is amended as follows: S3. 1.4 is added to § 571.102 
to read as follows: 

S3. 1.4 Identification of shift lever positions. 

53. 1.4.1 Except as specified in S3. 1.4.3, if the 
transmission shift lever sequence includes a park 
position, identification of shift lever positions, in- 
cluding the positions in relation to each other and the 
position selected, shall be displayed in view of the 
driver whenever any of the following conditions exist: 

(a) The ignition is in a position where the transmis- 
sion can be shifted. 

(b) The transmission is not in park. 

53.1.4.2 Except as specified in S3. 1.4.3, if the 
transmission shift lever sequence does not include a 
park position, identification of shift lever positions, 
including the positions in relation to each other and 



PART 571; S102-PRE 4 



the position selected, shall be displayed in view of the 
driver at all times when a driver is present in the 
driver's seating position. 

S3. 1.4.3 Such information need not be displayed 
when the ignition is in a position that is used only 
to start the vehicle. 

3. S3. 2 is revised to read as follows: 

S3. 2 Manual transmissions. Identification of the 
shift lever pattern of manual transmissions, except 
three forward speed manual transmissions having the 
standard "H" pattern, shall be displayed in view of 
the driver at all times when a driver is present in the 
driver's seating position. 

Issued on July 5, 1989. 

Jeffrey R. Miller 
Acting Administrator 

54 F.R. 29041 
July 11, 1989 



PART 571; S102-PRE 5-6 



PREAMBLE TO AN AMENDMENT TO FEDERAL MOTOR VEHICLE 
SAFETY STANDARD NO. 102 

Transmission Shift Lever Sequence, Starter interloclt, and Transmission Braking Effect 

(Docl(et No. 88-16; Notice 4) 
RIN: 2127AC-75 



ACTION: Final rule. 

SUIVIMARY: Standard No. 102 currently requires per- 
manent display of gear position information for auto- 
matic transmission vehicles without a gear shift lever 
park position. This final rule replaces that requirement 
with one that requires display of gear position infor- 
mation only when the ignition is in a position in which 
the engine is capable of operation. The purpose of this 
amendment, which affects medium and heavy duty 
vehicles, is to facilitate the use of electronic technology. 
This final rule also amends the standard to require, for 
all automatic transmission vehicles, that full gear 
^position information, i.e., identification of shift lever 
'positions, including the position of the gears in rela- 
tion to each other and the gear position selected, be 
provided in a single location. 

EFFECTIVE DATES: The amendment to Standard 
No. 102's requirement for permanent display of gear 
position information for automatic transmission 
without a gear shift lever park position is effective 
April 25, 1991. The amendment adding § 3.1.4.4 to re- 
quire, for all automatic transmission vehicles, that full 
gear position information be displayed in a single 
location is effective September 23, 1991. 

SUPPLEMENTARY INFORIVIATION: 

One of the stated purposes of Standard No. 102, 
Transmission Lever Sequence, Starter Interlock, and 
Transmission Braking Effect, is to reduce the likeli- 
hood of shifting errors. For many years, section S3.2 
of the standard required identification of shift lever 
positions of all automatic transmission vehicles to be 
permanently displayed in view of the driver. 

On July 11, 1989, NHTSA published in the Federal 
Register (53 F.R. 32409) a final rule amending Stand- 
ard No. 102 for vehicles which have a shift lever posi- 
tion which puts the transmission in park. For those 
vehicles, the requirement for "permanent display" was 
replaced with a requirement that idenitification of 



automatic transmission shift lever positions be dis- 
played in view of the driver whenever either of the fol- 
lowing conditions exist: (a) the ignition is in a position 
in which the transmission can be shifted, or (b) the 
transmission is not in park. The purpose of the amend- 
ment was to facilitate the use of electronic displays, 
while ensuring that the information in question is dis- 
played at all times when it may be needed for safety. 
In order to take advantage of the increased flexibility 
offered by the amendment, it is generally necessary 
for a vehicle to have both a park position and a 
transmission shift interlock system, i.e., a system which 
requires the shift lever to be in park before the igni- 
tion key can be removed and which prevents the shift 
lever from being moved from park after the key is 
removed. 

NHTSA recognized a concern expressed by several 
commenters, including General Motors (GM), Ford, 
Navistar International, and the Motor Vehicle 
Manufacturers Association, that the proposed require- 
ments would not facilitate the use of electronic tech- 
nology in medium and heavy duty trucks, since those 
vehicles do not have a shift lever park position. The 
agency noted that the requirements recommended by 
those commenters were significantly different than 
those proposed in the NPRM and indicated that it 
would address that issue, as well as other issues related 
to Standard No. 102's display requirements, in a 
separate rulemaking. 

On January 12, 1990, NHTSA published in the Fed- 
eral Register (55 F.R. 1226) an NPRM addressing those 
issues. 

First, for automatic transmission vehicles without 
a park position, the agency proposed to replace the 
permanent display requirement with one that would 
require display of gear position information only when 
the key is not in the "off" or "accessory" position. 
Under the proposal, such display would also not be 
required when the ignition switch is in a position that 
is used only to start the vehicle. NHTSA tentatively 



PART 571; S102-PRE 7 



concluded that the proposed amendment would main- 
tain the safety aspects of the existing requirement 
while facilitating the use of electronic technology. 

Second, for all automatic transmission vehicles, the 
agency proposed to require that full gear position in- 
formation, i.e., identification of shift lever positions, 
including the position of the gears in relation to each 
other and the gear position selected, be provided in a 
single location. NHTSA tentatively concluded that the 
standard's purpose of reducing the likelihood of shift- 
ing errors is best met if all of the required information 
is available in one location. 

Third, the agency responded to a suggestion by 
Volkswagen that the agency amend Standard No. 102 
to provide greater flexibility for manual transmission 
pattern displays. That standard requires identification 
of the shift lever pattern of manual transmissions, 
except three forward speed manual transmissions 
having the standard "H" pattern, to be permanently 
displayed in view of the driver. Volkswagen recom- 
mended that electronic display technology be permit- 
ted as a sole indication of the manual transmission shift 
pattern. NHTSA indicated that it did not believe that 
the suggested amendment would be appropriate, given 
the safety purpose served by the requirement and the 
lack of need to change the requirement in order to 
facilitate the use of electronic displays. 

NHTSA received five comments on the January 
1990 NPRM. Four of the commenters addressed the 
agency's proposal to amend Standard No. 102's 
requirement for permanent display of gear position 
information for vehicles with automatic transmissions 
not having gear shift lever park positions. GM, Ford, 
and Chrysler supported the proposed amendment. 
Those commenters agreed that the proposed amend- 
ment would preserve the safety intent of the current 
requirement while improving design flexibility. A 
private individual, Mr. Robert Schlegel, commented 
that, in addition to not requiring display of gear posi- 
tion information in the "off" and "accessory" posi- 
tions, the amendment should also not require display 
of that information in the "lock" position. That com- 
menter stated that, for some designs, the "lock" posi- 
tion may be different from the "off" position. 

With respect to Mr. Schlegel's comment, NHTSA 
notes that the ignition designs of medium and heavy 
duty trucks, the vehicles affected by the proposal, typi- 
cally include only three positions: "off," "on," and 
"accessory." In the event that a manufacturer provided 
a "lock" position for these vehicles, however, as is often 
done for light vehicles, the agency agrees that display 
of gear position information should not be required for 
the "lock" position. The "lock" position is, in essence, 
a second "off" position. Moreover, it is the ignition 
switch position which is intended to be used when a ve- 
hicle is not being driven, and the vehicle's battery 



would be drained if electronic display of gear position 
information were provided in the "lock" position. 

NHTSA has decided to issue an amendment along 
the lines of the proposal, while taking account of the i 
possible design cited by Mr. Schlegel. Under the ' 
amendment being adopted, full gear position informa- 
tion must be displayed in all ignition switch positions 
in which the engine is capable of operation, with the 
exception of an ignition switch position that is used only 
to start the vehicle. 

Three commenters addressed the agency's pro- 
posal to require, for all automatic transmission vehicles, 
that full gear position information be provided in a 
single location. GM and Ford supported the proposal. 
GM noted that it has made this a common practice and 
believes this helps the driver obtain gear position 
information in a timely manner. 

Chrysler disagreed with the proposal to require full 
gear position information to be provided in one loca- 
tion. 'That company stated that the automotive industry 
is continuously seeking new ways to provide product 
innovation and distinction to gain a competitive edge 
in the market place, and it sees no reason to limit 
innovation in the area of gear position displays so long 
as the standard's purpose of reducing shifting errors 
is not jeopardized. Chrysler stated that it took excep- 
tion with the agency's position that the need to check 
more than one location for fiill gear position informa- 
tion would unnecessarily increase the potential for * 
driver hesitation and confusion and lead to greater v 
likelihood of shifting errors. It noted that the process 
of shifting gears while driving necessitates some diver- 
sion of the driver's attention, particularly if the full 
gear information is located on a floor console. Chrys- 
ler argued that it would be less distracting to casually 
glance at the instrument cluster area for current gear 
position than down at a floor console. That company 
also argued that the need to direct full attention to the 
task of selecting a gear position is usually done before 
the vehicle is set in motion. 

After considering the comments, NHTSA has 
decided to adopt the proposed amendment to require full 
gear position information, i.e., identification of shift lever 
positions, including the position of the gears in relation 
to each other and the gear position selected, to be pro- 
vided in a single location. The agency continues to believe 
that the standard's purpose of reducing the likelihood of 
shifting errors is best met if all of the required informa- 
tion is available in one location. K the selected gear 
position is provided in one location, e.g., "DRIVE," and 
the positions of the gears in lelation to each other, e.g., 
"P R N D L" or "P R N D 1 2" are provided in a differ- 
ent location, a driver may find it necessary to look back 
and forth between the two locations in changing gear 
positions. The agency believes that this would increase/ 
the potential for driver hesitation and confusion and leadv 
tx) greater likelihood of shifting errors. 



PART 571: S102-PRE 8 



NHTSA disagrees with Chrysler's suggestion that 
this requirement will inappropriately limit innovation 
in the area of gear position displays. For the reasons 
discussed above, the agency believes that the require- 
ment meets a safety need. Moreover, the requirement 
is not design restrictive. If Chrysler wishes to provide 
a display of current gear position information on the 
instrument panel, it is free to do so. Under the amend- 
ment, it can either provide full gear position informa- 
tion at that location, e.g., include a "P R N D L" label 
adjacent to the display of current gear position, or it 
can provide a display of current gear position informa- 
tion only on the instrument panel and include a display 
of full gear position information elsewhere, e.g., on the 
floor console. 

One commenter, Chrysler, addressed the agency's 
response to a suggestion by Volkswagen that Standard 
No. 102 be amended to provide greater flexibility for 
manual transmission pattern displays. As indicated 
above, that standard requires permanent display of 
identification of the shift lever pattern of manual 
transmissions, except three forward speed manual 
transmissions having the standard "H" pattern. Volks- 
wagen recommended that electronic display technology 
be permitted as a sole indication of the manual trans- 
mission shift pattern. NHTSA indicated that it did not 
believe that the suggested amendment would be ap- 
propriate, given the safety purpose served by the 
requirement and the lack of need to change the require- 
ment in order to facilitate the use of electronic displays. 

Chrysler argued that there is little difference 
between permitting electronic display of gear position 
information for automatic transmission vehicles 
without a "Park" position and allowing electronic 
display as the sole indication of gear shift pattern for 
manual transmission vehicles. It also argued that it 
does not believe that it is essential that the driver 
memorize the manual transmission shift pattern prior 
to the time the vehicle is started. 

While NHTSA has considered Chrysler's comment, 
it reaffirms its view that the suggested amendment 
would not be appropriate. First, while the language of 
this requirement may appear to be similar to a require- 
ment for permanent display of automatic transmission 
gear position information, the substance is quite dif- 
ferent. While it is necepsary to use a position indicator 
to show the shift lever positions of an automatic trans- 
mission, a simple label may be used to show the shift 
pattern of a manual transmission. The use of electronic 
technology is not relevant to these provisions, since 
they require only a simple label rather than a position 
indicator. Moreover, manufacturers desiring to supple- 
ment the required label with an electronic display are 
free to do so. Even if a manufacturer provides an elec- 
tronic display for manual transmissions, the need to 
also provide a simple label depicting manual transmis- 
sion shift pattern is not burdensome. 



Second, such a label serves a safety purpose. In 
order to drive a manual transmission car, a driver 
should memorize the manual transmission pattern. If 
the manual transmission shift pattern is displayed pri- 
or to the time the vehicle is started, there is a greater 
opportunity for the driver to memorize the pattern. 
Chrysler argued that it is not essential that the driver 
memorize the manual transmission shift pattern prior 
to the time the vehicle is started, any more than the 
driver of an automatic transmission vehicle with elec- 
tronic display of full gear information has to memorize 
the PRNDL information. The agency believes it is 
obvious, however, that there is a greater need for a 
driver to memorize a manual transmission shift pattern 
than an automatic transmission PRNDL pattern. 
Drivers must continuously shift manual transmissions 
as part of ordinary driving, including times when the 
vehicle is in motion. By contrast, automatic transmis- 
sions are only occasionally shifted while the vehicle is 
in motion. NHTSA continues to believe that the re- 
quirement for permanent display of manual trans- 
mission shift pattern provides a greater opportunity 
for the driver to memorize the pattern. 

One commenter. Stone Bennett Corporation, asked 
whether the proposed requirements for automatic 
transmission vehicles without a gear shift lever park 
position would be met by certain designs for shift con- 
trol consoles. In addition to including a mechanism for 
shifting the transmission (push buttons or toggle 
levers), the consoles incorporate a display which indi- 
cates the particular gear position which has been 
selected, e.g., "R" for reverse. No other gear positions 
are shown. In at least some of the designs, the display 
is an electronic one. Stone Bennett asked about the 
"acceptability" of providing a label indicating the gear 
position sequence on the body of the shift control 
console, e.g., "1 2 D N R." Drawings provided by the 
commenter indicate that the label would be provided 
directly adjacent to the gear position display. 

NHTSA notes that, as indicated above, the require- 
ments adopted today can be met by an electronic dis- 
play of current gear position with an adjacent label 
indicating the gear position sequence. The electronic 
display and adjacent label would, of course, have to be 
in the view of the driver, and the electronic display 
would have to be activated whenever the ignition is in 
a position in which the engine is capable of operation 
(with the exception of an ignition position that is used 
only to start the vehicle). 

Since the amendment to Standard No. 102's re- 
quirement for permanent display of gear position in- 
formation for automatic transmission vehicles without 
a gear shift lever park position imposes no new require- 
ments but instead increases manufacturer flexibility by 
relieving a restriction, the agency finds good cause for 
adopting an effective date of 30 days after publication 
of the final rule. 



PART 571; S102-PRE 9 



As discussed in the NPRM, NHTSA believes that 
all automatic transmission vehicles currently meet the 
requirement that full gear position information be dis- 
played in a single location. For this amendment, the 
agency is adopting an effective date of 180 days after 
publication of the final rule. 

1. S3.1.4.2 of § 571.102 is revised to read as 
follows: 

S3. 1.4.2 Except as specified in S3.1.4.3, if the 
transmission shift lever sequence does not include a 
park position, identification of shift lever positions, 
including the positions in relation to each other and the 
position selected, shall be displayed in view of the 
driver whenever the ignition is in a position in which 
the engine is capable of operation. 



S3. 1.4.4 is added to § 571.102 to read as follows: 
S3. 1.4.4 Effective April 25, 1991, all of the informa- 
tion required to be displayed by S3. 1.4.1 or S3. 1.4.2 
shall be displayed in view of the driver in a single 
location. At the option of the manufacturer, redimdant 
displays providing some or all of the information may 
be provided. 

Issued on: March 20, 1991 



Jerry Ralph Curry 
Administrator 

56 F.R. 12469 
March 26, 1991 



PART 571; S102-PRE 10 



MOTOR VEHICLE SAFETY STANDARD NO. 102 

Transmission Shift Lever Sequence, Starter Interlocit, and Transmission Bralcing Effect- 
Passenger Cars, IVIultipurpose Passenger Vehicles, Truclcs, and Buses 



51. Purpose and scope. This standard spec- 
ifies the requirements for the transmission shift 
lever sequence, a starter interlock, and for a 
braking effect of automatic transmissions, to re- 
duce the likelihood of shifting errors, starter 
engagement with vehicle in drive position, and to 
provide supplemental braking at speeds below 25 
miles per hour. 

52. Application. This standard applies to pas- 
senger cars, multipurpose passenger vehicles, 
trucks, and buses. 

53. Requirements. 

S3.1 Automatic transmissions. 

53.1.1 Location of transmission shift lever posi- 
tions on passenger cars. A neutral position shall 
be located between forward drive and reverse 
drive positions. If a steering-column-mounted 
transmission shift lever is used, movement from 
neutral position to forward drive position shall be 
clockwise. If the transmission shift lever sequence 
includes a park position, it shall be located at the 
end, adjacent to the reverse drive position. 

53.1.2 Transmission braking effect. In vehicles 
having more than one forward transmission gear 
ratio, one forward drive position shall provide 
a greater degree of engine braking than the 
highest speed transmission ratio at vehicle speeds 
below 25 miles per hour. 

53.1.3 Starter interlock. The engine starter 
shall be inoperative when the transmission shift 
lever is in a forward or reverse drive position. 

S3.1.4.1 Except as specified in S3. 1.4. 3, if the 
transmission shift lever sequence includes a park 
position, identification of shift lever positions, in- 
cluding the positions in relation to each other and 



the position selected, shall be displayed in view of 
the driver whenever any of the following condi- 
tions exist: 

(a) The ignition is in a position where the 
transmission can be shifted. 

(b) The transmission is not in park. 

53.1.4.2 [Except as specified in S3. 1.4.3, if the 
transmission shift lever sequence does not include 
a park position, identification of shift lever posi- 
tions, including the positions in relation to each 
other and the position selected, shall be displayed 
in view of the driver whenever the ignition is in a 
position in which the engine is capable of opera- 
tion. (56 F.R. 12469— March 26, 1991. Effective: 
April 25, 1991)1 

53.1 .4.3 Such information need not be displayed 
when the ignition is in a position that is used only 
to start the vehicle. 

IS3.1.4.4 Effective April 25, 1991, all of the in- 
formation required to be displayed by S3. 1.4.1 or 
S3. 1.4.2 shall be displayed in view of the driver in a 
single location. At the option of the manufacturer, 
redundant displays providing some or all of the in- 
formation may be provided. (56 F.R. 12469— March 
26, 1991. Effective: April 25, 1991).! 

S3.2 {Manual transmissions. 

Identification of the shift lever pattern of manual 
transmissions, except three forward speed manual 
transmissions having the standard "H" pattern, 
shall be displayed in view of the driver at all times 
when a driver is present in the driver's seating 
position. 



February 3, 1967 
32 F.R. 2410 
February 3, 1967 



(Rev. 3/26/91) 



PART 571; S 102-1-2 



Effactiv*: January 1, 1969 



PREAMBLE TO AMENDMENT TO MOTOR VEHICLE SAFETY STANDARD NO. 103 

Windshield Defrosting and Defogging Systems — Passenger Cars, 
Multipurpose Passenger Vehicles, Trucks and Buses 

(Docket Nos. 9, 1-12) 



Motor Vehicle Safety Standard No. 103 (32 
F.R. 2410) requires .that each passenger car and 
multipurpose passenger vehicle manufactured for 
sale in the C!ontinental United States be provided 
with a windshield defrosting and defogging sys- 
tem. A proposal to amend section 371.21 of 
Part 371, Federal Motor Vehicle Safety Stand- 
ards, by amending Standard No. 103, was pub- 
lished in the Federal Register on December 28, 
1967 (32 F.R. 20867). 

Interested persons have been afforded an op- 
portunity to participate in the making of the 
amendment. Their comments, as well as other 
available information, have been carefully con- 
sidered. 

The purpose of the amendment is to increase 
driver visibility, and thereby enhance safe ve- 
hicle performance, by (1) adding test conditions 
and performance requirements for passenger car 
defrosting and defogging systems; and (2) 
broadening the standard's application to cover 
trucks and buses, which were not subject to the 
initial standard. In addition, the standard was 
modified to improve its clarity. 

Paragraph S4.3 in the notice of proposed rule- 
making required testing of passenger car wind- 
shield defrosting and defogging systems in ac- 
cordance with the test conditions specified in 
paragraph 4 of SAE Recommended Practice 
J902, August 1964. Several comments asked that 
this requirement be modified to permit optional 
use of the test conditions set out in paragraph 4 
of SAE Recommended Practice J902a, March 
1967, a revised version of the Recommended Prac- 
tice. The Administrator has determined that 
there are only minor differences between the test 
equipment, instrumentation, conditions and pro- 
cedures in paragraphs 4.1 through 4.4.7 of these 



two versions, and that these minor differences do 
not affect the level of safety attained with the 
use of either one. Accordingly, S4.3 of the notice 
has been changed to permit the use of the demon- 
stration procedures described in paragraphs 4.1 
through 4.4.7 of either SAE Recommended Prac- 
tice J902 or SAE Recommended Practice J902a. 

Another feature of paragraph S4.3 which 
evoked comments was its provision for use of 
the test procedures in section 4 of Recommended 
Practice J902 to the extent they are "applicable 
to" the particular system being tested. Any pos- 
sible ambiguity that might appear upon super- 
ficial examination of the quoted words disappears 
when this requirement is read in conjunction with 
the operative provisions of section 4 of the SAE 
Recommended Practices. Section 4 makes refer- 
ence to certain components that are not incor- 
porated in every passenger car (e.g. defroster 
blowers) . The use of the section 4 test procedures 
is restricted to those procedures "applicable to" 
the particular passenger car system being tested 
to make it clear that procedures which, by their 
terms, apply to components that are not a part 
of the car being tested need not be complied with. 

Three comments asked that paragraph S4.2 
of the standard be changed to permit optional 
use of the defrosted area and defrosting time 
requirements prescribed in section 3 of SAE 
Recommended Practice J902a in lieu of those set 
forth in section 3 of Reconmiended Practice 
J902. In the notice of proposed nilemaking, 
paragraph S4.2 incorporated, with minor modi- 
fications, the defrosted area and defrosting time 
requirements of Recommended Practice J902. 
Comparison of the two versions of the SAE 
Recommended Practice reveals that there are 
great differences between the areas and times 



PART 571; S 103— PRE 1 



IffatHva: January 1, 1969 



prescribed by J902 and those prescribed by 
J902a. The requests for a change in paragraph 
S4.2 acknowledged that compliance with one pro- 
cedure is not necessarily more difficult than com- 
pliance with the other. The submissions did not 
indicate that adherence to the J902 requirements 
would impose any significant burden or would 
be impracticable in any sense. In view of the 
absence of sufficient substantiation to justify 
changing the standard, paragraph S4.2 has not 
been modified to allow alternative defrosted area 
and defrosting time requirements. 

One comment requested that the standard be 
changed to allow 5 minutes more to meet the 
defrosted area requirements of the critical or "C" 
area. It was said that reasonable performance 
tolerances should be taken into account, and that, 
therefore, the requirement of paragraph 3.1 of 
SAE Recommended Practice J902, as adopted 
in modified form in paragraph S4.2 of the stand- 
ard, that the "C" area must be 80 percent de- 
frosted after 20 minutes of operation should be 
changed to allow manufacturers 25 minutes to 
attain the 80 percent defrosted goal. Such a 
modification would permit a significant reduc- 
tion of the defrosting performance of defrosting 
and defogging systems and this, in turn, would 
be contrary to the interest of safety. While it 
is true that variations in such things as the per- 
formance of the thermostat and the outlet nozzle 
will affect the system's capability to defrost a 
given windshield area within a stated time, there 



is no apparent reason why it is impracticable to 
design and construct the system so that, at a 
minimum performance level, it will comply with 
the requirements of paragraph S4.2. For these 
reasons, the Administrator has rejected this re- 
quest for modification of the standard. 

Many comments submitted suggestions that 
went beyond the scope of the notice. For ex- 
ample, submissions that discussed the problems 
of establishing performance requirements for de- 
frosting and defogging systems on multipur- 
pose passenger vehicles, trucks, and buses were 
received. These, and other comments of this 
nature, will be considered in connection with 
future rulemaking action. 

In consideration of the foregoing, § 371.21 of 
Part 371, Federal Motor Vehicle Safety Stand- 
ards, is amended, effective January 1, 1969, by 
amending Motor Vehicle Safety Standard No. 
103 ... . 

This amendment is made under the authority 
of sections 103 and 119 of the National Traffic 
and Motor Vehicle Safety Act of 1966 (15 U.S.C. 
1392, 1407) and the delegation of authority of 
April 24, 1968. 

Issued in Washington, D. C. on April 24, 1968. 

Lowell K. Bridwell, 

Federal Highway Administrator. 

33 F.R. 6468 
April 27, 1968 



PART 571; S 103— PRE 2 



EfFacllv*: September 1, 1975 



PREAMBLE TO AMENDMENT TO MOTOR VEHICLE SAFETY STANDARD NO. 103 

Windshield Defrosting and Defogging Systems 

(Docket No. 73-6; Notice 2) 



The purpose of this notice is to amend Motor 
Vehicle Safety Standard No. 103, Windshield 
Defrosting and Defogging Systems, to revise the 
wind test condition. 

On March 20, 1973, the National Highway 
Traffic Safety Administration published a notice 
(38 F.R. 7339) proposing a change in the stand- 
ard's wind velocity test condition which would 
clarify the NHTSA's intent that the perform- 
ance requirements be met at all levels within the 
specified wind speed range. The present provi- 
sion specifying that "the wind velocity may not 
exceed 5 mph" may be interpreted by manufac- 
turers as requiring compliance at only one point 
within the range. Such an interpretation could 
result in enforcement problems if the NHTSA 
discovered a failure to comply when testing a 
vehicle at one point within the range while the 
manufacturer had attained compliance during 
testing at another point within the specified wind 
speed range. Perpetuation of this type of en- 
forcement situation might retard the develop- 
ment of complying vehicle systems and under- 
mine the level of performance the NHTSA 
intends to accomplish. Therefore, the NHTSA 
proposed in its March 20, 1973, notice that the 
standard specify that the wind velocity test con- 
dition be at any level from to 2 mph. Reading 
this requirement together with the interpretive 
provisions of § 571.4, the vehicle would be re- 
quired to be capable of complying with the 
standard when the wind velocity is at any speed 
within that range. This would prevent any dis- 
crepancy between the manufacturers' and the 
NHTSA's conception of what the standard 
actually requires. 



Several comments submitted in response to the 
proposal to revise the wind speed test condition 
asserted that wind speeds cannot be accurately 
measured below 2 mph, and therefore the require- 
ment should remain unchanged. This objection 
lacks merit, since the standard only requires that 
a vehicle be capable of complying with the stand- 
ard at wind speeds from to 2 mph. A manu- 
facturer may generally conduct his testing at 
higher wind speeds to determine compliance, 
since the greater the wind speed, the more diffi- 
cult it is to defrost the windshield within the 
specified time span. 

The March 20, 1973, notice also proposed that 
the test chamber temperature sensor be located 
in a position not substantially affected by the 
heat from the engine. Comments from Ford and 
General Motors, submitted in response to this 
aspect of the proposal, objected to the proposed 
temperature location as unobjective and ambig- 
uous and suggested establishment of a more 
specific location. The NHTSA is in tentative 
agreement with commenters' suggestion and is 
proposing in a separate notice issued today an 
exact location for the temperature sensor. 

In consideration of the foregoing, in S4.3 of 
49 CFR § 571.103, Motor Vehicle Safety Stand- 
ard No. 103, paragraph (g) is amended. . . . 

Effective date: September 1, 1975. 

(Sees. 103, 119, Pub. L. 89-563, 80 Stat. 718, 
15 U.S.C. 1392, 1407; delegation of authority 
at 49 CFR 1.51.) 

Issued on March 17, 1975. 

James B. Gregory 
Administrator 

40 F.R. 12991 
March 24, 1975 



PART 571; S 103— PRE 3-4 



Effective: September 1, 1975 



PREAMBLE TO AMENDMENT TO MOTOR VEHICLE SAFETY STANDARD NO. 103 

Windshield Defrosting and Defogging Systems 
(Docket No. 73-6; Notice 4) 



The purpose of this notice is to amend Motor 
Vehicle Safety Standard No. 103, Windshield 
Defrosting and Defogging Systems, 49 CFR 
571.103, to specify a relocation of the test cham- 
ber temperature and wind velocity sensors. 

On March 24, 1975, the National Highway 
Traffic Safety Administration published a notice 
(40 F.R. 13002) proposing a change in the loca- 
tion of the test chamber temperature and wind 
velocity sensors to a position where they would 
not be affected by air released from vehicle en- 
gines during testing. A petition from Jaguar 
Cars Division of British Leyland UK Limited, 
describing compliance problems for vehicles that 
direct engine heat at the windshield as part of 
the defrosting process, prompted the rulemaking 
action. 

It was proposed that the temperature and 
wind sensors be positioned at the forwardmost 
point of the vehicle or 36 inches from the base 
of the windshield, whichever is farther forward, 
at a level halfway between top and bottom of the 
windshield. At this location, the NHTSA con- 
cluded that the temperature measurement would 
not be affected by expelled engine heat and the 
wind measurement would not be affected by air 
released from hood ducts. 

Comments to the proposal were received from 
Chrysler, Jaguar, and General Motors. Both 
Chrysler and General Motors supported adop- 
tion of the amendment. 



Jaguar took issue with the proposed thermo- 
couple location and asked that the sensors be 
placed 3 feet forward of the vehicle. The 
NHTSA denies this request, having found that 
the proposed thermocouple position provides for 
reliable and objective temperature and wind ve- 
locity measurements. Location of the sensors at 
the position suggested by Jaguar is therefore 
unnecessary and would tend to penalize those 
manufacturers using short cold chambers for 
compliance testing. The purpose of the amend- 
ment is to relocate the temperature and wind 
sensors to locations where they will not be af- 
fected by air released from vehicle engines. The 
agency concludes that the proposed location ac- 
complishes this goal and should therefore be 
adopted. 

In consideration of the foregoing. Standard 
No. 103 (49 CFR 571.103) is amended by adding 
in S4.3 a new paragraph (h). . . . 

Effective date: September 1, 1975. 

(Sees. 103, 119, Pub. L. 89-563, 80 Stat. 718, 
15 U.S.C. 1392, 1407; delegation of authority at 
49 CFR 1.51.) 

Issued on July 28, 1975. 

James B. Gregory 
Administrator 

40 F.R. 32336 
August 1, 1975 



PART 571; S 103— PRE 5-6 



PREAMBLE TO AN AMENDMENT TO 
FEDERAL MOTOR VEHICLE SAFETY STANDARD NO. 103 

Windshield Defoggers 
[Docltet No. 83-10; Notice 2] 



ACTION: Final Rule 

SUMMARY: This notice amends Standard No. 103, 
Windshield Defrosting and Befogging Systems, to require 
that passenger cars, multipurpose passenger vehicles, 
trucks, and buses manufactured for sale in the noncon- 
tinental United States be equipped with defogging systems. 
The noncontinental United States includes such areas as 
Hawaii, Puerto Rico, the Virgin Islands, Guam, and 
American Samoa. The agency believes that adoption of 
this amendment will eliminate the safety hazard caused 
by fogging of vehicle windshields in vehicles without 
defogging systems in the damp weather prevalent in these 
geographic areas and having to manually wipe those wind- 
shields in order to see properly. 

EFFECTIVE DATE: September 1, 1987. 

SUPPLEMENTARY INFORMATION: Standard No. 
103, Windshield Defrosting and Defogging Systems, cur- 
rently applies to passenger cars, multipurpose passenger 
vehicles, trucks, and buses which are manufactured for 
sale in the continental United States (including Alaska). 
The standard requires manufacturers to install systems 
which perform both windshield defrosting and defogging 
functions in those vehicles. 

When the original rule was issued, the agency believed 
there was no justification for requiring defrosting equip- 
ment on vehicles manufactured for sale in the warm, 
humid regions of the noncontinental United States. There- 
fore, these vehicles are not required to be equipped with 
the combined windshield defrosting and defogging 
systems required under Standard No. 103. The noncon- 
tinental United States includes such areas as Hawaii, 
Puerto Rico, the Virgin Islands, Guam and American 
Samoa. Standard No. 103 is the only Federal motor vehi- 
cle safety standard which exempts vehicles manufactured 
for sale in the noncontinental United States. 



Domestic manufacturers install combined defrosting and 
defogging systems on all passenger cars, regardless of 
where they are sold. However, several foreign manufac- 
turers do not include any type of defrosting or defogging 
equipment on many of their vehicles sold in the noncon- 
tinental United States. For the reasons set forth below, 
this rule amends the standard to require all manufacturers 
to install, at their option, either a defrosting and defog- 
ging system or a defogging system, in all vehicles 
manufactured for sale in the noncontinental United States. 



Safety Problem 

On July 14, 1983, (48 FR 32200), NHTSA issued a 
notice of proposed rulemaking which responded to a peti- 
tion for rulemaking filed by Sunrise Motors, Inc. The peti- 
tioner claimed that windshields in the Virgin Islands fog 
up very badly in damp weather, creating a serious safety 
hazard in vehicles which do not have defogging systems. 
The petitioner therefore requested that manufacturers be 
required to install defogging systems in passenger cars 
sold in the Virgin Islands. 

The agency reviewed the climatic conditions of the 
Virgin Islands as well as in the rest of the noncontinental 
United States and determined that the petitioner's claim 
that these conditions are conducive to the occurrence of 
windshield fogging on a regular basis is accurate. The fog- 
ging occurs when a cool windshield comes into contact 
with warm, moist air and the water vapor in the air con- 
denses in the form of a liquid on the windshield. AH the 
geographic areas in question are characterized by high 
temperatures and high humidity. Windshield fogging is 
especially likely to occur in the morning hours. 

Under these conditions windshield fogging reduces 
visibility, substantially. Thus, driving a vehicle without 
defogging equipment that clears the windshield 



FART 571; SI 03— PRE 7 



automatically, poses a safety hazard. In addition, in the 
absence of defogging equipment, drivers try to manually 
wipe the windshield clean while driving — a process which 
itself is distracting and creates a safety hazard. The agency 
therefore believes that a vehicle without defogging equip- 
ment creates an unreasonable safety risk. This is true not 
only for passenger cars, the specific subject of the peti- 
tion for rulemaking, but also for multipurpose passenger 
vehicles, trucks, and buses. Thus, the notice proposed to 
require windshield defogging systems in passenger cars, 
multipurpose passenger vehicles, trucks, and buses. 

Automobile Importers of America, Inc., supplied in- 
formation concerning the sales of passenger cars by four 
foreign manufacturers in the noncontinental United States 
with and without defrost and defogging equipment. Ac- 
cording to these data, more than 76,000 automobiles were 
shipped to the noncontinental United States in 1980 by 
these companies. Approximately 40,000 of these cars, 
representing 52 percent of the total, were not equipped 
with defrosting and defogging equipment. The total vehi- 
cle population without defogging equipment is likely to 
be larger when other passenger car imports, multipurpose 
passenger vehicles, trucks, and buses are included; 
however, the agency does not have specific data on the 
total vehicle population. Therefore, a significant number 
of foreign-manufactured vehicles in these areas are being 
operated without a defogging system to improve visibil- 
ity. This situation obviously increases the risk of motor 
vehicle accidents, injuries, or deaths. 

Alternative Requirements 

Three comments were received on the notice, two from 
vehicle manufacturers. None of the commenters on the 
notice of proposed rulemaking opposed this amendment 
to Standard No. 103. 

Amending the standard to require vehicles manufactured 
for sale in the noncontinental United States to have defog- 
ging systems is not simply a matter of extending the ap- 
plicability of the standard to the additional geographic 
areas. Standard No. 103 requires vehicles built for sale 
in the continental United States to have a system which 
defrosts as well as defogs. The standard does not currently 
specify separate performance requirements for defogging. 
Instead, for passenger cars, the defrosting requirements 
of the standard serve the double purpose of ensuring ade- 
quate defrosting and defogging performance. This is pxjssi- 
ble because the amount of heat necessary for adequate 
defrosting, i.e. , for melting ice that forms on a windshield, 
also provides adequate defogging performance. For 
multipurpose passenger vehicles, trucks, and buses, the 
standard simply requires a windshield defrosting and 



defogging system and does not specify any performance 
requirements. 

The agency does not consider it appropriate to extend 
the defrosting requirements of Standard No. 103 to 
vehicles manufactured for sale in Hawaii, Puerto Rico, 
the Virgin Islands, Guam, and American Samoa. Since 
those areas have warm climates, there is no safety need 
for vehicles to have a defrosting (as opposed to defog- 
ging) system. 

This rule gives manufacturers the option of complying 
with the defogging requirement in alternative ways. Com- 
bination defrosting and defogging equipment can be in- 
stalled in the vehicles. As noted earlier, domestic 
manufacturers currently do so in passenger cars. The 
agency's rule also permits manufacturers to design a 
system with only defogging capability for installation in 
vehicles for sale in the noncontinental United States. 

There are two major ways to provide windshield defog- 
ging capability, by applying heat to the windshield or by 
dehumidifying the air inside a vehicle. The first method 
is the same as that used for defrosting, although less heat 
may be necessary for defogging. Therefore, a manufac- 
turer may be able to design a defog-only system using 
heat application which is less expensive than a standard 
defrosting and defogging system. The second method, de- 
humidifying the air inside a vehicle, is considerably more 
expensive than the first method and therefore unlikely to 
be used for defogging only purposes. Since air condi- 
tioners dehumidify the air inside a vehicle in addition to 
cooling it, all vehicles equipped with air conditioners have 
defogging capabilify, whether or not they have a com- 
bined defrosting and defogging system. Thus, vehicles 
with air conditioners would not need an additional defog- 
ging system to meet this rule's amendments. 

The agency is not requiring a defogging system for side 
or rear windows of passenger cars, as requested by the 
petitioner. The primary problem created by fogging in- 
volves the windshield. For this reason, there is currently 
no requirement for side or rear window defogging equip- 
ment in vehicles manufactured for sale in the continental 
United States. 

Toyota Motor Corporation suggested that an alternative 
defogging method be allowed which applies outside am- 
bient air directly to the windshield using a boost ventilator 
system. The agency believes that the Toyota system would 
not be able to defog a windshield as quickly as the other 
alternatives, particularly when very high humidity con- 
ditions exist. Moreover, the agency has no data which 
show that a boost ventilator defogger system would pro- 
vide equivalent defogging capability in multipurpose 
passenger vehicles, trucks, or buses. For these reasons, 
the agency will not permit the use of a boost ventilator 



PART 571; SI 03— PRE 8 



defogger system for defog-only purposes under this 
amendment. As stated earlier, the vehicle manufacturer 
will have the option of installing a windshield defog-only 
system which operates either by applying heat to the wind- 
shield or by dehumidifying the air inside the passenger 
compartment of the vehicles. Of course, a combined wind- 
shield defrosting and defogging system could be installed 
instead of a defog-only system. 



Defogging Performance Requirements 

Transportation Safety Consultants (TSC) stated that the 
defrosting performance requirements of the standard 
should be amended to include other vehicles as well as 
passenger cars. In addition, TSC urged the agency to set 
specific defogging performance requirements for all 
vehicles. The changes sought by TSC are beyond the 
scope of this petition. First, the agency did not propose 
to amend the defrosting requirements of Standard 103. 
Therefore, extending the current requirements for 
defrosters to other passenger vehicles is inappropriate as 
part of this rulemaking. In addition, the agency disagrees 
with TSC that a vehicle equipped with a combined 
defrosting and defogging system or an air-conditioning 
unit may not have adequate defogging capability. The 
agency also believes it is reasonable to require the installa- 
tion of defogging equipment only, on vehicles manufac- 
tured for sale in the noncontinental United States without 
specific defogging performance requirements, primarily 
because defogging equipment provides obvious and im- 
portant safety benefits by improving visibility in these 
geographic regions. 



Potential Benefits, Costs and Other Effects 

The agency has evaluated the economic and other ef- 
fects of this final rule and determined that they are neither 
major as defined by Executive Order 12291 nor signifi- 
cant as defined by the Department's Regulatory Policies 
and Procedures. 

The safety benefits of this rule are difficult to quantify, 
as they usually are for crash avoidance safety standards. 
However, the agency believes there is no rationale for 
exempting vehicles manufactured for sale in the noncon- 
tinental United States from the requirement to install 
defogging equipment. As discussed earlier, there are 
adverse safety consequences that result from not having 
a defogger. Vehicles manufactured for sale in those loca- 
tions were only exempted from the defogging require- 
ments because of an oversight. When Standard 103 was 
first proposed its provisions would have applied to the 



noncontinental United States. However, since the Stan- 
dard also included defrosting (i.e., deicing) requirements, 
it was recognized that these would be inappropriate for 
the noncontinental United States. Because of statutory 
deadlines for issuance of initial safety standards, the 
agency did not have time to re-propose only the defog- 
ging requirements and thus exempted the noncontinental 
United States from all the requirements of Standard 103. 
This rule corrects the oversight. 

Although the agency cannot quantify the possible reduc- 
tion in accidents, deaths, and injuries, requiring a defog- 
ger will improve safety by providing increased visibility 
through a vehicle's windshield and by eliminating the need 
to manually wipe the windshield while driving. The 
agency's final regulatory evaluation analyzes the poten- 
tial effects on safety of this action. 

The final regulatory evaluation also contains cost in- 
formation prepared by the agency. NHTSA conducted an 
independent analysis of a complete Standard No. 103 
defrosting and defogging system based on tear-down 
analyses of a Chevrolet Citation and a Plymouth Reliant. 
These costs are in the $60 to $68 per vehicle range which 
•equates with the lower end of cost figures supplied by 
foreign manufacturers. As noted above, defog-only 
systems would cost less, if manufacturers choose to design 
that type of system, although the exact lower amount is 
not known. Since domestically produced vehicles already 
come equipped with defoggers, this rulemaking does not 
add any cost to manufacturers of those vehicles. The 
estimated cost of this rule would be $2.4 million to $2.7 
million for passenger cars sold by foreign manufacturers 
in these locales. 

The agency believes that the effective date of this rule, 
September 1, 1987, is reasonable, because this leadUme 
may be necessary for manufacturers to design defog-only 
systems if they choose this option for vehicles manufac- 
tured for sale in the noncontinental United States. 

In consideration of the foregoing, §571.103, Windshield 
Defrosting and Defogging Systems, is amended as follows: 

1 . The authority citation for Part 571 continues to read 
as follows: 

15 U.S. C. 1392, 1401, 1403, 1407, delegations of 
authority at 49 CFR 1.50. 

2. Paragraph S2 is revised to read as follows: 

S2. Application. This standard applies to passenger 
cars, multipurpose passenger vehicles, trucks, and buses. 

3. Paragraph S4 is revised to read as follows: 

S4. Requirements, (a) Except as provided in 
paragraph (b) of this section, each passenger car shall meet 
the requirements specified in S4.1, S4.2, and S4.3, and 
each multipurpose passenger vehicle, truck, and bus shall 
meet the requirements specified in S4.1. 



PART 571; S103— PRE 9 



(b) Each passenger car, multipurpose passenger vehi- Issued on November 21, 1985 

cle, truck, and bus manufactured for sale in tKe noncon- 
tinental United States may, at the option of the manufac- 
turer, have a windshield defogging system which operates Diane K. Steed 
either by applying heat to the windshield or by dehumidi- Administrator 
lying the air inside the passenger compartment of the vehi- 
cle, in lieu of meeting the requirements specified by 50 FR 48772 
paragraph (a) of this section. November 27, 1985 



PART 571; S 103— PRE 10 



MOTOR VEHICLE SAFETY STANDARD NO. 103 



Windshield Defrosting and Defogging Systems— Passenger Cars, Multipurpose 
Passenger Vehicles, Trucks, and Buses 



51. Scope. This standard specifies re- 
quirements for windshield defrosting and defogging 
systems. 

52. Application. [This standard applies to 
passenger cars, multipurpose passenger vehicles, 
trucks, and buses. (50 F. R. 48772-November 27, 
1985. Effective: September 1, 1987)1 

53. Definitions. "Road load" means the power 
output required to move a given motor vehicle at 
curb weight plus 400 pounds on level, clean, dry, 
smooth Portland cement concrete pavement (or 
other surface with equivalent coefficient of surface 
friction) at a specified speed through still air at 68°F 
and standard barometric pressure (29.92" of Hg.) 
and includes driveline friction, rolling friction, and 
air resistance. 

54. Requirements. 

[(a) Except as provided in paragraph (b) of this 
section, each passenger car shall meet the re- 
quirements specified in S4.1, S4.2, and S4.3, and 
each multipurpose passenger vehicle, truck, and 
bus shall meet the requirements specified in S4.1. 

(b) Each passenger car, multipurpose passenger 
vehicle, truck, and bus manufactured for sale in the 
noncontinental United States may, at the option of 
the manufacturer, have a windshield defogging 
system which operates either by applying heat to 
the windshield or by dehumidifying the air inside 
the passenger compartment of the vehicle, in lieu 
of meeting the requirements specified by 
paragraph (a) of this section. (50 F. R. 
48772-November 27, 1985. Effective: September 
1, 1987)1 

S4.1 Each vehicle shall have a windshield 
defrosting and defogging system. 



54.2 Each passenger car windshield defrosting 
and defogging system shall meet the requirements 
of section 3 of SAE Recommended Practice J902, 
"Passenger Car Windshield Defrosting Systems," 
August 1964, when tested in accordance with S4.3, 
except that "the critical area" specified in 
paragraph 3.1 of SAE Recommended Practice 
J902 shall be that established as Area C in accor- 
dance with Motor Vehicle Safety Standard No. 
104, "Windshield Wiping and Washing Systems," 
and "the entire windshield" specified in paragraph 
3.3 of SAE Recommended Practice J902 shall be 
that established as Area A in accordance with 
Motor Vehicle Safety Standard No. 104. 

54.3 Demonstration procedure. The passenger 
car windshield defrosting and defogging system shall 
be tested in accordance with the portions of 
paragraphs 4.1 through 4.4.7 of SAE Recommended 
Practice J902, August 1964, or SAE Recommended 
Practice J902a, March 1967, applicable to that 
system, except that— 

(a) During the first five minutes of the test, 
the engine speed or speeds may be those which 
the manufacturer recommends as the warm-up 
procedure for cold weather starting; 

(b) During the last 35 minutes of the test 
period (or the entire test period if the five-minute 
warm-up procedure is not used), either— 

(i) The engine speed shall not exceed 1500 
rpm in neutral gear; or 

(ii) The engine speed and load shall not ex- 
ceed the speed and load at 25 mph in the 
manufacturer's recommended gear with road 
load; 

(c) A room air change of 90 times per hour is 
not required; 

(d) The windshield wipers may be used during 
the test if they are operated without manual 
assist; 



(Rev. 11/27/85) 



PART 571; S 103-1 



(e) One or two windows may be open a total of been started, at the forwardmost point of the 
one inch; vehicle or a point 36 inches from the base of the 

(f) The defroster blower may be turned on at any windshield, whichever is farther forward, at a 
time- and 1^^^' halfway between the top and bottom of the 

(g)' The wind velocity is at any level from to 2 windshield on the vehicle centerline. 
mph. 

(h) The test chamber temperature and the wind 33 F.R. 6469 

velocity shall be measured, after the engine has April 27,1968 



PART 571; S 103-2 



Eff*<«<v«: January 1, 1969 



PREAMBLE TO AMENDMENT TO MOTOR VEHICLE SAFETY STANDARD NO. 104 

Windshield Wiping and Washing Systems — Passenger Cars, Multipurpose 
Passenger Vehicles, Trucks, and Buses 

(Docket No. 7) 



Motor Vehicle Safety Standard No, 104 (32 
F.R. 2410) specifies requirements for windshield 
wiping and washing systems for passenger cars 
68 or more inches in overall width. A proposal 
to amend section 371.21 of Part 371, Federal 
Motor Vehicle Safety Standards, by amending 
Standard No. 104 was published in the Federal 
Register on December 28, 1967 (32 F.R. 20867). 

Interested persons have been afforded an oppor- 
tunity to participate in the making of the amend- 
ment. Their conmients, as well as other avail- 
able information, have been carefully considered. 

The primary purpose of the amendment is to 
broaden the application of the Initial Standard 
to cover smaller passenger cars, multipurpose pas- 
senger vehicles, trucks, and buses. The wiped- 
area performance requirements have been ex- 
tended to cars smaller than 68 inches wide, and 
tables which prescribe the minimum size of wiped 
areas have been added for such cars. The 
overall effect is that the wiper systems of various 
passenger cars must wipe areas to provide ap- 
proximately equivalent driver vision. The wiper 
frequency requirement, modified to prescribe that 
the highest and lowest frequencies must differ by 
at least 15 cycles per minute, has been extended 
to multipurpose passenger vehicles, trucks, and 
buses. A requirement for a windshield washing 
system has also been extended to smaller cars, 
multipurpose passenger vehicles, trucks, and 
buses. Other modifications to the standard were 
made in order to improve its clarity. 

The mf^rial received in response to the notice 
of proposed rulemaking evinced almost universal 
acknowledgement that broadening of the cover- 
age of the standard would improve overall driver 
visibility and thus contribute to safety on the 
highways. With a few minor exceptions, dis- 



cussed below, there was no suggestion that manu- 
facturers would have any difficulty in complying 
with the revised requirements by the January 
1, 1969, effective date. 

Some of the comments indicated some misun- 
derstanding of the reference to SAE Recom- 
mended Practice J903a, "Passenger Car Wind- 
shield Wiper Systems," May 1966, in paragraph 
S4.1.2 of the standard. Paragraph S4.1.2 is part 
of the wiped area requirement and it provides, 
among other things, for testing "in accordance 
with" SAE Recommended Practice J903a. This 
does not mean that all of section 4, "Test Meth- 
ods," of SAE Recommended Practice J903a is 
incorporated by reference into the wiped area 
requirements of the standard. The reference to 
the SAE Recommended Practice relates only to 
its procedure for testing wiper systems for com- 
pliance with wiped area requirements. Therefore, 
the ozone test, wiper system stall test, 1,500,000- 
cycle durability test, and other details of section 
4 of SAE Recommended Practice J903a are not 
included in the scope of Standard No. 104. 

Several comments asked that the standard con- 
tain a demonstration procedure for testing wind- 
shield wiper systems for compliance with the 
45-cycle-per-minute frequency requirement and 
the 15-cycle-per-minute frequency differential re- 
quirement. Apparently, these persons were con- 
cerned that the ability of systems to meet both 
requirements might be judged under abnormal 
conditions rather than under those encountered 
in normal driving. Considering these requests 
reasonable, the Administrator has provided that 
windshield wiper systems will be deemed to have 
met the frequency differential requirements of the 
standard (sections S4.1.2 and S4.1.1.3) if they 
meet those requirements when tested in accor- 



PART 571; S 104— PRE 1 



EfFMtIv*: January 1, 1969 



dance with sections 4.1.1 and 4.1.2 of SAE Rec- 
ommended Practice J903a. 

One comment requested clarification of the lo- 
cation of the plan view reference line in the 
"eyellipse." The "eyellipse" is the "95 percent 
eye range contour" specified in SAE Recom- 
mended Practice J941, "Passenger Car Driver's 
Eye Range," November 1965. The author of this 
comment pointed out that Figure 2 in Recom- 
mended Practice J903a incorrectly shows the plan 
view reference line as located through the geo- 
metric center of the 95 percent eye range con- 
tour. The drawings referred to in Recommended 
Practice J941 show the "eyellipse" centerline as 
disecting the left ellipse of the two intersecting 
ellipses in the plan view. In paragraph S3 of the 
standard, the definition of the "95 percent eye 
range contour" makes reference to SAE Recom- 
mended Practice J941, which correctly positions 
the plan view reference line in the left-hand 
ellipse of the "eyellipse." Accordingly, the Ad- 
ministrator has determined that subparagraph 
(a) of the definition of "plan view reference line" 
in paragraph S3 of the standard correctly reflects 
this position as defined, but subparagraph (b) 
of the same definition has been modified to 
clarify the location of the "eyellipse." Sub- 
paragraph (b), as revised by this amendment, 
places the plan view reference line outboard of 
the longitudinal centerline of the driver's desig- 
nated seating position, thus locating the "eyel- 
lipse" itself geometrically in the center of the 
seat. 

In the notice of proposed rulemaking, para- 
graph S4.2 required a windshield washing system 
meeting the requirements of SAE Recommended 
Practice J942, "Passenger Car Windshield 
Washer Systems," November 1965. Section 3.1 of 
that Recommended Practice sets washer system 
capability requirements by reference to the pas- 
senger car wiped area requirements of SAE Rec- 
ommended Practice J903. Several comments 
pointed this out and requested modification of 
the standard in view of the fact that the wiped 
area requirements of the standard are different 
from those of Recommended Practice J903. In 
addition, some comments sought revision of this 
particular provision on the ground that the wiped 
areas of Recommended Practice J903 were created 
for passenger cars, while the washer provisions 



of the standard apply to multipurpose passenger 
vehicles, trucks, and buses as well. In view of 
these comments, the Administrator has deleted the 
cross-reference, and S4.2 of the standard has 
been modified. The passenger car wiped-area re- 
quirement is now defined as that established 
under paragraph S4.1.2.1 of the standard; the 
wiped area for multipurpose passenger vehicles, 
trucks, and buses is now defined as the wiped 
area pattern designed by the manufacturer for 
the windshield wiping system on the exterior of 
the windshield glazing. 

One comment sought a change in the wiper 
frequency differential requirement from 16 cycles 
per minute to 10 cycles per minute, claiming that 
production tolerances did not permit exact com- 
pliance with the 15-cycle-per-minute differential 
requirement. The comment did not indicate why, 
assuming a 5-cycl6-per-minute tolerance is 
needed, the system could not be constructed to 
operate in the frequency differential range of be- 
tween 15 and 20 cycles per minute rather than a 
10-15 cycle range. The standard, like all stand- 
ards, is a minimum one, and nothing in it pro- 
hibits a higher standard of performance than the 
one specified as minimal. For these reasons, and 
because the deviation requested would, if granted, 
lower the safety performance of this segment of 
the standard, the request has been denied. 

Similarly, the Administrator has denied a re- 
quest for deletion of the requirement that wind- 
shield washing systems must, when tested, deliver 
approximately 15 cc. of fluid to the windshield 
glazing surface. The requirement is embodied 
in section 2.11 of SAE Recommended Practice 
J942, which is incorporated by reference in para- 
graph 4.2 of the standard. The amount of fluid 
placed on the windshield's exterior is a central 
performance characteristic of a washing system, 
and a decrease in the required amount would 
clearly diminish the capability of the system to 
promote safety. Neither the comments in gen- 
eral nor any other known data indicate that the 
requirement incorporated in the standard is un- 
feasible. The one comment that sought a change 
in this aspect of the standard contained no detail 
demonstrating that systems in current production 
would be unable to meet the requirement by the 
effective date of the amendment. Consequently, 
the Administrator has decided not to deviate 



PART 571; S 104— PRE 2 



from the adoption of section 2.11 of Recom- 
mended Practice J942, as announced in the notice 
of proposed rulemaking. 

Several comments pointed out the difficulties 
involved in prescribing vriped-area requirements 
for multipurpose passenger vehicles, trucks, and 
buses. The Administrator is cognizant of the 
problems that arise because of the wide variety 
of windshield sizes and configurations as wejl as 
the differing relationships between the drivers' 
positions and the windshields in these vehicles. 
Owing to these factors, he has concluded that it 
is not possible to prescribe uniform wiped areas 
for the wiper systems of these vehicles generally 
or for vehicles within any generic type at this 
time. Hence, the standard's minimum wiped- 
area requirements apply only to passenger cars. 
The possibility of prescribing such requirements 
for other vehicular types will continue to be 
studied. 

In addition, the Administration will also study 
the question of whether there should be standards 
applicable to so-called "hidden" windshield wipers 



tlhOiv: January 1, 1969 

to insure their operability under snow and ice 
conditions. Although a number of comments 
sought the inclusion of such a provision in this 
standard, it was deemed inadvisable to do so 
in view of the absence of any such provision from 
the notice of proposed rulemaking. 

In consideration of the foregoing, § 371.21 of 
Part 371, Federal Motor Vehicle Safety Stand- 
ards, is amended effective January 1, 1969, by 
amending Motor Vehicle Safety Standard No. 
104 

This amendment is made under the authority 
of sections 103 and 119 of the National Traffic 
and Motor Vehicle Safety Act of 1966 (15 U.S.C. 
1392, 1407) and the delegation of authority of 
April 24, 1968. 

Issued in Washington, D.C., on April 24, 1968. 

Lowell K. Bridwell 

Federal Highway Administrator. 

33 F.R. 6466 
April 27, 1968 



PART 671; S 104— PRE 3-4 



Mhcltv*! January I, 1*6* 



PREAMBLE TO AMENDMENT TO MOTOR VEHICLE SAFETY STANDARD NO. 104 

Windshield Wiping and Washing Systems— Passenger Cars, Multipurpose 

Passenger Vehicles, Trucks, and Buses 

(Docket No. 7) 



An amendment to Motor Vehicle Standard No. 
104, which specifies requirements for windshield 
wiping and washing systems in passenger cars, 
multipurpose passenger vehicles, trucks, and 
buses, was issued on April 24, 1968 (33 F.R. 
6466). The amendment is effective January 1, 
1969. 

Paragraph S3 of the amended standard, en- 
titled "Definitions," contains a definition of the 
"plan view reference line" which, as it applies 
to vehicles with individual-type seats, locates the 
line parallel to the vehicle's longitudinal center- 
line so that the 95 percent eye range contour, or 
eyellipse, is geometrically positioned around the 
longitudinal centerline of the driver's designated 
seating position. 

The purpose of the definition, as stated in the 
preamble to the standard, was to position the 
eyellipse geometrically in the center of the seat. 
The Administrator has determined that the defini- 
tion may be construed to permit a different loca- 
tion of the eyellipse, since it provides that the 95 
percent eye range contour must be geometrically 
positioned "around" the longitudinal centerline of 
the driver's seat. Therefore, the definition is 
being amended to clarify the location of the 
eyellipse by requiring its geometric center to be 
positioned on the longitudinal centerline of the 
driver's designated seating position. 

Several petitions for reconsideration of the 
amendment have raised the possibility that the 
definition of plan view reference line may im- 
pose an unintended hardship on manufacturers of 
smaUer cars. The effect of the definition is to 
relocate the eyellipse slightly outboard of the 
location prescribed in the standard prior to the 
amendment. This change may make it imprac- 
ticable for manufacturers of smaller cars to com- 



ply with the wiped-area requirements of the 
standard. Therefore, the definition is being 
further amended to permit optional positioning of 
the eyellipse on the plan view reference line in 
the manner prescribed in the standard prior to 
the previous amendment. 

Neither of these revisions appreciably alters 
the amount of the windshield surface which wip- 
ing systems must wipe under the standard. Hence 
the amendments will have no adverse effect on 
motor vehicle safety. 

Paragraph S4.1.1.3 of the amendment provides, 
in part, that the lowest frequency or speed of 
windshield wiping systems must be at least 20 
cycles per minute regardless of engine speed and 
engine load. The Administrator has received 
petitions asking that a frequency or speed lower 
than 20 cycles per minute be allowed. The peti- 
tioners state that such a lower frequency or speed 
will be useful under conditions of very light 
precipitation or wheel spray, and that retention 
of the 20-cycle-per-minute minimum will preclude 
the use of so-called "intermittent" windshield 
wiping systems. The Administrator has con- 
cluded that the standard should be amended to 
allow manufacturers to vaa systems which can 
operate at a frequency or speed of less than 20 
cycles per minute so long as the driver of the 
vehicle has available a system capable of op- 
erating at at least two other frequencies or speeds, 
differing by at least 16 cycles per minute, the 
lower of which is at least 20 cycles per minute. 
The net effect of this change is to allow as 
many different frequencies or speeds as the manu- 
facturer desires as long as at least two of these 
speeds or frequencies meet the specified require- 
ments. 



PART 671; S 104^PRE 6 



IffKHvai January 1, 1969 

Since these amendments provide clarification, (Sees. 103, 119, National Traffic and Motor 

relieve a hardship and impose no additional Vehicle Safety Act of 1966 (15 U.S.C. 1392, 

burden on any person, notice and public proce- 1470) ; delegation of authority of April 24, 1968 

dure thereon are unnecessary. (33 F.R. 6538) ). 

In consideration of the foregoing, § 371.21 of j^g^^ j^ Washington, D.C., on July 31, 1968. 
Part 371, Federal Motor Vehicle Safety Stand- 
ards, Motor Vehicle Safety Standard No. 104 (32 

F.R. 2410), as amended (33 F.R. 6466), is Lowell K.Bndwell, 

amended, effective July 31, 1968. . . . F«^«™1 Highway Administrator. 

It is found, for good cause shown, that an effec- 
tive date sooner than 180 days after the issuance 33 F.R. 11117 
of these amendments is in the public interest. August 6, 1968 



PART 571; S 104— PRE 6 



MOTOR VEHICLE SAFETY STANDARD NO. 104 
Windshield Wiping and Washing Systems— Passenger Cars, Multipurpose Passenger 

Vehicles, Trucks, and Buses 



51. Scope. This standard specifies 
requirements for windshield wiping and washing 
systems. 

52. Application. This standard applies to 
passenger cars, multipurpose passenger vehicles, 
trucks, and buses. 

53. Definitions. The term "seating reference 
point" is substituted for the terms "manikin H 
point" and "H point" wherever either of those 
terms appears in any SAE Standard or SAE 
Recommended Practice referred to in this 
standard. 

"Daylight opening" means the maximum un- 
obstructed opening through the glazing surface, 
as defined in paragraph 2.3.12 of section E, 
Ground Vehicle Practice, SAE Aerospace-Auto- 
motive Drawing Standards, September 1963. 

"Glazing surface reference line" means the line 
resulting from the intersection of the glazing sur- 
face and a horizontal plane 25 inches above the 
seating reference point, as shown in Figure 1 of 
SAE Recommended Practice J903a, "Passenger 
Car Windshield Wiper Systems," May 1966. 

"Overall width" means the maximum overall 
body width dimension "W116," as defined in 
section E, Ground Vehicle Practice, SAE 
Aerospace-Automotive Drawing Standards, 
September 1963. 

"Plan view reference line" means— 

(a) For vehicles with bench-type seats, a line 
parallel to the vehicle longitudinal centerline out- 
board of the steering wheel centerline 0.15 times 
the difference between one-half of the shoulder 
room dimension and the steering wheel center- 
line-to-car-centerline dimension as shown in 
Figure 2 of SAE Recommended Practice J903a, 
May 1966; or 



(b) For vehicles with individual-type seats, 
either— 

(i) A line parallel to the vehicle longitudinal 
centerline which passes through the center of 
the driver's designated seating position; or 

(ii) A line parallel to the vehicle longitu- 
dinal centerline located so that the geometric 
center of the 95 percent eye range contour is 
positioned on the longitudinal centerline of the 
driver's designated seating position. 
"Shoulder room dimension" means the front 
shoulder room dimension "W3" as defined in 
section E, Ground Vehicle Practice, SAE 
Aerospace-Automotive Drawing Standards, 
September 1963. 

"95% eye range contour" means th 95th percen- 
tile tangential cutoff specified in SAE Recom- 
mended Practice J941, "Passenger Car Driver's 
Eye Range," November 1965. 

S4. Requirements. 

S.41 Windshield wiping system. Each vehicle 
shall have a power-driven windshield wiping 
system that meets the requirements of S4.1.1. 

S4.1.1 Frequency. 

54.1.1.1 Each windshield wiping system shall 
have at least two frequencies or speeds. 

54.1.1.2 One frequency or speed shall be at 
least 45 cycles per minute regardless of engine 
load and engine speed. 

54.1 .1 .3 Regardless of engine speed and engine 
load, the highest and one lower frequency or speed 
shall differ by at least 15 cycles per minute. Such 
lower frequency or speed shall be at least 20 cycles 
per minute regardless of engine speed and engine 
load. 



PART 571; S 104-1 



Table I. Passenger cars of less than 60 inches in overall 
width. 



Column 1 


Column 2 


Column 3 


Column 4 


Column 5 


Column 6 




Minimum 




Angles in 


Degrees 






Percent 

TO BE 










Area 












Wiped 


Left 


Right 


Up 


Down 


A 


80 


16 


49 


7 


5 


B 


94 


13 


46 


4 


3 


C 


99 


7 


15 


3 


1 



Table II. Passenger cars of 60 or more but less than 
64 inches in overall width. 



Column l 


Column 2 


Column 3 


Column 4 


Column 5 


Column 6 




Minimum 




Angles in 


Degrees 






Percent 
to be 










Area 












Wiped 


Left 


Right 


Up 


Down 


A 


80 


17 


51 


8 


5 


B 


94 


13 


49 


4 


3 


C 


99 


7 


15 


3 


1 



Table III. Passenger cars of 64 or more but less than 
68 inches in overall width. 



Column i 


Column 2 


Column 3 


Column 4 


Column 5 


Column 6 




Minimum 




Angles in 


Degrees 






Percent 

TO BE 










Area 












Wiped 


Left 


Right 


Up 


Down 


A 


80 


17 


53 


9 


5 


B 


94 


14 


51 


5 


3 


C 


99 


8 


15 


4 


1 



Table IV. Passenger cars of 68 or more inches in 
overall width. 



Column 1 


Column 2 


Column 3 


Column 4 


Column 5 


Column 6 




Minimum 
Percent 

TO BE 

Wiped 




Ancles in 


Degrees 




Area 


Left 


Right 


Up 


Down 


A 
B 
C 


80 
94 
99 


18 
14 
10 


56 
53 

15 


10 
5 
5 


5 
3 

1 



S4.1.1.4 Compliance with subparagraphs 
S4.1.1.2 and S4.1.1.3 may be demonstrated by 
testing under the conditions specified in sections 
4.1.1 and 4.1.2 of SAE Recommended Practice 
J903a, May 1966. 

S4.1.2 Wiped area. When tested wet in ac- 
cordance with SAE Recommended Practice 
J903a, May 1966, each passenger car windshield 
wiping system shall wipe the percentage of 
Areas A, B, and C of the windshield (established 
in accordance with S4. 1.2.1) that (1) is specified 
in column 2 of the applicable table following 
subparagraph S4. 1.2.1; and (2) is within the 
area bounded by a perimeter line on the glazing 
surface one inch from the edge of the daylight 
opening. 

S4.1.2.1 Areas A, B, and C shall be estab- 
lished as shown in Figures 1 and 2 of SAE 
Recommended Practice J903a, May 1966, using 
the angles specified in Columns 3 through 6 of 
Table I, II, III or IV, as applicable. 

S4.2 Windshield washing system. 

54.2.1 Each passenger car shall have a wind- 
shield washing system that meets the require- 
ments of SAE Recommended Practice J942, 
"Passenger Car Windshield Washer Systems" 
November 1965, except that the reference to "the 
effective wipe pattern defined in SAE J903, para- 
graph 3.1.2" in paragraph 3.1 of SAE Recom- 
mended Practice J942 shall be deleted and "the 
areas established in accordance with subpara- 
graph S4. 1.2.1 of Motor Vehicle Safety Standard 
No. 104" shall be inserted in lieu thereof. 

54.2.2 Each multipurpose passenger vehicle, 
truck and bus shall have a windshield washing 
system that meets the requirements of SAE 
Recommended Practice J942, November 1965, 
except that the reference to "the effective wipe 
pattern defined in SAE J903, paragraph 3.1.2" in 
paragraph 3.1 of SAE Recommended Practice 
J942 shall be deleted and "the pattern design by 
the manufacturer for the windshield wiping sys- 
tem on the exterior surface of the windshield 
glazing" shall be inserted in lieu thereof. 

33 F.R. 6467 
April 27, 1968 



PART 571; S 104-2 



Effective: September 1, 1974 



PREAMBLE TO MOTOR VEHICLE SAFETY STANDARD NO. 105a 

Hydraulic Brake Systems 
(Docket No. 70-27; Notice 5) 



This notice amends Part 571 of Title 49, Code 
of Federal Regulations, to add a new Motor 
Vehicle Safety Standard No. 105a (49 CFR 
§ 571.105a) that establishes requirements for 
motor vehicle hydraulic brake systems and park- 
ing brake systems. A notice of proposed rule- 
making on this subject was published on Novem- 
ber 11, 1970 (35 F.R. 17345). 

Federal Standard No. 105, in effect since Jan- 
uary 1, 1968, represents the initial Federal effort 
to specify braking requirements for motor ve- 
hicles. The standard requires that passenger 
cars be equipped with a split service brake sys- 
tem, and have stopping ability based upon de- 
celeration rates specified in an SAE Recom- 
mended Practice. Requirements for fade and 
recovery, water recovery, and stability while 
braking are also included in the standard. These 
requirements do not, however, represent the full 
capabilities of modern braking technology. 
Braking continues to be the most important 
single element of accident avoidance from the 
standpoint of vehicle performance. The full 
utilization of the industry's technological capa- 
bility in this area, within the limits of reasonable 
cost, is therefore of highest importance to the 
safety effort. 

The requirements of this standard are specified 
in terms of performance on a surface of rela- 
tively high skid number. The NHTSA recog- 
nizes the importance to safety of good braking 
performance on surfaces such as wet or icy roads. 
It is monitoring closely the development work 
in progress on methods, such as antilock systems, 
designed to enhance vehicle performance over a 
wide variety of surfaces, in preparation for fu- 
ture rulemaking action adding performance re- 
quirements in this area. Until such requirements 
are made effective, this agency assumes that 



manufacturers will design their vehicles for safe 
braking performance on all types of road sur- 
faces, while continuing to work on, and make 
provision for, more advanced braking systems. 

The notice issued in November 1970 proposed 
extension of applicability of Standard No. 105 
to other vehicle types and covered the same fac- 
tors deemed important in the earlier standard. 
These include stopping distance, Imear stability 
while stopping, fade resistance, and fade recov- 
ery. The notice also proposed features in hy- 
draulic braking systems that could warn against 
malfunction, and stop the vehicle should a mal- 
function appear in the normal service system. 
The amended standard' covers each of these as- 
pects as discussed below. 

1. Applicability. Standard No. 105 applies to 
passenger cars, and has been extended to specify 
requirements for the first time for multipurpose 
passenger vehicles, trucks, and buses equipped 
with hydraulic brake systems. A definition of 
brake power unit has been adopted and appro- 
priate modifications made in the text to clarify 
that vehicles with central hydraulic power sys- 
tems were included in the Notice. Standard No. 
105a does not apply to vehicles equipped with 
"air over hydraulic" systems, which remain 
within the purview of Standard No. 121, Air 
Brake Systems. 

2. Effective date: to meet the proposed effec- 
tive date of October 1, 1972, equipment and 
performance requirements would have been sub- 
stantially weaker than those that have been 
adopted and the NHTSA has determined that a 
later effective date is, overall, in the public in- 
terest. It is therefore set at September 1, 1974. 

3. Service hrake system. All vehicles with hy- 
draulic brake systems are reauired to have a 



PART 571; S 105 —PRE 1 



EffMliv*: S«ptamb«r I, 1974 



split service brake system, with partial failure 
or "emergency" braking features. Effectiveness 
of the system is demonstrated by a series of road 
tests covering stopping distance, stability, and 
fade and recovery, water recovery, and spike 
stops. 

A. Stopping distance. As the proposal noted, 
"perhaps the most important indication of brake 
performance is the distance in which a brake 
system can stop a vehicle from a given speed." 
Stopping distances were proposed from 30 mph, 
60 mph, and 80 mph and maximum attainable 
vehicle speed, under various load and system 
conditions, based upon vehicle category or weight. 
These tests included stops with the vehicle at a 
lightly loaded weight, and stops under partial 
failure conditions. The following illustrate ex- 
amples of the proposal and amendment. In ad- 
dition to the stopping distances discussed below, 
stopping distances from 30 mph, 80 mph, and 
maximum attainable vehicle speed are also speci- 
fied. 

Passenger cars. It was proposed that passen- 
ger cars demonstrate the ability to stop in 185 
feet from 60 mph under adverse loading condi- 
tions. The stopping distance adopted, 194 feet, 
is only slightly longer. According to Consumer 
Information data submitted by manufacturers of 
1972 passenger cars, contemporary vehicles 
ranked 26th to 61st would be unable to meet this 
stopping distance requirement. This new re- 
quirement will result in a substantial upgrading 
of passenger car stopping ability. Currently 
under Standard No. 105, passenger cars must 
demonstrate the ability to stop in 646 feet from 
60 mph under partial failure conditions. The 
new standard lowers this distance to 431 feet, 
an increase from the proposed 388 feet. The 
same stopping distance requirement must be met 
with an inoperative brake power assist or brake 
power unit. 

Vehicles with GVWR of lOfiOO pounds or less. 
Vehicles other than passenger cars with a gross 
vehicle weight rating of 10,000 pounds or less, 
must demonstrate the ability to stop from 60 
mph in 216 feet under adverse loading condi- 
tions, and in 484 feet under partial failure 
conditions. 

Vehicles with GVWR greater than 10,000 
pounds. • Vehicles in this category must demon- 



strate an ability to stop from 60 mph in 245 feet 
under adverse loading conditions, and in 553 feet 
under partial failure conditions. 

B. Stability of vehicle while stopping. As 
proposed, a vehicle will be required to stop 
(other than in spike stops) without any part of 
it leaving a 12-foot-wide lane. Wheel lockup is 
permitted at a speed below 10 mph and lockup 
of only one wheel not controlled by an antilock 
system is permissible at speeds in excess of 
10 mph. 

C. Fade and recovery. Brake fade character- 
istics are critical from the standpoint of retaining 
adequate stopping power despite the high tem- 
peratures created by prolonged or severe use. A 
vehicle will demonstrate fade and recovery capa- 
bility in two tests, by making a number of fade 
stops from 60 mph if it is a vehicle with a GVWR 
of 10,000 pounds or less, or fade snubs from 40 
mph to 20 mph, if it is a heavier vehicle. The 
latter represents a modification of the proposed 
snub speed range of 50 mph to 15 mph. The 
proposed maximum speed fade recovery test has 
not been adopted; the effectiveness test at maxi- 
mum attainable vehicle speed should indicate 
whether a brake system will experience problems 
with fade. 

D. Water recovery. Service brake systems must 
also demonstrate an acceptable recovery after 
exposure to water. The method of immersion 
has been modified on the basis of comments that 
the method proposed would necessitate use of a 
trough 880 feet long. Instead, the amendment 
specifies that the vehicle shall be driven for not 
less than 2 minutes at a speed of 5 mph, in any 
combination of forward and reverse directions, 
through a trough having a water depth of 6 
inches. This change should clarify the test re- 
quirement as well as simplifying enforcement 
procedures. 

E. Spike stops. The spike stop proposal has 
been adopted, with a revision to allow 6 check 
stops (instead of one), at least one of which 
meets the requirements of the specified distance 
and pedal force. This allowance recognizes 
variability of test drivers and vehicles. 

4. Parking brake system. The parking brake 
system proposal has also been adopted. When 
the parking brakes are applied, with a force not 
exceeding 90 pounds for a hand-operated system 



PART 571; S 105 —PRE 2 



EffMtIv*: Stptambar 1, 1974 



or 125 pounds for a foot-operated system, the 
parking brake system shall be capable of holding 
the vehicle stationary for 5 minutes on a 30 per- 
cent grade (20 per cent for vehicles of more 
thh.n 10,000 pounds GVWR) in both forward 
and reverse directions. Optional requirements 
have been adopted for vehicles with a GVWR 
of 10,000 pounds or less, equipped with a trans- 
mission utilizing a parking pawl or detent mech- 
anism within the transmission assembly. Vehicles 
so equipped may demonstrate compliance by 
(1) parking with both the parking brake and 
pawl engaged on a 30 per cent grade, (2) park- 
ing on a 20 per cent grade with only the parking 
brake engaged, and (3) being impacted front 
and rear, on a level surface, by a 4,000 pound 
moving barrier without disengagement or frac- 
ture of the pawl or detent mechanism. 

5. Reservoirs. The master cylinder reservoir 
proposal has been adopted with modifications 
that allow balance ports and compartmentalized 
reservoirs in a single integrated master cylinder 
body and reservoir assembly, and that reduce 
fluid reservoir capacity requirements from 150 
per cent to 100 per cent. The proposed cover, 
seal, and retention devices have not been adopted 
since pressure differential warning and low fluid 
level warning should provide a suflicient safety 
factor. The proposal was intended also to cover 
reservoir requirements in systems not using 
master cylinders and the revised wording of the 
section clarifies this point. 

6. Brake system indicator lamp. The proposal 
would have required separate lamps to indicate 
when the parking brake is applied, and when a 
failure has occurred in the service brake system. 
Standard No. 105a requires only one lamp to 
serve these functions, to be labeled "Brake". 
Either the wording or the lens may be the color 
red. The lamp must light in the event of pres- 
sure failure in any part of the service brake 
system, other than a structural failure of a hous- 
ing that is common to two or more subsystems, 
before or upon application of 50 pounds of pedal 
force upon a manually-operated service brake, 
or 25 pounds upon a service brake with a brake 
power assist unit, or when the supply pressure 
in a brake power unit drops to not less than one- 
half of the normal system pressure. The lamp 
must also light, without the application of pedal 



force, when the level of brake fluid in the master 
cylinder reservoir drops to less than the recom- 
mended safe level specified by the manufacturer, 
or to not less than one-fourth the fluid reservoir 
capacity in any reservoir compartment, which- 
ever is greater. This does not preclude the use 
of translucent covers or sight gauges in addition 
to the required lamp. Additionally, the lamp 
must illuminate when there is a total electrical 
failure in an antilock or brake proportioning 
system. All indicator lamps shall be activated 
when the ignition switch is turned from the "on" 
to the "start" position, which includes the air 
start condition on diesel-engine vehicles. The 
lamps will be deactivated upon return of the 
switch to the "on" position. No time interval is 
specified for deactivation, as the NHTSA recog- 
nizes that instant deactivation is impracticable 
for continuous sensing units. 

7. Miscellaneous. The NHTSA proposed that 
service brakes be installed so that the lining 
thickness of drum brake shoes and disc brake 
pads might be visually inspected without remov- 
ing the drums or pads. The possibility that 
contaminants may enter the system if plugs are 
removed, the differences between riveted and 
bonded lining thickness, and the location of in- 
spection ports, were some of the technical and 
safety factors weighing in the conclusion to 
abandon this proposal. 

The agency decided against the proposal that 
would have established suspension system dur- 
ability requirements to be met following comple- 
tion of tests. Since the vehicle must remain 
within a 12-foot-wide lane as a condition of the 
stopping distance tests, this will be a satisfactory 
demonstration of suspension system integrity. 

Effective date: September 1, 1974. Because 
of the necessity to allow manufacturers suflScient 
production leadtime, it is found for good cause 
shown that an effective date later than one year 
after issuance of this rule is in the public interest. 

In consideration of the foregoing, Title 49, 
Code of Federal Regulations, is amended by 
adding § 571.105a, Motor Vehicle Safety Stand- 
ard No. 105a, Hydraviic Brake Systems, as set 
forth below. 

This notice is issued under the authority of 
sections 103 and 119 of the National Traffic and 



PART 671 ; S 106 —PRE 8 



EfNcHva: S«pt«mb«r I, 1974 



Motor Vehicle Safety Act of 1966 (15 U.S.C. Issued on : August 23, 1972. 

1392, 1407) and the delegation of authority from Douglas W. Toms 

the Secretary of Transportation to the National Administrator 

Highway Traffic Safety Administrator, 49 CFR 37 F.R. 17970 

^f^l September 2, 1972 



PART 571; S 106 —PRE 4 



Effcctiv*: StpUmbtr 1, 1975 



PREAMBLE TO AMENDMENT TO MOTOR VEHICLE SAFETY STANDARD NO. 105a 

Hydraulic Brake Systems 
(Docket No. 70-27; Notice 7) 



The purpose of this notice is to announce that 
the effective date of Motor Vehicle Safety Stand- 
ard No. 105a will be September 1, 1975. Full 
response to petitions for reconsideration is sched- 
uled for May 1, 1973. 

Standard No. 105a, Hydraulic Brake Systems, 
was published on September 2, 1972 (37 F.R. 
17970 with corrections at 37 F.R. 19138) with an 
effective date of September 1, 1974. On Decem- 
ber 19, 1972, the NHTSA advised (37 F.R. 
27629) that it intended to issue a notice by Feb- 
ruary 1, 1973, in response to petitions for recon- 
sideration of the standard. The volume of the 
petitions received and the complexity of the 
issues involved are such that the agency has not 
found it possible to publish a full response to the 
petitions by the date indicated. 

The NHTSA has, however, decided to grant 
petitions requesting a delay in the effective date, 
to the extent of a one-year postponement. Peti- 
tioners have demonstrated to the satisfaction of 
the agency that because of critical lead-time 



problems the original effective date is impractic- 
able. The NHTSA believes that in the addi- 
tional year provided the industry will have 
sufficient time to increase the reliability of the 
systems that otherwise would have been incor- 
porated beginning September 1, 1974, with the 
result that consumers will be provided with brak- 
ing systems that have been optimized with re- 
spect to safety, performance, and cost. 

The full response and discussion of issues raised 
by the petitioners is planned for issuance by 
May 1, 1973. 

(Sec. 103, 119 P.L. 89-563, 80 Stat. 718, 15 
use 1392, 1407; delegation of authority at 49 
CFR 1.51). 

Issued on January 30, 1973. 

Douglas W. Toms 
Administrator 

38 F.R. 3047 
February 1, 1973 



PART 571; S 105 —PRE 5-6 



EffacHvs: S*pl«mb*r 1, 1975 



PREAMBLE TO AMENDMENT TO MOTOR VEHICLE SAFETY STANDARD NO. TOSa 

Hydraulic Brake Systems 
(Docket No. 70-27; Notice 8) 



This notice responds to petitions for reconsid- 
eration of Motor Vehicle Safety Standard No. 
105a and amends the standard in certain re- 
spects, eflFective September 1, 1975. 

Federal Motor Vehicle Safety Standard No. 
105a, 49 CFR § 57l.l05a, was published on 
September 2, 1972 (37 F.R. 17970). Thereafter, 
pursuant to 49 CFR § 553.35 petitions for recon- 
sideration of the rule were received from many 
interested corporations. A discussion of the 
major issues raised by the petitions and their 
resolution follows. 

1. Policy. Several petitioners questioned the 
need for stringent braking requirements. The 
claim was made that NHTSA has shown neither 
a need based on accident data relating brake 
performance to deaths, injuries, or property 
damage, nor the benefits to be obtained from 
changed braking systems. Additionally, com- 
ments were received that most consumers could 
not utilize enhanced braking capabilities under 
most circumstances. Some also questioned the 
cost to implement the standard (allegedly $40 
an average per vehicle as a minimum, and up to 
$75 in some instances for passenger cars). 

The NHTSA does not agree with its critics on 
these policy issues. Braking system performance 
has consistently rated high on the safety critical- 
ity list. The dominance of the role of braking 
systems in accident avoidance maneuvers has 
long been recognized and undisputed. The im- 
portance of braking in motor vehicle safety is 
evidenced by the fact that of all vehicle defects 
which cause or contribute to accidents, brake 
failures lead the list. In the Consumer Infor- 
mation data on braking stopping distances pro- 
vided by the automobile manufacturers, the 
better performing vehicles are reported to stop 



from 60 mph in slightly more than one half the 
distance of the poorer performing vehicles. 
Large stopping distance differentials among ve- 
hicles operating in a common traffic stream are 
recognized as creating serious hazards to the 
motorist. 

Data have shown that in many accidents a 
more effective service brake system would have 
lessened the severity of the collision or possibly 
averted it. Existing vehicles in many instances 
do have good braking capabilities but require 
excessive control forces to utilize these capabili- 
ties. Many drivers are not able to exert these 
forces and hence do not utilize existing systems 
to the fullest. With reduced stopping distances 
within the specified pedal forces required by 
Standard No. 105a, it is the opinion of NHTSA 
that deaths, injuries, and property damage will 
be reduced. 

Since the requirements also specify that the 
stopping distances shall be achieved with the 
vehicle under control, stopping without locked 
wheels in a 12-foot-wide roadway lane, motorists 
will be afforded a greater opportunity to operate 
their brakes effectively in accident avoidance 
maneuvers. 

Cost estimates submitted by petitioners are in 
agreement with those of the NHTSA. Based 
upon the information received from petitioners 
and the changes made as a consequence thereof, 
however, it is the opinion of this agency that the 
cost of implementation will be reduced to a figure 
commensurate with the safety benefits expected 
to be derived. 

With respect to the performance levels speci- 
fied, the NHTSA has determined that the values 
are reasonable and do not exceed the inherent 
capabilities of any of the various vehicle classes. 



PART 571; S 105 —PRE 7 



Effective: September 1, 1975 



The values specified for vehicles other than pas- 
senger cars will considerably reduce the existing 
stopping distance differentials among vehicle 
classes. 

Several petitioners commented on what they 
considered to be a lack of consistency in perform- 
ance levels between vehicle types. For example, 
in the second effectiveness test, passenger cars, 
light trucks and heavy trucks have different per- 
formance requirements based upon weight and 
speed. Standard No. 105a was criticized also 
because the required stopping distances for heavy 
trucks with hydraulic brakes were more stringent 
than recjuirements for heavy trucks with air 
brakes (Standard No. 121, Air Brake Systems). 
It was argued that requirements should be the 
same for similar vehicles regardless of the type 
of brake system. Petitioners requested that par- 
tial failure system requirements, and require- 
ments for failed power units, be identical to 
those for air-braked vehicles. 

Other petitioners requested that emergency- 
type tests should allow locked wheels as in Stand- 
ard No. 121. Petitioners, in several instances, 
requested changes in light load test requirements 
for the various vehicles. These requests were 
based on differences in load conditions, inertia 
load differences in stopping, center of gravity 
locations, and braking balance differences. 

The standard has been amended to recognize 
the changes in performance due to vehicle weight 
differences, considering the effects of center of 
gravity location and weight shifts occurring 
during decelerations. Also, speed sensitivity 
effects have been recognized as occurring in all 
vehicles and appropriate modifications in re- 
quirements at the various test speeds have been 
made. Heavy vehicle requirements have been 
adjusted where appropriate to make them identi- 
cal to those existing in Standard No. 121. Some 
differences have been retained, however. For 
example, fade tests in Standard No. 105a are run 
on the vehicle in a road test as compared with a 
dynamometer test in Standard No. 121. Dyna- 
mometer tests were selected in Standard No. 121 
since vehicles used primarily in combinations are 
included in that standard. Compatibility be- 
tween vehicles (tractor and trailer) was consid- 
ered to be an important factor in the brake 



system evaluation and could most easily be de- 
termined on the dynamometer. 

Revisions to Standard 105a also have been 
made to allow wheel lockup on emergency-type 
tests such as spike stops, tests with failed power 
units, and partial system tests. Also, in the 
parking brake test, the limit of traction of the 
braked wheels is used in specifying parking 
brake system performance on a .SO per cent grade. 
There are no changes in parking braking system 
requirements because of weight differences. The 
NHTSA is of the opinion that all vehicles, re- 
gardle.ss of weight class, are frequently parked 
in a lightly loaded condition and hence should 
be tested under this condition. 

2. Effective date. The NHTSA has previously 
announced an overall delay of one year in the 
effective date of Standard No. 105a (38 F.R. 
3097). 

Petitioners generally considered the original 
effective date of September 1, 1974, to be un- 
reasonable and impracticable. The earlier effec- 
tive date as it applied to trucks, buses and 
multipurpose passenger vehicles coincided with 
the same effective date for Standard No. 121, 
issued some time before Standard No. 105a. The 
air brake systems will generally have new and 
larger foundation brakes, new suspensions and 
other related components, antilock or brake pro- 
portioning systems and new split systems as well 
as controls. Hydraulic-braked vehicles require 
in most instances similar changes to meet 105a 
requirements. However, manufacturers and sup- 
pliers had prior commitments to concentrate 
much of their available manpower, equipment 
and facilities to the development of conforming 
air brake systems. These manpower, equipment, 
and facilities are generally the same required for 
the development of conforming hydraulic-braked 
vehicles, and thus the changes to hydraulic- 
braked vehicles cannot be made simultaneously 
with air brake system changes. In addition, 
sufficient recognition must be given to the lead- 
time necessary for application studies, production 
standardization in areas where this is possible, 
drawing and specification preparation, tooling 
design time and procurement, and establishing 
manufacturing facilities. In some instances, 
plant facilities must be built along with con- 



PART 571; S 105 —PRE 8 



Effactiv*: Saplembar 1, 1975 



struction of development and test facilities. Pe- 
titioners also mentioned the significance of 
reduced product reliability if it is necessary to 
completely redesign entire vehicle lines simul- 
taneously. Additional problems that can arise 
are related to the capability of the manufactur- 
ers to train adequately technical personnel to 
assemble, service, and maintain the new vehicles. 

Several petitioners requested an extension of 
the effective date for vehicles other than passen- 
ger cars beyond September 1, 1975. International 
Harvester requested a date of September 1, 1976 
for these vehicles. Others would not predict a 
date on which they could meet the requirements. 

Several commenters stressed the fact that me- 
tallic, semi-metallic, or ceramic linings, considered 
exotic materials presently, would probably be 
required to meet Standard No. 105a as of Sep- 
tember 1, 1974. Resulting penalties would occur 
in cost (high wear, scoring, etc.) and poor or 
erratic performance under normal conditions. 

Comments were also received concerning four- 
wheel drive vehicles. Low volume and conse- 
quent high costs for necessary changes are prob- 
lems in this segment of the industry. Suppliers 
of components for these vehicles are allegedly 
reluctant to design and tool parts. In addition, 
manpower and facilities are not available for 
these jobs since most time and efforts must be 
utilized for the higher volume vehicles. An in- 
definite delay in an effective date for these ve- 
hicles has been requested. 

After careful evaluation of all the petitions, 
the NHTSA considered that good cause had been 
shown for a delay of one year in the effective 
date of the standard. But it has been determined 
that a further delay, either for the standard or 
for separate vehicle categories is not in the in- 
terest of motor vehicle safety, and those petitions 
for a further extension of time are denied. 

3. DefirdtioTis. Numerous comments were re- 
ceived on the definitions. In some instances 
amendments are made, in others, none. Clarifi- 
cations have been provided where they were 
requested. 

Questions relating to brake power assist units 
and brake power units have been raised. The 
distinction between the two is that a brake power 
assist unit has a push-through capability, i.e., the 



operator can apply additional muscular effort and 
obtain braking action. A brake power unit does 
not have this capability. If power is lost, a 
driver cannot increase braking force by addi- 
tional muscular effort on the control. 

Some petitioners mentioned units which func- 
tion in both modes, i.e., as a brake power unit in 
one condition, and as a brake power assist unit 
in a second condition. For example, a unit may 
function as a brake power unit under normal 
operating conditions, but when a power failure 
occurs, it operates as a brake power assist unit. 
For purposes of compliance, the failed mode of 
operation would be the critical mode. Therefore, 
with inoperative power units, the test require- 
ments should be met depending on how the sys- 
tem operates in the failed mode. The example 
discussed above would be tested as a brake power 
assist unit. 

The definition of "brake proportioning system" 
raised the question whether a fixed or variable 
system was intended. The term has been redes- 
ignated -'variable brake proportioning system" to 
clarify the agency's intent. 

The definition of "lightly loaded vehicle" does 
not specify an additional weight allowance for a 
load platform or body to be added to an incom- 
plete vehicle, but in the opinion of .some peti- 
tioners it should. Since the standard applies to 
complete vehicles, a manufacturer must use his 
discretion in applying additional weight to in- 
complete vehicles, taking into account the result- 
ing changes in weight and center of gravity, 
when providing information on Standard No. 
105a to subsequent multistage vehicle manufac- 
turers. 

Some manufacturers questioned the adequacy 
of the test surface specification: the "skid num- 
ber" produced by American Society for Testing 
and Materials Method E-274, using a test trailer 
to measure the coefficient of friction. The com- 
plaint was made that the measurement results 
vary from one trailer to another, and vehicle 
performance results vary from one surface to 
another with supposedly the same skid number, 
on the order of 20 percent. It was also argued 
that the ASTM test was qualitatively inadequate, 
in that it measured sliding friction rather than 
peak or incipient friction. 



PART 571; S 105 —PRE 9 



Effecllva: Stptamber 1, 1975 



The NHTSA does not accept these arguments. 
In the first place, it should be noted that thrust 
of the manufacturers' arguments is not only to 
abort this rulemaking, but to cast doubt on the 
validity of the existing braking standard. What- 
ever its shortcomingc, the ASTM test is the only 
one to the knowledge of tliis agency that provides 
an objective and quantitative measure of the 
frictional characteristics of a road surface, and 
no other was suggested by petitioners. The 
present passenger car braking standard incor- 
porates an SAE Recommended Practice (J843d) 
that specifies only a "dry, smooth, hard-surfaced 
roadway of Portland cement concrete (or other 
surface with equivalent coefficient of surface 
friction) that is free from loose materials," a far 
vaguer description. 

Furthermore, the NHTSA does not find the 
argument based on variations in test results to 
be persuasive. The variations of 15 and 20 per- 
cent cited are extreme figures. With carefully 
calibrated and controlled test instruments and 
conditions, as specified in the standard, evidence 
before this agency indicates that the normally 
experienced variations are much smaller. Manu- 
facturers have attempted to impose a criterion 
of perfect repeatability on the safety standards. 
Perfect repeatability, however, is an illusion. In 
the "real world" of materials testing, particularly 
of gross characteristics such as vehicle braking 
capability or crashworthiness, variation in re- 
sults is inevitable; the question is not whether, 
but how much, variation is acceptable. Ob- 
viously, the standard should be designed to rea- 
sonably minimize the variability of test results, 
from the standpoint both of manufacturing costs 
and of effective regulation. 

In this case, the ASTM method chosen was 
developed in 1965, and has been widely used since 
then for the purpose of vehicle performance 
testing. Moreover, it has been in force since 
1970 in a closely similar NHTSA regulation: 
the Consumer Information regulation on Vehicle 
Stopping Distance (49 CFR 575.101), under 
which manufacturers have been required to test 
their vehicles' stopping-distance capabilities, and 
report them to consumers and to the NHTSA. 
The same statutory penalties have applied to a 
failure to meet these reported stopping distances 
when tested by the government as would apply 



to a failure to meet the stopping distance re- 
quired by a standard. In light of these factors, 
the arguments that the method for specifying 
the test surface is inadequate are found to be 
without merit. 

The NHTSA also rejects the suggestion by the 
Recreational Vehicle Institute that this agency 
should supply or measure the test surface, be- 
cause of the limited capabilities of motor home 
manufacturers. The clearly intended result of 
the National Traffic and Motor Vehicle Safety 
Act is that the private sector should bear the 
cost of regular conformity and certification test- 
ing. There is no requirement that each vehicle 
manufacturer have his own measured test track. 
Small manufacturers can have their vehicles 
tested by contract with testing companies; they 
can use their trade associations to arrange for 
use of measured test tracks in convenient regional 
locations; or they can work with the chassis 
manufacturer and use his test results. 

The sudden application of force in a "spike 
stop" is 200 pounds applied in 0.08 second. 
Chrysler Corporation suggested a "band" of 
0.05-0.20 seconds as permitted in SAE Recom- 
mended Practice J229 Service Brake Structural 
Integrity Test Procedure, March 1971. The 
purpose and legal significance of a test condition 
in a Federal motor vehicle safety standard are 
different from those of an industry test practice, 
and a band or tolerance as requested by Chrysler 
is inappropriate and unnecessary in the former. 
Assuming that a faster application is more de- 
manding of vehicle performance, Chrysler in 
effect has a band from to 0.08 second for its 
tests, which should be designed to show that the 
vehicle is capable of meeting the requirements 
with spike stops of 0.08 second. 

The definition of "stopping distance" varied 
from the notice of proposed rulemaking in that 
the phrase "start of the brake application" was 
changed to "point of application of force to the 
brake control." Wagner Electric Co. considers 
the modified definition as more stringent since, 
in its view, the notice allowed both "force" and 
"movement" while the amendment allows only 
the former. The NHTSA disagrees with Wag- 
ner. Both versions refer purely to the brake 
pedal, and not to more remote parts of the brake 



PART 671; S 106 —PRE 10 



EffecHve: September 1, 1975 



system. This agency is unaware of any measur- 
able difference in time between the introduction 
of force to the pedal and the initiation of pedal 
movement, and Wagner has supplied no evidence 
to the contrary. The modified wording has been 
adopted for purposes of clarity. 

Greneral Motors objected to stopping distances 
as performance requirements, and expressed its 
views that deceleration rates provide more ob- 
jective performance criteria. This represented a 
departure from GM's previous views that build- 
up and maintenance of a fixed deceleration 
depended upon varying driver skills, affecting 
reproducibility. The variety in driver skills is 
one reason the NHTSA considers measurement 
of a specified distance more desirable than main- 
tenance of a fixed deceleration rate. Insertion 
of a fixed build-up time would introduce a com- 
plication. The stopping distances specified do 
not include a fixed build-up time but instead 
allow use of various characteristics, including 
greater or lesser build-up times, as long as the 
vehicle does not exceed the stopping distance 
specified. A specified maximum (but not fixed) 
build-up time is used in fade tests where decele- 
rations are specified. Further, the distances 
expressed in Standard No. 105a are maximum 
distances, and manufacturers will necessarily 
design their vehicles to perform with a margin 
within those limits, thus reducing problems of 
objective measurement. 

4. Required stopping distances and pedal con- 
trol forces. The stopping distance values, in 
most instances, were considered by petitioners to 
require redesigned braking systems. In some 
cases, larger brake systems would be required, 
incorporating front disc brakes with power assist 
and larger rear drum brakes. Other vehicles, 
particularly trucks, buses, and multipurpose pas- 
senger vehicles, would require the addition of 
antilock systems or brake proportioning systems, 
along with new types of split systems (or com- 
pletely redundant systems). These systems, it 
is alleged, would be required to meet the full 
system effectiveness and the partial system effec- 
tiveness requirements. 

The 30 mph and maximum speed stopping 
distances were considered too stringent by most 
petitioners. The very short stops involved, along 



with the buildup or actuation time necessary, 
were the main problems in the 30-mph tests. 
The problem of the speed sensitivity of lining 
materials was the main factor noted in comments 
relating to the high speed and maximum speed 
tests. 

For first effectiveness test, recommended 
changes in stopping distances ranged at 30 mph 
from no increase to an increase of 9 feet for 
passenger cars, 7 feet for light trucks, and 20 
feet for heavy trucks. At 60 mph, requests for 
increases of up to 17 feet for passenger cars, 
7 feet for light trucks, and 75 feet for heavy 
trucks were received. Two petitioners suggested 
deleting heavy truck requirements, either to be 
consistent with Standard No. 121 or until "more 
realistic data" was available. 

The second through fourth effectiveness tests 
were more severely criticized by petitioners. 
Several suggested that fourth effectiveness test 
values be increased to at least those used in the 
first effectiveness tests (involving increases of 
5, 7 and 10 feet at 30 mph, and changes of 20, 
26, and 32' feet at 60 mph, for passenger cars, 
light trucks and heavy trucks, respectively). 
Several commenters recommended deletion of 
tests at speeds greater than 80 mph. For light 
and heavy trucks, maximum speeds of 60 mph 
to 80 mph were recommended. 

Certain modifications in stopping distances 
and test speeds have been made in response to 
these comments. The maximum test speed for a 
vehicle with a GVWR that exceeds 10,000 pounds 
has been reduced from 80 mph to 60 mph. The 
maximum test speed will be 100 mph, specified 
only for those passenger cars which attain a 
speed of 104 mph or greater in 2 miles. If the 
speed that a passenger car is capable of attaining 
in 2 miles is from 99 to 104 mph, its maximum 
test speed will be 95 mph. Intermediate test 
speeds between 80 and 95 mph, and 60 and 80 
mph have also been eliminated for all vehicles; 
thus if a vehicle's top speed is from 84 to 99 
mph, its top test speed is 80 mph; if the top 
speed is from 64 to 84 mph, its top test speed is 
60 mph. Stopping distances have been increased 
slightly in most instances from those previously 
required; an example is the second effectiveness 
test where the 60-mph stopping distance for pas- 



PART 571; S 105 —PRE 11 



E«N<llv«: September I, 1975 



senger cars at GVAVR will be 204 feet rather 
than 194. Under partial failure conditions at 
the same speed, the stopping distance for pas- 
jsnger cars has been increased from 431 to 456 
feet. 

Standard No. 105a required stops to be made 
at pedal forces that varied from 15 to 100 pounds 
at stops from 30 mph, to 20 to 150 pounds at 
stops from 65 mph or higher. Pedal control 
force values were objected to and requests for 
changes were made, ranging from an increase 
at 30 mph to 120 pounds to an across the board 
increase to 150 pounds maximum for all tests. 
Petitions were based generally on the need either 
to allow higher pedal forces to reduce brake 
sensitivity or to provide a simple single value 
for all tests. A change to allow 200 pounds of 
maximum pedal force on parking brake tests for 
light trucks was also requested. Several peti- 
tioners also requested modifications in fade re- 
covery test pedal force values. 

The NHTSA considers that most of these re- 
quests are meritorious. The standard is being 
amended to specify a uniform force range of 
16 to 150 pounds for all stops that must be made 
within required stopping distances, and this will 
be expressed as a test condition in paragraph S6. 
However, the parking brake test pedal forces 
must, in the opinion of the NHTSA remain 
uniform at 125 and 90 pounds (foot and hand) 
and the petition on this point is denied. General 
Motors requested a force for the 5th (final) fade 
recovery stop that is within plus 50 pounds and 
minus 5 pounds or minus 40 percent (whichever 
is greater) of the average control force for the 
baseline check. These values are considered too 
broad. Some relief is deemed warranted, how- 
ever, and Japan Automobile Manufacturers As- 
sociation's suggested value of minus 10 pounds 
has been adopted. 

5. Inoperative power units. In addition to the 
requests for clarification between brake power 
assist units and brake power units petitioners 
requested changes in requirements that would 
recognize the reserve capabilities that have been 
designed into the inoperative mode of some power 
systems. These petitions have been granted, and 
tests with an inoperative brake power unit or 
power assist unit have been modified to allow 



optional utilization of reserve capabilities in 
stopping. Under the optional procedure a ve- 
hicle makes a series of stops from 60 mph at 
specified decelerations when the inoperative unit 
is not initially depleted of all reserve capability 
and in a final stop within 554 feet when the unit 
has been depleted of its reserve. 

6. Fade and recovery requirements. Standard 
No. 105a required that vehicles with a GVWR 
of 10,000 pounds or less demonstrate fade re- 
sistance in two fade and recovery tests of 10 and 
15 stops each from 60 mph at 15 fpsps. 

Fade and recovery requirements were consid- 
ered extremely stringent by petitioners. Several 
petitioners suggested a reversion to the existing 
requirements with minor modifications. Others 
suggested changes in test weights. Most were 
willing to accept the 150-pound pedal force 
limitation if other modifications proposed were 
acceptable. GM recommended that two different 
fade test procedures be adopted, the first simu- 
lating a mountain type fade test at GVWR with 
increased distance intervals, and the second being 
similar to that adopted except at a reduced test 
load. 

These petitions have been deemed in large 
part to have merit, and the two fade tests will 
be revised to consist of 5 and 10 fade stops at 
15 fpsps, each followed by an additional 5 stops 
at the maximum deceleration attainable between 
5 and 15 fpsps. The fade test requirements for 
vehicles with a GVWR in excess of 10,000 pounds 
remains unchanged. However, no procedure 
simulating mountain descents has been developed, 
and GM's request is denied. International 
Harvester, in the fade test procedure, requested 
that the time to attain the required deceleration 
presently 1 second, be increased to 5 seconds. 
This request is denied, since an increase has been 
found unnecessary. 

7. Water recovery. GM petitioned for sub- 
stantial changes in the water recovery test, ask- 
ing relocation within the test sequence, modified 
control forces, and increassed number of recovery 
stops for heavy trucks. None of these requests 
has been found to have merit. A change in se- 
quence would necessitate reevaluation of the 
effect of the standard with a possible consequent 
further delay in the effective date. 



PART 571; S 105 —PRE 12 



Effacllva: Sapl«mber 1, 1975 



8. Spike stops. With regard to the spike stop 
requirements, Bendix requested that the stopping 
distance for the effectiveness (check) stops be the 
equivalent of the first effectiveness test rather 
than that of the other effectiveness tests. The 
request has merit, and the stopping distance re- 
quirements of the first effectiveness test have 
been adopted. 

GM requested that for the spike stop test 
manufacturers be allowed to use separate vehicles 
not used in the other tests, while Harvester re- 
quested a reduction in stopping speed from 60 
mph to 30 mph. Because of the changes in stop- 
ping distance that have been adopted, no further 
relief is deemed necessary and the petitions are 
denied. 

9. Parking 'brake systems. The parking brake 
system requirements, particularly in the lightly 
loaded vehicle condition, were objected to as 
violating the laws of physics. As mentioned 
earlier, petitioners generally requested inclusion 
of a "limit of traction" condition. Vehicles with 
a great range of loading conditions are allegedly 
incapable of holding on grades specified in the 
requirements (20 percent or 30 percent). Par- 
ticular stress was placed on brake holding capa- 
bility on a 75 skid number surface. One com- 
menter requested that the same requirements 
apply to all vehicles, claiming it unrealistic for 
light vehicles to meet the 30 percent grade re- 
quirement while heavy vehicles onl}- had to meet 
a 20 percent requirement, and suggested use of a 
Swedish standard (16 percent grade, 110 pounds 
of foot brake force, 88 pounds of hand brake 
force). Ford requested allowance for use of a 
multistroke parking brake application. Ameri- 
can Motors Corporation requested reinstatement 
of existing Standard No. 105 requirements. GM 
and Chrysler objected to the requirement that 
the parking brake be of a "friction type" which 
they considered design restrictive, prohibiting 
other acceptable parking brake systems. 

The parking brake system test remains sub- 
stantially as adopted. The performance require- 
ments have been found feasible with present 
technology. A multistroke application is permis- 
sible, and limit of traction language has been 
added to the 30 percent grade requirement, to 
eliminate the irrelevant problem of tire slippage. 



The requirement for a friction-type parking 
brake is also retained. In a case of complete 
loss of service brake capability, a friction-type 
parking brake furnishes a residual stopping 
capability for a moving vehicle that is absent in 
a pawl-type system (such as the "park" position 
transmission stop). If the phrase "friction 
type" appears design restrictive of other types 
of parking brake systems that would provide 
equivalent capability, this agency will be recep- 
tive to suggestions for substitute language, with 
adequate supporting information. 

Wagner petitioned for deletion of the parking 
brake test with the vehicle at lightly loaded 
weight. This request is denied as the NHTSA 
believes that vehicles are frequently parked in a 
lightly loaded condition, and that a test should 
therefore be run at this vehicle weight. 

10. Indicator lamps. The standard has been 
amended so that indicator lamps may now be 
activated as a check of lamp function when the 
ignition is in the on position and the engine is 
not running, or in any position between on and 
start that is designated by the manufacturer as 
a check position. Ford petitioned that the brake 
fluid level indicator be deleted, but its request 
is denied as the NHTSA has determined that a 
warning should be provided in the event of slow 
leaks. Conversely, Mercedes-Benz of North 
America petitioned for deletion of the pressure 
differential warning, alleging that the fluid level 
indicator is sufficient. This, too, is denied, as the 
fluid level indicator will not indicate pressure 
failure until the fluid is at the level specified for 
a warning, an entirely different function. Sev- 
eral petitions asked that the 200-psi brake fluid 
pressure level be adopted (this had been proposed 
in Notice 1 for measurement at master or slave 
cylinder outlets), and these petitions have been 
granted. In response to several petitions, the 
illumination provided when an indicator lamp is 
activated may be flashing as well as steady- 
burning. 

11. Reservoirs. In the requirements for the 
master cylinder reservoir, clarifications have been 
provided in the determination of a fully worn, 
fully applied lining position. Reservoir labeling 
has been modified to require color contrasts of 
printed labels only, the contrast in lettering and 



PART 571; S 105 —PRE 13 



EfhcHvc Stptambar 1, 1975 



background on stamped or embossed labels 
deemed a sufficient contrast in those instances. 
GM asserted that the reservoir capacity require- 
ments were unnecessary in light of the require- 
ment for a fluid level indicator, and petitioned 
that the requirements be deleted. The petition 
is denied; the volume requirements are necessary 
to provide sufficient fluid for a full range of 
brake travel. 

12. Test conditions. The specified test load of 
50 to 725 pounds per cubic foot has been refined 
by assigning density distribution to various ve- 
hicle areas, for example 50 to 125 pounds per 
cubic foot in the seating area of all vehicles. 
Several manufacturers requested that the trans- 
mission selector control be in gear during all 
test decelerations, alleging that the neutral posi- 
tion is not representative of consumer usage. 
These requests are denied. Deceleration in gear 
by adding driveline drag masks the true effec- 
tiveness of the brake system. Comments were 
also directed to the prohibition against lockups, 
generally alleging inconsistency with Standard 
No. 121. These comments had merit, and the 
test condition has been amended to allow lockups 
during spike stops, partial failure stops and in- 
operative brake power or power assist unit stops. 
On the other hand, a request to allow more than 
one locked wheel is denied. Provision has been 
made for installation of a second thermocouple 
at the beginning of the test sequence if the lining 
wear is expected to reach a point causing the 
first thermocouple to contact the metal rubbing 
surface of a drum or rotor. Since the brake 
control forces have been modified to a uniform 
range of 15 to 150 pounds, except as otherwise 
specified, control forces have been added to the 
list of test conditions. 

13. Test procedures and seqv^n/ie. Most Amer- 
ican manufacturers and suppliers commented on 
the severity of the sequential procedure, with 
arguments of the following nature: The high 
speed effectiveness tests early in the sequence 
result in changes in lining characteristics which, 
in turn, affect the capability of the vehicles to 
comply with parking brake and partial systems 
requirements. Since no reburnish is allowed 
until after the first fade test, additional lining 
deterioration occurs as light load tests and fade 



tests are run. When final effectiveness tests are 
run, organic linings (normally used in today's 
vehicles) have deteriorated appreciably. This 
sequential testing, without reconditioning at in- 
tervals, results in brake torque balance changes 
as the test sequence progresses. To offset these 
changes and to enable a vehicle to go through 
compliance tests satisfactorily, many vehicles 
would have to be designed with an initial high 
gear brake capacity. This results in an unsafe 
early rear brake lockup, particularly at the initial 
light load test. As the sequence progresses, brake 
balance shifts toward a more reasonable balance, 
where all wheels approach lockup at or near 
same point. A brake balance which is designed 
initially for GVWR test conditions to meet 
Standard 105a requirements, would be dangerous 
to consumers for normal usage at 2 to 3 passenger 
loads due to rear wheel lockup and resultant 
uncontrollable skids. Recommendations by pe- 
titioners generally favored less testing at GVWR, 
reduced maximum t«st speeds, lessened fade re- 
quirements, and lessened final effectiveness re- 
quirements. The various changes would allow 
design of a brake system more suitable to normal 
consumer usage rather than the usage encountered 
in 105a tests. Ford recommended some changes 
in sequence but submitted a procedure incorporat- 
ing the 105a sequence with modified performance 
requirements. GM suggested a drastically re- 
vised sequence along with reduced performance 
requirements. Several petitioners recommended 
additional burnish stops and adjustments at 
several points, generally after each effectiveness 
series. Ford proposed a 200 stop additional 
burnish after the second fade test. 

In responding to petitions for reconsideration, 
the NHTSA has not modified the sequence of the 
test procedure. Recognizing the validity of 
many of (he comments, the NHTSA instead has 
adjusted all vehicle performance values to more 
closely correlate sequential testing with normal 
everyday driving performance. This has been 
accomplished by (1) reducing the high speed 
performance requirements, (2) eliminating high 
speed performance requirements at early sequence 
test points and retaining them only in the last 
effectiveness test, (3) allowing extra burnish 
stops for reconditioning of the lining materials, 
(4) modifying fade performance requirements, 



PART 571; S 105 —PRE 14 



(5) allowing a broader range of control force 
requirements while maintaining a maximum 
force limit of 150 pounds, (6) allowing extra 
adjustments of the brake system during the test 
sequence to provide more optimum brake per- 
formance, (7) modifying fade and wet-brake 
control force requirements to allow a broader 
range of forces without allowing a range that 
might produce severe over- or under-recovery. 
These modifications are intended to allow manu- 
facturers to design braking systems with a bal- 
ance that will provide satisfactory overall 
performance. 

At Ford's request, the general test procedure 
instructions have been modified to require lock- 
out of automatic adjusters prior to burnish and 
for the remainder of the test sequence. 

For the pretest instrumentation check, requests 
were received to specify a minimum number of 
instrumentation check stops or snubs, as well as 
the presently specified maximum. Such a speci- 
fication would, however, be meaningless. With 
the maximum number specified, each manufac- 



Effacliva: Stptombcr I, 1975 

turer knows precisely the "worst case" that his 
vehicles must be designed for, and should test his 
vehicles at or above that level. 

In consideration of the foregoing, 49 CFR 
§ 571.105a, Motor Vehicle Safety Standard No. 
105a, is revised to read as set forth below. 

Elective date: September 1, 1975. Because 
these amendments relate to a standard that is 
effective September 1, 1975, it has been deter- 
mined for good cause shown that an effective 
date later than 180 days after issuance is in the 
public interest. 

(Sec. 103, 119, Pub. L. 89-563, 80 Stat. 718, 
15 use 1392, 1407; delegation of authority at 
38 F.R. 12147). 

Issued on: May 11, 1973. 

James E. Wilson 
Associate Administrator 
Traffic Safety Programs 

38 F.R. 13017 
May 18, 1973 



PART 571; S 105— PRE 15-16 



Effective: September 1, 1975 



PREAMBLE TO AMENDMENT TO MOTOR VEHICLE SAFETY STANDARD NO. 105-75 

Hydraulic Brake Systems 
(Docket No. 70-27; Notice 10) 



This notice responds to further petitions for 
reconsideration of Motor Vehicle Safety Stand- 
ard No. 105a and amends the standard in certain 
minor respects effective September 1, 1975. 

Federal Motor Vehicle Safety Standard No. 
105a, 49 CFR 571. 105a, Hydraulic brake systems^ 
was published on September 2, 1972 (37 F.R. 
17970). Thereafter, pursuant to 49 CFR 553.35, 
petitions for reconsideration of the rule were 
received and, in response, a revised Standard 
No. 105a was published on May 18, 1973 (38 F.R. 
13017). Timely petitions for reconsideration of 
the revised rule were received from American 
Motors Corporation (AMC), Wagner Electric 
Corporation (Wagner), General Motors Cor- 
poration (GM), International Harvester Com- 
pany (Harvester), Japan Automobile Manufac- 
turers Association (JAMA), Ford Motor 
Company (Ford), Recreational Vehicle Institute 
(RVI), and Toyota Motor Sales, USA, Inc. 
(Toyota). This notice discusses the major issues 
raised and their resolution. The Administrator 
does not consider repetitious petitions and to the 
extern that these further petitions were repeti- 
tious of the initial ones {e.g. deletion of tests 
above 80 mi/h for heavy vehicles, modification of 
pedal forces, running tests in gear rather than 
in neutral), they have not been considered, pur- 
suant to NHTSA regulations (49 CFR 553.35 
(c)). 

GM petitioned for rulemaking that would re- 
scind Standard No. 105a on the grounds that the 
brake systems it has designed for the 1976 model 
year would have to undergo substantial changes 
in subsequent model years when it plans to intro- 
duce lighter vehicles with improved fuel con- 
sumption. This agency considers energy needs 
along with other factors relevant to its rulemak- 



ing actions. The information available to the 
NHTSA does not indicate, however, that Stand- 
ard No. 105a is incompatible with increased fuel 
mileage, or would add substantially to the weight 
of the vehicles covered. The NHTSA does not 
consider a cliange in a manufacturer's own de- 
sign plans to be a justification for discarding an 
important new set of requirements for which the 
world industry has been preparing for several 
years. The petition by GM to rescind the stand- 
ard is therefore denied. 

Effecth-e date : Harvester and RVI petitioned 
for a delayed eft'ective date for certain categories 
of vehicles. Harvester requested a one-year de- 
lay in the effective date for vehicles whose 
GVAVR exceeds 10,000 pounds, stating its doubt 
that acceptable antilock systems will be available 
to it by September 1, 1975, and that the advance 
hardware proposals from its brake system sup- 
pliers indicate that considerable design and de- 
velopment time is still needed. RVI wished an 
extension of 2 years for recreational vehicles 
built upon truck and multipurpose passenger 
vehicle chassis, alleging that time will be needed 
for testing and retooling after receijit of the first 
chassis or vehicle certified as conforming to the 
new braking standard. 

The NHTSA does not consider further exten- 
sion of the effective date to be in the public 
interest, and the petitions are denied. The broad 
outlines of the performance requirements have 
been known to industry since publication of the 
initial proposal in November, 1970, with its pro- 
posed effective date of September 1, 1972. Since 
publication of the new standard in September, 
1972, the effective date has been delayed one year 
to September 1, 1975. and considerable relief pro- 
vided for vehicles whose GVWR exceeds 10,000 
pounds. 



PART 571 ; S lOS^PRE l"! 



Effective: September 1, 1975 



Definitlcyns. In response to a petition by 
JAMA, a definition of "backup system" is 
adopted. Such a system is "a portion of a service 
brake system, such as a pump, that supplies 
energy in the event of a primary brake power 
source failure". 

Effective requirements. Clarifying words are 
added throughout in response to various requests. 
For example, the fourth effectiveness test now 
makes it clear that if the speed attainable in 2 
miles is 99 mi/h or greater, stops must be made 
from both 80 mi/h and a specified higher speed, 
and not from the higher speed alone. In response 
to GM's comments on inoperative brake power 
and power assist units (S5.1.3), a new S5.1.3.4 
has been adopted that allows brake power assist 
units to be tested under the optional procedure 
if the unit utilizes a backup system. 

The word "average" has been deleted from 
S5.1.4.2 (fade and recovery) which specified fade 
stops in excess of "an average deceleration" floor, 
at the request of Wagner, as the inclusion of the 
word was erroneous and does not reflect the test 
procedures of S7.1 1.2.1. 

The brake system indicator lamp requirements 
(S5.3.1) were the subject of numerous petitions, 
most of which have been granted. The NHTSA 
reiterates that the methods of pressure failure 
indication in S5.3.1(a) are alternative rather 
than inclusive. Harvester asked that S5.3.1(a) 
be amended to delete the qualification of pressure 
measurement at a slave cylinder outlet "if the 
master cylinder controls slave cylinders at a 
booster unit". It argues that with this design 
configuration it should be allowed to measure 
pressure at the master cylinder outlet. The 
NHTSA agrees that the original wording of 
S5.3.1(a) is design restrictive and that measure- 
ment at either the master or slave cylinder outlet 
is satisfactory for monitoring pressure, and the 
qualifying phrase is removed. S5.3.1 (a)(1) re- 
quires activation of the indicator upon activation 
of "a line pressure of not more than 200 psi". 
Ford requested an amendment to clarify that the 
intent is to specify a differential pressure between 
the operational and failed brake systems. The 
clarifying amendment has been made and the 
pressure differential increased to 225 psi to com- 
pensate for certain power-assisted imits. As a 



failure indicator GM prefers a switch that would 
activate the warning lamp when the brake pedal 
has been depressed past a certain point, rather 
than a lamp activated by fluid pressure failure. 

The petition is denied, as the NHTSA has 
determined that the brake pedal travel involved 
to activate the lamp would not provide an ade- 
quate warning. 

JAMA and Toyota asked for an amendment 
or interpretation of S5.3.2 that would allow the 
indicator lamp to remain activated when the ig- 
nition is returned to "on", after the engine is 
started. To allow the lamp to remain on after 
the engine is started might degrade the impor- 
tance of the check that the system is intended to 
indicate, and that the request is denied. JAMA 
also requested that if there is a separate parking 
brake indicator that it be labelled "Park", and 
this petition has been granted. 

GM requested that the volume requirements of 
master cylinder reservoirs on large trucks be 
reduced to one-third that required by the new 
standard. Since NHTSA has reduced the re- 
quirement in response to previous petitions, from 
150 per cent to 100 per cent of fluid displacement, 
it does not deem it in the interest of safety to 
reduce it further. GM's petition is denied. The 
agency wishes to clarify, however, that the vol- 
ume concerned is only that within the storage 
compartment, and does not include that fluid 
which may remain in pipes, hoses, and fittings. 
At Harvester's request, S5.4.2 is amended slightly 
to clarify that the minimum reservoir capacity 
is that of the total reservoir system rather than 
each reservoir compartment. 

S5.6, Brake system integrity, had been amended 
in May 1973 to specify that friction facing tear- 
out of the lining must "not exceed 10 percent of 
the lining on any frictional element" rather than 
"10 percent of the lining surface areas". GM 
requested reinstatement of the original require- 
ment. The request is denied. The language that 
was adopted in May 1973 clarified a previously 
existing ambiguity while providing a measure of 
relief that had been previously requested. 

Conditions. Ford interpreted the words "test 
load" in S6.1.1 as the load required to be added 
to bring a vehicle to its GV^VR. In some in- 
stances, if this added weight were distributed 



PART 571 ; S 105— PRE 18 



Effccllva: S*pt«cnbar I, 197S 



proportionally to GAWR the front GAWR 
would be exceeded. NHTSA intended that a 
vehicle be loaded at GV^VR so that its gross 
vehicle weight is distributed proportionally to 
its GAAVR, and S6.1 is amended appropriately. 
Ford, JA3IA, Toyota, and RVI petitioned for a 
change in the load material density specification 
of S6.2 to allow use of iron shot or bars in the 
passenger seating area, or in cargo areas of light 
and heavy trucks. The RVI request would allow 
use of lead shot in drawers, cupboards, and cabi- 
nets of recreational vehicles. In large part, these 
requests have been granted; maximum material 
densities have been increased from 125 to 450 
pounds per cubic foot in seating areas of passen- 
ger cars, and in cargo areas of vehicles with a 
GVAVR of 10,000 pounds or less. To allow the 
use of cast iron in the cargo areas of heavy trucks 
the minimum density has been lowered slightly 
from 450 to 400 pounds per cubic foot. The RVI 
request, however, is not adopted as this would 
permit too broad a range for testing and conse- 
quent difficulty of reproducing test results. It 
was to alleviate this problem that the original 
Standard No. 105a was amended on this point 
in May 1973. AMC and GM asked that the tire 
inflation pressure be that specified for the test 
weight, rather than for the GV\VR of the ve- 
hicle. In NHTSA's view, the time to reset tire 
pressures after allowing tires to cool would com- 
plicate and lengthen test procedures. There are 
only three tests run at the lightly loaded weight, 
and no data have been submitted to show that 
the tire pressure required causes a substantial 
increase in stopping distances. 

S6.10 allows only one uncontrolled wheel to 
lock at braking speeds above 10 mph on any 
given stop. GM suggested that this section al- 
lowed one wheel per axle to lock. GM's inter- 
pretation is incorrect, however; "one wheel" 
means one wheel on the vehicle. Ford wanted 
to reset thermocouples during brake inspections. 
This requested amendment is denied. Except for 
normal adjustment, inspections for thermocouple 
depths are not allowed once a test series has be- 
gun, in order that brake systems not be disturbed. 
The NHTSA may consider different depths for 
thermocouples in the future if data are obtained 
showing a need. 



Teat procedures. GM, JAMA, Toyota, and 
RVI petitioned that lockout of automatic brake 
adjusters be optional rather than required. On 
review the NHTSA has decided that there is no 
reason not to allow use of adjusters during test- 
ing. However, if a manufacturer locks out brake 
adjusters, this will now occur when linings are 
installed after the thermocouple installation; i.e. 
before the test series rather than before burnish. 
This is intended to save time in the test proce- 
dures. 

The service brake burnish procedure for heavy 
vehicles is being amended pursuant to a petition 
by GM, to be in accord with the procedure re- 
cently proposed for such vehicles in Standard 
No. 121. Minor clarifying amendments have 
been made at various places in the test proce- 
dures. Toyota asked whether S7.9.4 applied 
only to mechanical proportioning systems. This 
paragraph applies to any variable proportioning 
system whether mechanical, electrical, hydraulic 
or otherwise. It does not apply to a fixed me- 
chanical proportioning system. 

Figures and tables. Pursuant to a request 
from Ford, the dimensional specification of "l^^ 
inches" has been added to Lever A on Figure II. 
JAMA and Toyota want to consider a modified 
T lever as a "T" rather than as an "L" type. 
The NHTSA will consider this design a "T" 
type if the short side is no less than one-third 
the long side. JAMA and Toyota requested that 
the load point on the "L" type handle be revised 
to li/o inches from the handle end instead of 
from the center line. This request is denied, as 
the original requested dimension (30 mm) has 
been previously increased to li/^ inches (approxi- 
mately 37 mm) and no further change is deemed 
necessary. 

Harvester was the sole petitioner to request an 
increase in the stopping distances of Table II, 
asking that vehicles with a GVWR of 10,000 
pounds or less in the lightly loaded condition be 
afforded the same maximum stopping distance 
from 60 mph as required of similarly loaded 
vehicles under the same conditions in Standard 
No. 121. It also requested an increase in the 
fourth effectiveness stopping distance to give the 
same difference in deceleration at 80 mi/h as al- 
lowed by Standard No. 105 at 60 mi/h. Both 



PART 571; S 105— PRE 19 



Effective: September 1, 1975 



petitions are denied. Air-braked vehicles covered 
by Standard No. 121 include truck-tractors witli 
a high center of gravity and usually a higher 
front-to-rear weight distribution tlian light 
trucks, so that the lesser stopping distance in 
Standard No. 105 is justified. The test value of 
the fourth effectiveness test reflects previous 
modifications for requirements at 60 mi/h. The 
industry in general has not disclosed any prob- 
lem in comijlying witli the deceleration values 
from 80 mi/h. The correct stopping distance for 
heavy vehicles from 50 mi/h in the first, fourth, 
and spike effectiveness tests is 193 feet, not 183 
feet as previously published. 

GM, Toyota, and JAMA requested an increase 
in the deceleration values of Table III as an 
allowance for larger vehicles tested to optional 
brake power and assist unit procedures. This 
request is denied. The§e vehicles are presently 
required to meet only a 6.3 ft/s/s deceleration 
which is considered the minimum value accept- 
able. 

Finally, Harvester wanted an inclusive pedal 
force range of 15 to 150 pounds for all phases of 
compliance activity including baseline checks. 
The NHTSA considers a 150-pound pedal force 
too high for baseline tests at low speeds and 



relatively low decelerations, and the petition is 
denied. 

Although the NHTSA has on occasion used 
the subletter "a" to denote comprehensive revi- 
sion of existing standards effective at a future 
date, such standards will iienceforth be identified 
in terms of their effective dates. Thus "Standard 
No. 105a" becomes "Standard No. 105-75 (effec- 
tive September 1, 1975)". 

In consideration of the foregoing 49 CFR 
571.105a, Motor Vehicle Safety Standard 105a, 
hydraulic brake systems, is amended as follows: 

Effective date: September 1, 1975. Because 
these amendments relate to a standard that is 
effective September 1, 1975, it has been deter- 
mined for good cause shown that an effective 
date late than 1 year after issuance is in the 
public interest. 

(Sec. 103, 119, Pub. L. 89-563, 80 Stat. 718, 
15 U.S.C. 1392, 1407; delegation of authority at 
49 CFR 1.51.) 



Issued on February 14, 1974. 



James B. Gregory 
Administrator 
39 F.R. 6708 
February 22, 1974 



PART 571 ; S 105— PRE 20 



Effective: September 1, 1975 



PREAMBLE TO AMENDMENT TO MOTOR VEHICLE SAFETY STANDARD NO. 105-75 

Hydraulic Brake Systems 
(Docket No. 70-27; Notice 11) 



This notice responds to petitions for reconsid- 
eration of the amendments to 49 CFR 571.105- 
75, Motor Vehicle Safety Standard No. 105-75, 
published in the Federal Register on February 
22, 1974 (39 F.R. 6708). The standard is 
amended to defer for one year the requirements 
for a brake fluid level sensor for vehicles with a 
GVWR over 10,000 pounds, and for two years, 
a 60-pound maximum baseline pedal effort on 
vehicles with a GVWR over 15,000 pounds. 
Slightly increased stopping distances in the third 
effectiveness test are adopted for one year for 
certain heavy vehicles at lightly loaded vehicle 
weight. 

Timely petitions for reconsideration of the 
amendments were received fi-om Girling, Ltd., 
Wagner Electric Corporation (Wagner), Ford 
Motor Company (Ford), General Motors Cor- 
poration (GM), and Recreational Vehicle Insti- 
tute, Inc. (RVI). International Harvester 
Company (Harvester), subsequent to the time 
allowed for filing petitions for reconsideration, 
raised certain issues in writing to the Adminis- 
trator, and its presentation, in accordance with 
NHTSA regulations, has been considered as a 
petition for rulemaking. This notice discusses 
the major issues raised and their resolution. 

Effectii^e date: RVI again petitioned for a 
delayed effective date for recreational vehicles 
built upon truck and multipurpose passenger 
vehicles chassis, alleging that time will be needed 
by final-stage manufacturers for testing and re- 
tooling after receipt of the first chassis or vehicle 
manufactured after the effective date of Stand- 
ard No. 105-75. 

RVI's petition is found to be repetitious of 
arguments raised , previously, and accordingly, 
pursuant to NHTSA regulations (49 CFR 



55.3.35(c)), has not been granted. The denial of 
Notice 10 therefore stands, on the grounds set 
forth in Notice 10 of this docket. In brief, the 
NHTSA expects a manufacturer of incomi)lete 
vehicles to provide final-stage manufacturers, 
pursuant to 49 CFR 568, with information suf- 
ficient to indicate how the final-stage manufac- 
turer may achieve compliance with Standard No. 
10.5-75. Since the effective date of the standard 
is over a year away, there remains sufficient time 
for final-stage manufacturers to discuss with 
manufacturers of incomplete vehicles the kind 
of information that is to be provided, and to 
resolve such i)roblems as may appear. 

Harvester and Wagner have apprised the 
NHTSA of unexpected leadtime problems asso- 
ciated with the incorporation of brake fluid in- 
dicators into master cylinders of heavy vehicles. 
The agency has confirmed the seriousness of 
these problems, and has determined that they 
derive from factors substantially beyond the 
control of the affected vehicle manufacturers. 
It has accordingly concluded that a 1-year delay 
in the required date for introduction of fluid 
level sensors for vehicles whose GVWR exceeds 
10,000 pounds would be in the public interest. 

Harvester also requested a year's delay of the 
third effectiveness test requirements (S5.1.1.3). 
It stated that vehicles with 151 inches or less 
wheelbase and 8,000 pounds or greater GVWR 
will require anti-lock systems to meet the stop- 
ping distance requirements for lightly loaded 
vehicles, and that suitable anti-lock systems can- 
not be developed for 1976 model year production. 
The NHTSA does not consider that a year's 
delay of the third effectiveness test requirements 
is in the public interest. It finds, however, on 
the basis of the information before it that the 



PART 571 ; S 105— PRE 21 



Effective: September 1, 1975 



incorporation of anti-lock systems into this class 
of vehicles by the September 1, 1975, effective 
date is probably impracticable. The standard 
accordingly is being amended to permit, for a 
period of 1 year, somcwliat longer stopping dis- 
tance requirements for lightly loaded vehicles of 
8,000 pounds or more GVWR. The NHTSA 
finds these distances to be achievable without 
anti-lock systems, and that the change for the 
interim period is justifiable in terms of the costs 
and the safety benefits involved. As an example, 
the maximum stopping distance permissible from 
60 mph at lightly loaded vehicle weight is 
changed from 216 feet to 242 feet for vehicles 
with a GT\VR between 8,000 and 10,000 pounds. 

Efectiveness requirements. Clarifying words 
are again added to the effectiveness requirements 
and test procedures in response to various re- 
quests. Heretofore the performance require- 
ments for vehicles with inoperative brake power 
assist units and brake power units specified four 
stops at a deceleration figure, with the fifth and 
final stop specified in feet. This has apparently 
proved confusing, and the final stop will now 
be expressed in a manner consistent with the re- 
mainder of the performance requirements, as "an 
average deceleration of not lower than 7 fpsps". 
This value, however, applies only to passenger 
cars. Ford argued that the heavy truck stop- 
ping distance values are unrealistic, in the op- 
tional procedures provided by S5. 1.3.2 and 
S5.1.3.3 for inoperative brake power assist units 
and brake power units. It petitioned for less 
stringent values. The agency has considered 
that Ford's views have merit, and is amending 
the standard to require a final stop at an average 
deceleration of not lower than 6 fpsps. Table 
III has been amended to reflect this change. 

Two petitioners contested the pedal force 
baseline value range of 1.5 to 60 pounds for the 
fade and recovery and water recovery demon- 
strations. GM asked that the minimum be re- 
duced to 10 pounds, while Harvester requested 
an increase in the maximum to 88 pounds. GM 
submitted new test data to substantiate its re- 
quest and its petition is granted; but a floor of 
5 pounds is placed on the recovery minimum 
value. Harvester's petition is predicated on the 
results of "extensive tests" that show "that no 
vehicle over 15,000 lbs. GVIVR can be brought 



into compliance with this requirement for model 
year 1976." In recognition that even exerting 
its best efforts Harvester cannot comply by 
September 1, 1975, the NHTSA has detennined 
that a relaxation of this requirement for two 
years would be in the public interest. Therefore, 
Harvester's petition is granted, and between 
September 1, 1975, and September 1, 1977, the 
maximum baseline pedal effort will be 90 pounds 
with a restriction on fade recovery of 100 pounds 
maximum, and of 110 pounds on water recovery. 

With respect to the brake failure indicator 
lamp, Ford and Wagner requested clarification 
that the pressure failure condition is a rupture 
type, rather than one resulting from slow leaks. 
This request is granted, and S5.3.1(a) is amended 
to specify that the failure causing the lamp to 
operate is "A gross loss of pressure (such as 
caused by a rupture of a brake line) . . . ." Wag- 
ner also asked whether an automatic reset pres- 
sure failure valve would violate the standard. 
When there is a slow leak in the service brake 
system, the warning valve will shuttle, activating 
the indicator lamp, but the lamp will not remain 
activated when the pedal is released and then 
reapplied. The NHTSA intends the fluid level 
indicator to warn of fluid loss due to slow leaks, 
and the pressure differential indicator to warn 
of gross pressure loss. The failure of the lamps 
to remain activated by the valve does not violate 
Standard No. 105-75.' 

Some petitioners cited an apparent conflict in 
the previous denial of Toyota's petition to allow 
an indicator lamp to remain activated when the 
ignition is returned to "on" after the engine is 
started, and the fact that some systems do not 
instantly deactivate. NHTSA has previously 
noted in the notice of September 2, 1972 (37 
F.R. 17970), that no time interval is specified, 
and that instantaneous deactivation could not be 
required of continuous sensing units. The indi- 
cators considered acceptable to NHTSA are those 
that may remain activated for a limited time 
(such as 1 to 10 seconds) after the ignition is 
returned to "on". 

Finally, Wagner petitioned for reinstatement 
of the limiting phrase "in any reservoir compart- 
ment" in the requirement that an indicator lamp 
be activated whenever there is a drop in the level 
of brake fluid in a master cylinder reservoir to 



PART 571; S 105— PRE 22 



Effective: September 1, 1975 



less than one-fourth of fluid reservoir capacity. 
The phrase was deleted in the notice of February 
22, 1974, but it should have been retained to 
clarify that a low level in any reservoir com- 
partment must be indicated. Wagner's petition 
is granted. 

Test conditions. Ford requested an amend- 
ment of the test weight condition of S6.1 to 
clarify how, in the GVWR test condition, added 
weight is to be distributed, since even at lightly 
loaded weight on some vehicles the front axle 
load exceeds its proportional share of the GV^VR. 
The clarification is now provided by adding to 
S6.1.1 "However, if the weight on any axle at 
lightly loaded vehicle weight exceeds the axle's 
proportional share of the gross vehicle weight 
rating, the load required to reach GV^VR is 
placed so that the weight on that axle remains 
the same as at lightly loaded vehicle weight." 

Ford also asked that S6.2 Test loads be revised 
so that the manufacturer could designate the 
density of the test load selected, rather than to 
anticipate values that may be selected from 
within the i)rescribed range in the agency's com- 
pliance testing program. This petition is denied. 
Ford's suggestion would result in each manu- 
facturer setting its own unique performance 
requirements, and would not be appropriate for 
standards required by law to be uniform for the 
types of vehicles to which they apply. Each 
vehicle must comply with the requirements of 
the standard when loaded with materials of any 
density within the applicable ranges. This is 
made clear by the second sentence of S6., Test 
conditions: "Where a range of conditions is 
specified, the vehicle shall be capable of meeting 
the requirements at all points within the range." 

GM once again petitioned for an amendment 
of S6.4, Transmission selectm^ control^ to allow 
stopping of the test vehicle in gear rather than 
neutral. Since the agency, pursuant to 49 CFR 
§ 553.35, does not consider repetitious petitions, 
no action has been taken. 

Test procedures and sequence. S7. allows 
automatic adjusters to be locked out prior to 
burnish and for the remainder of the test se- 
quence. Girling has petitioned that lockout 



should only be in accordance with manufacturer's 
recommendations. NHTSA agrees and is amend- 
ing S7. accordingly. At the request of GM the 
agency has also amended S7. to outline a test 
procedure for conducting stops when the gear 
selector is required to be in the neutral position. 

Girling also asked that the postburnish brake 
adjustment test procedure (S7.4.1.2 and S7.4.2.2) 
be amended to make clear that these sections do 
not prohibit postburnish adjustment of man- 
ually adjustable brakes. Girling is correct, and 
appropriate amendments are made to reflect the 
agency's intent. 

Ford and Wagner both asked that the burnish 
procedure of S7.4.2.1.2 be amended in a manner 
consistent with Motor Vehicle Safety Standard 
No. 121, to allow brake applications at a point 
1.5 miles from the previous brake application for 
vehicles unable to attain any required speed in 
1 mile. The petition is granted, and the standard 
is amended accordingly. 

Finally, Ford suggested that the test proce- 
dure for first reburnish, S7.6, be changed to re- 
flect the optional procedure of S7.4.2.1.2, and 
this request has also been granted. 

Other minor amendments have been made to 
correct printing errors and for internal consist- 
ency. 

In consideration of the foregoing, 49 CFR 
571.105-75, Motor Vehicle Safety Standard No. 
105-75, is amended .... 

Effective date: September 1, 1975. Because 
these amendments relate to a standard that is 
effective September 1, 1975, it has been deter- 
mined for good cause shown that an effective 
date later than 1 year after issuance is in the 
public interest. 

(Sees. 103, 119, Pub. L. 89-563, 80 Stat. 718, 
15 U.S.C. 1392, 1407; delegation of authority at 
49 CFR 1.51.) 



Issued on July 9, 1974. 



James B. Gregory 
Administrator 

39 F.R. 25943 
July 15, 1974 



PART 571; S 105— PRE 23-24 



Effective: September 1, 1975 



PREAMBLE TO AMENDMENT TO MOTOR VEHICLE SAFETY STANDARD NO. 105-75 

Hydraulic Brake Systems 
(Docket No. 70-27; Notice 13) 



This notice amends Standard No. 105-75, Hy- 
draulic brake systems, 40 CFR 571.105-75, as it 
applies to passenger cars, in response to peti- 
tions for reconsideration of amendments pub- 
lished July 15, 1974 (39 F.R. 25943) (Notice 11). 
The amendments defer for one year the require- 
ment for a brake fluid level indicator and modify 
the permissible pedal force values used in re- 
covery stops. 

Manufacturers of hydraulic-braked motor ve- 
hicles responded to the Notice 11 amendments 
of the standard with petitions for reconsideration 
of specific technical changes in some performance 
requirements, and also with far-ranging requests 
for substantial modification, delay, or revocation 
of the standard. These broad requests are an- 
swered in a separate proposal to delay the effec- 
tive date of the standard for four months in the 
case of passenger cars, and indefinitely in the case 
of multipurpose passenger vehicles (MPV's), 
trucks, and buses. For this reason, only the spe- 
cific technical elements that necessarily affect 
passenger cars are addressed in this notice. 

Brake fluid level indicator. Chrysler Corpora- 
tion, Ford Motor Company, General Motors, and 
Wagner Electric Corporation responded to the 
1-year delay in fluid level indicator requirements 
for heavy vehicles by asserting that procurement 
and reliability problems also exist for lighter 
vehicle categories. The NHTSA contacted several 
manufacturers of brake fluid level indicators and 
discussed the availability and reliability of their 
products. It appeared that further field evalua- 
tion of available indicators could improve their 
reliability and that some delay should solve the 
availability problems which existed. At the Feb- 
ruary 11 public meeting, American Motors Cor- 
poration confirmed that availability problems 



still exist for brake fluid level indicators. Con- 
sequently, the NHTSA amends the standard to 
defer requirements for brake fluid level indicators 
until September 1, 1976. 

International Harvester requested clarification 
in the wording of S5.3.1(b), which appears to 
require a signal if the amount of brake fluid in 
a small, nearly full compartment of a split sys- 
tem reservoir does not equal one-quarter of the 
volume of the larger compartment. The NHTSA 
agrees that confusion may arise from the present 
wording, and, without changing the intended 
meaning of the requirement in any way, amends 
the wording as requested by Harvester. 

Ford requested a clarification of wording in 
S5.3.1(a), which presently calls for a signal when 
"any" one of several pressure losses is experienced. 
Ford correctly notes that the NHTSA use of 
"any" means that the vehicle or system must be 
capable of meeting the specified requirement upon 
the occurrence of every condition listed, and that, 
in this case, such was not intended. The NHTSA 
has corrected the wording to make clear that 
only one of the conditions (at the option of the 
manufacturer) must be indicated by the brake 
system indicator lamp. 

Maximum and minimum brake pedal force — 
recovery stops. Chrysler and the Japan Auto- 
mobile Manufacturers Association (JAMA) sup- 
ported the Notice 11 reduction of baseline pedal 
force limits to permit optimization of braking 
characteristics over the whole range of system 
operating conditions. Their petitions argued for 
an additional change to the minimum pedal 
effort in the first through fourth recovery stops 
to encourage optimal recovery characteristics. 
Specifically, Chrysler recommended that the 
present 15-pound limit (S6.1.13) on minimum 



PART 571; S 105— PRE 25 



EffecHva: Sapiembsr 1, 1975 



pedal force in the early recovery stops be re- 
placed by a formula tied to the average control 
force for the baseline check. To avoid over- 
sensitive brakes, a minimum pedal force of five 
pounds would be required. 

The NHTSA concludes that such a requirement 
would allow greater design freedom in optimizing 
brake recovery without sacrificing limits on brake 
sensitivity. Accordingly, the NHTSA reconsiders 
its action on minimum brake control force re- 
quirements, and amends the standard in response 
to JAMA and Chrysler. 

Chrysler also raised the issue of maximum al- 
lowable pedal force in the fifth stop of the water 
recovery requirements. Presently this pedal force 
can be a maximum of 90 pounds (60 pounds for 
average control force in the baseline check plus 
30 pounds) , but this formula requires lower pedal 
force on a vehicle with lower average baseline 
pedal force. Chrysler has considered changes in 
brake lining to lower the wet recovery stop values, 
but the modifications include major disadvantages 
such as increased brake imbalance, larger boosters, 
noise, and wear. The NHTSA finds that the 
formula can be revised to avoid penalizing good 
baseline performance, while maintaining a 90- 
pound maximum effort. Accordingly, S5. 1.2.5 
is amended to permit a 45-pound increase of pedal 
effort, as long as the maximum effort does not 
exceed 90 pounds. 

Other requirements of the standard. Wagner 
requested that the Notice 11 revisions of "in 
neutral" procedures be made consistent with other 
jjrovisions of the standard, or that they be re- 
placed with other procedures. The NHTSA finds 
the present procedure more reproducible than 
that suggested by Wagner and therefore denies 
this petition. Wagner correctly pointed out that 
the procedure to "exceed the test speed by approx- 
imately seven mph" may contradict the require- 
ment of testing at speeds only four mph lower 
than maximum attainable speeds (S5.1). Ac- 
cordingly, "four to eight mph" is substituted for 
"approximately seven mph" in S7. 



In a related area, JAMA requested that the 
test procedure for wet brake recovery stops be 
modified (S7.16.2). The NHTSA did not ad- 
dress these procedures in Notice 11, and does 
not find that this new subject matter is appro- 
priate for consideration at this time. The JAMA 
petition will be considered as a petition for rule- 
making which will be addressed in the near 
future. 

Bendix requested clarification of the Notice 8 
preamble discussion of "power assist" and 
"power" units. Bendix's question arose with re- 
gard to its "hydro-boost" unit, which is described 
as designed with a "push through" capability in 
both the "normal" and "failed power" operating 
conditions, and with an accumulator that permits 
low pedal effort for a limited number of brake 
applications after a power failure has occurred. 
The NHTSA concludes that, because the Bendix 
"hydro-boost" does not prevent the operator from 
braking the vehicle by an application of muscular 
force in the "failed power" condition, it qualifies 
as a brake power assist unit under the definitions 
of Standard No. 105-75. 

Several minor amendments have been made to 
correct a printing error in Table I as it appeared 
in Notice 8 (38 F.R. 13017, May 18, 1973) and 
for consistency in the use of abbreviations and 
terminology. 

In consideration of the foregoing. Standard 
No. 105-75 (49 CFR 571.105-75) is amended 

Effective date: September 1. 1975: Because the 
amendments relax a requirement and because the 
present effective date of the standard is Septem- 
ber 1, 1975, it is found for good cause shown 
that an effective date sooner than 180 days fol- 
lowing publication of the amendments in the 
Federal Register is in the public interest. 

(Sec. 103, 119. Pub. L. 89-563, 80 Stat. 718 
(15 U.S.C. 1392, 1407); delegation of authority 
at 49 CFR 1.51) 

Issued on March 6, 1975. 

Noel C. Bufe 
Acting Administrator 

40 F.R. 11584 
March 12, 1975 



PART 571 ; S 105— PRE 26 



EfFeclive: Septembar 1, 1975 



PREAMBLE TO AMENDMENT TO MOTOR VEHICLE SAFETY STANDARD NO. 105-75 



Hydraulic Brake Systems 
(Docket No. 70-27; Notice 14) 



This notice amends Standard No. 105-75, Hy- 
drauUc brake systems, 49 CFR 571.105-75, to 
make it applicable only to passenger cars equipped 
with hydraulic brake systems. This amendment 
has the effect of withdrawing the standard's ap- 
plicability to multipurpose passenger vehicles 
(MPV's), trucks, and buses equipped with hy- 
draulic brake systems. 

The National Highway Traffic Safety Admin- 
istration (NHTSA) proposed a 4-month delay of 
the standard as it applies to passenger cars and 
indefinite delay as it applies to other hydraulic- 
braked vehicles (40 FR 10483, March 6, 1975). 
Manufacturers responded to the proposed 4-month 
delay for passenger cars with objections to tech- 
nical features of the standard, the costs of mid- 
year changes, and the NHTSA's estimate of the 
standard's safety benefits. While consideration 
of these issues continues, a decision has been 
made to withdraw the standard's applicability to 
trucks, buses, and MPV's. 

The NHTSA proposed withdrawal of the 
standard because of uncertainty that the particu- 
lar performance levels established for trucks. 
MPV's, and buses by Standard No. 105-75 were 
justified in view of their costs. It is clear that 
truck braking is in many cases substantially 
poorer than passenger car braking, and that the 
generally longer stopping distances and the 
greater severity of truck accidents justify a safety 
standard for these vehicles. At the same time, 
the costs of meeting Standard No. 105-75 in all 
truck, bus, and MPV model lines are substantial 
and the NHTSA is not prepared to conclude that 
they are justified in view of achievable safety 
benefits. 



The Center for Auto Safety (CFAS) ques- 
tioned the NHTSA's right to propose withdrawal 
of a promulgated rule in response to manufac- 
turer cost objections without publication of the 
agency's evaluation of the submitted cost data. 
As authority, CFAS cites the newly-enacted cost 
information provisions of the National Traffic 
and Motor Vehicle Safety Act (15 U.S.C. § 1402). 

In this case manufacturers submitted costs for 
light- to meditim-duty trucks that ranged from 
$54 to $775 per unit (depending on model con- 
figuration) to attain compliance with the stand- 
ard. The NHTSA compared these figures with 
independently-gathered detailed cost and mark- 
up information and substantiated that the manu- 
facturer's estimates were accurate. This material 
has been formally compiled as required by the 
Act and has been made public in the docket (70- 
27; Notice 12). 

CFAS, the Consumers Union. Ms. Susan P. 
Baker of Johns Hopkins University, the Insur- 
ance Institute for Highway Safety, and the 
Permanente Medical Group stressed the import- 
ance of a brake standard for these vehicles. 
Tlie NHTSA agrees and intends to issue interim 
requirements for MPV's, trucks, and buses 
equipped with hydraulic brake systems. How- 
ever, the NHTSA concludes that the Standard 
105-75 requirements in their present form cannot 
be justified for trucks, buses, and MPV's on the 
basis of the data available at this time. 

In consideration of tlie foregoing. Standard 
No. 105-75 (49 CFR 571.105-75) is amended 

Effective date: September 1, 1975. Because 
the effective date of the standard for trucks, 
buses, and MPV's was less than 180 days after 
the date of publication of this amendment in the 



PART 571 ; S 105— PRE 27 



Effective: September 1, 1975 

Federal Register^ it is found for good cause Issued on April 25, 1975. 

shown that an effective date less than 180 days 

from the date of publication is in the public 

interest. Ja"^es B. Gregory 

(Sec. 103, 119, Pub. L. 89-563, 80 Stat. 718 (15 Administrator 

U.S.C. 1392, 1407); delegation of authority at 40 F.R 18411 

49 CFR 1.51). April 28, 1975 



PART 571 ; S lOo^PRE 28 



Effsctive: June 9, 1975 



PREAMBLE TO AMENDMENT TO MOTOR VEHICLE SAFETY STANDARD NO. 105-75 

Hydraulic Brake Systems 
(Docket No. 70-27; Notice 15) 



This notice amends Standard No. 105-75, Hy- 
draulic brake systems, 49 CFR 571.105-75, to de- 
lay its effective date four months from September 
1, 1975, to January 1, 1976, and to establish in- 
terim control force values for water recovery 
testing. This notice also amends the present hy- 
draulic brake system standard for passenger cars 
(Standard No. 105, Hydraulic brake systems, (49 
CFR 571.105)) to permit compliance with that 
standard or the new standard at the option of 
the manufacturer until January 1, 1976. 

As issued. Standard No. 105-75 applied to 
passenger cars, trucks, buses, and multipurpose 
passenger vehicles (MPV's) equipped with hy- 
draulic brake systems. Its scheduled effective 
date was September 1, 1975. Thirteen petitions 
for rulemaking to postpone or revoke the stand- 
ard were filed with the NHTSA earlier this year. 
Following a comprehensive evaluation of the 
petitions, the NHTSA proposed and made final 
an indefinite delay of the standard as it applied 
to trucks, buses,' and MPV's (40 F.R. 10483, 
March 6, 1975; 40 F.R. 18411, April 28, 1975). 

At the same time, the agency denied petitions 
for substantia] postponement or revocation of the 
standard as it applies to passenger cars, having 
considered the cost of compliance for those ve- 
hicles, and having determined that significant 
safety benefit will derive from better stopping 
performance, stability, and pedal force levels (40 
F.R. 10483, March 6, 1975). A discussion of the 
potential benefits accompanied that decision. An 
economic evaluation of the impact of the standard 
will be available in the public docket. The only 
revisions of tlie standard proposed by the NHTSA 
were an interim pedal force value and a 4-month 
delay of effective date, to permit some flexibility 
in new model introduction dates where technical 



changes or isolated compliance problems had not 
been resolved. 

Manufacturer comments on the proposal were 
generally unresponsive to the proposed delay of 
four months and the interim pedal force value of 
110 pounds in wet recovery stops. The Vehicle 
Equipment Safety Commission considered the 
proposed pedal force values to be overgenerous. 
Chrysler Corporation indicated its support for 
the 4-month delay and interim value but em- 
phasized other arguments in its submission. Gen- 
eral Motors requested that the pedal force value 
be made permanent. It appears that manufac- 
turers support the short delay and pedal force 
modification to simplify introduction of the 1976 
models. Accordingly, the standard is modified 
as proposed, to establish an amended effective 
date of January 1, 1976, and a pedal force in- 
crease of 60 pounds up to a total of 110 pounds 
(in S5.1.5.2) until September 1, 1976. 

The majority of comments restated manufac- 
turer positions on the issue of substantial delay 
or revocation of the standard for passenger cars. 
Tlie NHTSA has already considered this issue 
and, as noted above, concluded that the benefits 
of improved stopping performance, stability, and 
pedal force values outweigh the costs of imple- 
mentation. Manufacturers submitted no new data 
that would justify a reversal of NHTSA's earlier 
decision. 

Although the NHTSA limited its proposal to 
a choice between the effective dates of September 
1. 1975, and January 1, 1976. several manufac- 
turers compared the cost savings of a short delay 
to January 1. 1976, with a substantially longer 
delay to September 1, 1976. Actually, the Jan- 
uary 1 date was proposed in order to ease the 
introduction of new models after September 1, 



PART 571 ; S 105— PRE 29 



EflFective: June 9, 1975 



1975, and was not proposed as a means of re- 
ducing costs. The proposal was largelj' in re- 
si^onse to manufacturers' comments that some 
1976 models would be introduced substantially 
later than normal so that 1975 model production 
might be extended beyond September 1, 1975. 
The NHTSA believes that the three years of lead- 
time since promulgation of Standard No. 105-75 
have been sufficient to permit the design and test- 
ing of complying brake systems in nearly all 
cases. With the 4-month transitional period, a 
manufacturer will be free to introduce the new 
brake systems along with its new model introduc- 
tion, as dictated by the economic situation of the 
automotive industry. 

Ford and Chrysler suggested that the standard 
could be improved by reduced loading during 
brake fade testing. These companies argue that 
present-day brake balance must be modified to 
meet the brake-fade and fourth effectiveness test 
of Standard No. 105-75 and that the new balance 
is not optimum. Agency testing demonstrates 
that many present-day vehicles can in fact meet 
the requirements as their brakes are balanced 
and suggests that major departures from current 
brake balance design will generally not be re- 



quired to comply with fade requirements under 
the present test conditions. The NHTSA accord- 
ingly concludes that the presently-specified load- 
ing does not result in characteristics whicli would 
justify delay of the standard and the consequent 
loss of benefits during the period of delay. 

In consideration of the foregoing, Standard 
No. 105-75 (49 CFR 571.105-75) is amended 

Effective date: The date on which Standard 
No. 105-75 becomes mandatory for all passenger 
cars is January 1, 1976. However, the effective 
date of the amendments to both Standard No. 
105-75 and Standard No. 105 is June 9, 1975, and 
passenger cars manufactured between that date 
and January 1, 1976, may conform to either 
standard at the discretion of the manufacturer. 

(Sec. 103, 119, Pub. L. 89-563, 80 Stat. 718 (15 
U.S.C. 1392, 1407); delegation of authority at 
49 CFR 1.51.) 

Issued on June 5, 1975. 

James B. Gregory 
Administrator 

40 F.R. 24525 
June 9, 1975 



PART 571 ; S 105— PRE 30 



Effective: September 17, 1975 



PREAMBLE TO AMENDMENT TO MOTOR VEHICLE SAFETY STANDARD NO. 105-75 

Hydraulic Brake Systems 
(Docket No. 70-27; Notice 16) 



This notice responds to three petitions for 
reconsideration of recent amendments of Stand- 
ard No. 105-75, Hydraulic brake systems, 49 CFR 
571.105-75 (40 F.R. 11584, March 12, 1975) 
(Notice 13). The petitions requested clarifica- 
tion of new language that specifies minimum 
control force application values (S5.1.4.3(a) (2) 
and S5.1.5.2(a) (2) ) and objected to the NHTSA 
decision to defer for 1 year the requirement for 
a brake fluid level indicator in passenger cars. 

Wagner Electric Corporation requested clari- 
fication of the description of minimum permis- 
sible control force application value, Avhich reads, 
"A minimum of 10 pounds or 40 percent (which- 
ever is greater) less than the average control 
force for the baseline check (but in no case less 
than 5 pounds)." Starting with a baseline 
value, the manufacturer must utilize the lower 
of two values which result when diilerent 
amounts are subtracted from the baseline value. 
Because there is some ambiguity in the language 
used to describe these calculations, the NHTSA 
hereby revises the language to improve its clar- 
ity. The new wording in no way modifies the 
meaning of S5.1.4.3(a) (2) and S5.1.5.2(a) (2). 

Ford Motor Company, Wagner, and Mei'cedes- 
Benz requested reconsideration of the decision to 
defer for 1 year the requirement of S5. 3.1(b) 
that specifies a brake fluid level indicator. Ford 
and Wagner requested that the indicator be 
permanently deleted from the requirements in 
view of expense and reliability problems, claim- 
ing that its function is adequately served by the 
pressure differential warning that is also re- 
quired by the standard. 

The fluid level indicator detects and signals a 
loss of fluid from the system, whether the loss is 
swift or gradual. In the event of such a dan- 



gerous condition, the vehicle operator is warned 
early that braking function will be lost in the 
future. Unlike the pressure differential indi- 
cator, the fluid level indicator warns the oper- 
ator before one subsystem is effectively depleted 
of all fluid, and permits a repair to be under- 
taken before braking is lost. The indicator 
would also signal leakage at a wheel cylinder 
which could contaminate brake linings and 
create a side-to-side imbalance in braking. 

At the same time, the petitions raise questions 
about the "reliability, availability, and cost of 
these devices that cannot be answered without 
further data. The NHTSA is in the process of 
gathering these data, and for this reason is un- 
able to respond to these two petitions within the 
120-day period established for actions on peti- 
tions for reconsideration. The NHTSA antici- 
pates publication of its response no later than 
October 31, 1975. 

Mercedes-Benz argued that the 1-year deferral 
of the brake fluid level indicator discriminated 
against those manufacturers who presently pro- 
vide such a device to meet the present Standard 
No. 105 (49 CFR 571.105). As interpreted, 
Standard No. 105 specifies a pressure differential 
indicator (used by most manufacturers) or a 
fluid level indicator (used by Mercedes) to signal 
a complete hydraulic-type failure of a partial 
system. Mercedes asked that the new standard 
be modified to continue this manufacturer option 
until both systems are required, reasoning that 
either system provides an equal safety benefit. 

As noted in the earlier discussion, a review of 
the benefits found in one warning indicator that 
are not found in the other demonstrates that 
there are separate and significant benefits in each 
warning. The new hydraulic brake standard 



PART 571 ; S 105— PRE 31 



fffeclive: September 17, 1975 



specifies botli w.arnings for tliis reason. The 
fluid level indicator was deferred only because 
of unresolved reliability and availability issues. 
The pressure difl'erential indicator is a proven 
and available device which can be incorporated 
in vehicles at reasonable cost. While the NHTSA 
does not wish to encourage removal of Mercedes' 
fluid level indicator, it has decided that all pas- 
senger cars should be equipped with the pressure 
differential indicatoi. For these reasons, Mer- 
cedes" petition is denied. 

In an area unrelated to the rulemaking which 
underlies this response to petitions for reconsid- 
eration. Toyota ;\Iotor Sales, Inc., has requested 
confirmation that S5.3.2 of the standard requires 
a check of the brake system indicator lamp func- 
tion only wlien the transmission shift lever is in 
the "P" (park) or "N" (neutral) position (in 
the case of vehicles with automatic transmis- 
sion). The literal wording of S5.3.2 requires a 
check of lamp function without regard to the 
position of the transmission shift lever, whenever 
the ignition switch is turned to the "on" position 
when the engine is not running, or when the 
ignition switch is in a position between "on" and 
"start" that is designated by the manufacturer 
as a check position. In the case of vehicles with 
an automatic transmission, however, this word- 
ing does not reflect the NHTSA's intent with 



respect to the check function. To properly re- 
flect this intent, the language of S5.3.2 is hereby 
modified in accordance with Toyota's request. 
This is an interpretative ruling, adding no addi- 
tional burden on any person, concerning which 
the XHTSA finds that notice and opportunity 
for comment are unnecessary, under provisions 
of the Administrative Procedures Act (5 U.S.C. 
§ 553(b) (3) (A)). 

In a separate area, the date of September 1, 
1975, appearing in S7.4.2.1 of the standard is 
changed to January 1, 1976, to conform to the 
standard's new efl'ective date. 

In consideration of the foregoing. Standard 
No. 105-75 (49 CFK 571.105-75) is amended. . . . 

Effectwc date: September 17, 1975. Because 
this amendment relieves a restriction and im- 
poses no additional burden on any person, it is 
found for good cause shown that an immediate 
eifective date is in the public interest. 

(Sec. 103, 119 Pub. L. 89-563, 80 Stat. 718 
(15 U.S.C. 1392, 1407); delegation of authority 
at 49 CFR 1.51.) 

Issued on September 11, 1975. 

James B. Gregory 
Administrator 

40 F.R. 42872 
September 17, 1975 



PART 571 ; S 105— PRE 32 



Eifaetive: October 10, 1975 



PREAMBLE TO AMENDMENT TO MOTOR VEHICLE SAFETY STANDARD NO. 105-75 

Hydraulic Brake Systems 
(Docket No. 75-11; Notice 2) 



This notice amends Standard No. 105-75, 
Hydraulic Brake Systems, 49 CFR 571.105-75, 
to permit the manufacture of hydraulic-braked 
vehicles without split service brake systems as 
long as they are capable of meeting additional 
stopping requirements in the event of failure in 
the service brake system. A proposal of this 
modification was published May 12, 1975, (40 FR 
20641), in response to petitions from Citroen 
Automobile Company, Maserati, S.P.A., and 
Volkswagen of America, Inc. 

The three vehicle manufacturers requested 
modifications of Standard No. 105-75 (eifective 
January 1, 1976) because its present requirement 
for a split service brake system (S5.1) would 
prevent the development and sale of vehicles 
utilizing a central hydraulic system with a single 
pump. The split system has two or more sepa- 
rate subsystems, each operating indefinitely in 
the event of a failure in another subsystem, and 
is required as a safety measure to ensure that at 
least one-half of the braking system will remain 
operational if any single failure occurs. The 
central hydraulic system used by Citroen em- 
ploys a single pump to supply power to both 
fi-ont brakes and rear brakes. The petitions sug- 
gested and the NHTSA tentatively agreed that 
this type of central hydraulic system, which offers 
a limited number of stops upon a single failure, 
provides warning and reserve braking capabilities 
equivalent in safety to a split system. The peti- 
tioners asserted that the danger of operating in- 
definitely on one-half of a split system is as great 
as that of operating a central hydraulic system 
beyond its reserve capability. 

The responses to the proposal (including 
approximately 30 endorsements from owners of 
Citroen vehicles which employ the central hy- 



draulic system) generally supported the amend- 
ment to provide additional design flexibility in 
meeting Standard No. 105-75. Citroen, which 
intends to import passenger cars with central 
hydraulic systems, supported the proposal with 
one exception. The company pointed out that 
the special warning system specified in the pro- 
posal to accompany the central hydraulic system 
was technically unfeasible and conflicted with 
the existing requirements for warning systems 
in vehicles equipped with brake power units 
(S5.3.1). The same problem was raised by 
Clayton Dewandre Company Limited, a manu- 
facturer of brake systems for trucks, and Volks- 
wagen of America. Essentially, central hy- 
draulic systems are designed to operate within 
a pressure range, with intermittent pump opera- 
tion to restore the system accumulators to the 
higher pressure of the ranges as energy is used 
in braking or other hydraulic systems. A pres- 
sure sensor would be unable to distinguish the 
type of pressure drop experienced in this normal 
operation from that resulting from a rupture or 
leakage-type failure. Only after the pressure 
dropped below the pump "cut-in" pressure could 
the sensor experience an abnormal pressure level 
signifying system failure. 

The proposal, in contrast, would have required 
a warning as soon as any leakage or rupture 
occurs, before the abnormal pressure drop would 
be sensed. To revise the requirement in practical 
terms, the NHTSA amends the standard to 
eliminate the conflict between the proposed re- 
quirement and the existing requirement of 
S5.3.1(a)(4) for a warning when the supply 
pressure in a brake power unit drops to some 
level not less than one-half of the normal system 
pressure. 



PAET 571; S 105-75— PRE 33 



EfFecllve: October 10, 1975 

The amendment is placed in the same section 
of the standard as other requirements for warn- 
ing systems (S5.3) to improve the coherence of 
the entire standard and to clarify that the pres- 
sure warning required on central hydraulic sys- 
tems is not redundant or in conflict with the 
warnings called for in S5.3.1(a). 

For the same reason, the proposed requirement 
for additional stopping capability in central hy- 
draulic systems is placed in the same section as 
the requirement for partial failure system per- 
formance of split service brake systems (S5.1.2). 
Also, the partial failure test procedures for cen- 
tral hydraulic systems have been consolidated 
into the test procedures for split service brake 
systems in S7.9.1. 

Citroen, Volkswagen, and Clayton Dewandre 
stressed that the delay of warning signal neces- 
sitates a more fundamental modification of the 
proposed requirement for additional stopping 
capabilities. The proposal would have specified 
that the warning signal be activated as soon as 
the failure occurred, followed by a back-up ca- 
pability of 10 stops from 60 mph. Now that the 
signal has been specified as occurring somewhat 
after the failure (when abnormal pressure loss 
can be sensed), the 10-stop capability must be 
required subsequent to activation of the signal so 
that braking capability is available to the driver 
for a reasonable time after he has been warned 
that a malfunction has occurred. Citroen, the 
only manufacturer that expects to manufacture 
vehicles subject to these requirements at this time, 
states that its system is entirely capable of pro- 
viding 10-stops from 60 mph after the warning 
system activates. For this reason, the NHTSA 
considers it appropriate to amend the warning 
system requirement so that the 10-stop capability 
is available following activation of the signal. 

The NHTSA also proposed a clarification of 
the test procedures for brake power unit failure 
(S7.10.2(b)). No comments addressed this mat- 
ter, and the proposed change expanded slightly, 
is made final by this notice. 

Citroen suggested that a brake fluid level in- 
dicator be specified as an additional safety system 
on central hydraulic systems, noting that such an 
indicator will become a requirement for vehicles 
with master cylinder reservoirs (as of September 



1, 1976). Wagner Electric Corporation recom- 
mended that a "system energy monitoring device" 
be specified so that volume as well as pressure 
would be monitored, arguing that a pressure in- 
dicator alone will not indicate a failure of the 
charging device in an accumulator. Clayton 
Dewandre suggested that if a split service brake 
system is no longer required, then the brake sys- 
tem should be better protected against failures 
of non-brake systems (suspension, power steer- 
ing) that are connected to the brake system. 

The NHTSA considers each of these sugges- 
tions to have possible merit and contemplates a 
new proposal to treat these issues and provide 
for full opportunity for comment by interested 
persons. At this time, however, it is considered 
necessary to implement the amendments that will 
permit production of vehicles without split service 
brake systems under Standard No. 105-75. 

Both Wagner Electric and General Motors 
questioned the part of the preamble to the pro- 
posal that stated, "The [Citroen] response indi- 
cates that the Citroen system is not responsible 
for a greater percentage of accidents than a con- 
ventional system." Both companies felt that the 
submitted information did not form a statistically 
adequate basis for that conclusion. The NHTSA 
agrees. The statement in question was only in- 
tended to report Citroen's evaluation of the ma- 
terial it submitted in support of its petition, and 
not to present a conclusion of the NHTSA. 

In consideration of the foregoing. Standard 
No. 105-75 (49 CFR 571.105-75) is amended 

Effective date: October 10, 1975. Because these 
amendments have the effect of permitting actions 
that previously were prohibited, it is found for 
good cause shown that an effective date sooner 
than 30 days following publication in the Federal 
Register is in the public interest. 

(Sec. 103, 119, Pub. L. 89-563, 80 Stat. 718 (15 
XJ.S.C. 1392, 1407) ; delegations of authority at 
49 CFR 1.51). 

Issued on Oct. 3, 1975. 

Gene G. Mannella 
Acting Administrator 

40 F.R. 47789 
October 10, 1975 



PAET 571; S 105-75— PRE 34 



Effective: Jqnuary 6, 1976 



PREAMBLE TO AMENDMENT TO MOTOR VEHICLE SAFETY STANDARD NO. 105-75 

Hydraulic Brake Systems 
(Docket No. 75-27; Notice 2) 



This notice amends Standard No. 105-75, 
Hydraulic Brake Systems, 49 CFR 571.105-75, 
to revise the parking brake test procedure 
(S7.7). In addition, this notice amends Subpart 
B of Part 575, Consumer Information, 49 CFR 
§ 575.101, by replacing the present test proce- 
dures in that section for passenger car testing 
with equivalent procedures from Standard No. 
105-75. 

The NHTSA proposed a modification of the 
parking brake test procedures in Standard No. 
105-75 to permit a reapplication of the parking 
brake if the first application of the brake failed 
to hold the vehicle stationary on the test incline. 
Toyo Kogyo requested the modification as repre- 
sentative of normal driver action (in cases where 
the application appears to be insulBcient to hold 
the vehicle), justifying the change as necessary 
to permit new vehicle components to stretch or 
"set" during the initial application as occurs in 
any vehicle delivered to a purchaser. The 
NHTSA agreed that reapplication would be a 
reasonable test procedure and proposed a revi- 
sion of S7.7. 

Comments were received from Toyo Kogyo, 
General Motors, American Motors Corporation, 
and Chrysler Corporation in support of the 
change. No comments were received that ob- 
jected to the proposal. The standard is amended 
accordingly. 

The NHTSA also proposed that the consumer 
information item requiring publication of the 
stopping ability of passenger cars and motor- 
cycles (49 CFR §757.101) be modified for pas- 
senger cars so that test data developed under 
Standard No. 105-75 could be the basis for the 
required consumer information. The existing 
test procedures of the consumer information item 



would be replaced by Standard No. 105-75 test 
procedures, and a transition period until Janu- 
ary 1, 1977, would be provided to allow manu- 
facturers latitude in adopting the new procedures. 

The Motor Vehicle Manufacturers Association 
(MVMA), Chrysler Corporation, American 
Motors Corporation, Ford Motor Company, and 
General Motors Corporation supported the modi- 
fications. The MVMA and Ford pointed out an 
inadvertent omission in the proposal of a re- 
quired change in the present loading specification 
(maximum loaded vehicle weight) to the Stand- 
ard No. 105-75 loading specification (gross 
vehicle weight rating (GVWR)). No comments 
opposed the modification, and the consumer in- 
formation item is therefore amended as proposed, 
with the additional modification noted by the 
MVMA and Ford. The transition period for 
use of either loading specification conforms to 
the transition period for use of either test pro- 
cedure (until January 1, 1977). The MVMA 
asked for a June 1, 1977, date for transition to 
the new loading specification but did not explain 
the need for more time. The NHTSA will con- 
sider any data on this subject submitted by the 
MVMA. 

With regard to test loading, Chrysler Cor- 
poration repeated a request for revision of the 
loading conditions of Standard No. 105-75. The 
request was earlier submitted improperly as a 
petition for reconsideration of an NHTSA action 
which did not deal with test loading (40 FR 
24525, June 9, 1975). Section 553.35 of NHTSA 
regulations (49 CFR 553.35) allows petitions 
for reconsideration of rules issued by the 
NHTSA, but in this case no rule was issued on 
test loading that could form the basis for recon- 
sideration. The NHTSA discussed Chrysler's 



PART 571; S 105-75— PRE 35 



Effective: January 6, 1976 

request at a meeting with Chrysler officials on 
August 21, 1975. Based on the limited infor- 
mation presented by Chrysler at that meeting, 
the NHTSA has concluded that a reduction in 
test weight would not be justified. At the meet- 
ing it was agreed that Chrysler would submit 
any additional data it had in support of the re- 
quest. To date no data have been received, and 
the NHTSA cannot meaningfully reconsider 
Chrysler's request without further data. 

The NHTSA also proposed modification of 
the means for establishing the skid number of 
the surface on which stopping distance tests are 
conducted in Standard No. 105-75, Standard No. 
121, Air Brake Systems, Standard No. 122, Motor- 
cycle Brake System, and the Consumer Infor- 
mation Item on brake performance. Comments 
received were not in agreement on how to accom- 
plish the transition from the former ASTM 
method to the new one. The skid number pro- 
posal will therefore be treated separately at a 
later date so that its resolution will not delay 



this amendment of the parking brake and con- 
sumer information item test procedures. 

In consideration of the foregoing, amendments 
are made in Chapter V of Title 49, Code of 
Federal Regulations. . . . 

Effective date : January 6, 1976. Because these 
amendments, to the extent that they impose new 
substantive requirements, are made optional for 
an interim period, and because manufacturers 
must plan future testing based on the test pro- 
cedures as they exist in the present standard, 
it is foimd for good cause shown that an im- 
mediate effective date is in the public interest. 

(Sec. 103, 119 Pub. L. 89-563, 80 Stat. 718 (15 
U.S.C. 1392, 1407) ; delegation of authority at 
49 CFR 1.51). 

Issued on December 31, 1975. 

James B. Gregory 
Administrator 
41 F.R. 1066 
January 6, 1976 



PART 571; S 105-75— PRE 36 



Effective: October 12, 1976 



PREAMBLE TO AMENDMENT TO MOTOR VEHICLE SAFETY STANDARD NO. 105-75 

Hydraulic Brake Systems 
(Docket No. 75-7; Notice 2) 



This notice amends Standard No. 105-75, 
Hydraulic Brake Systems, 49 CFR 571.105-75, to 
extend its applicability to school buses and to 
establish performance levels for tliis vehicle cate- 
gory. 

The NHTSA proposed applicability of the 
hydraulic brake standard to school buses (40 FR 
18469, April 28, 1975) in satisfaction of the man- 
date of the Motor Vehicle and Schoolbus Safety 
Amendments of 1974 (Pub. L. 93-492) to issue 
safety standards for school bus operating sys- 
tems (15 U.S.C. §1392(i)(l)(A)). The Act 
established a strict schedule for promulgation 
of the standards, requiring their effectiveness 9 
months following promulgation. With a view 
to this limited leadtime, the NHTSA proposed 
performance levels based on Society of Auto- 
motive Engineers (SAE) recommended practices 
that reflect the better existing school bus designs. 
Permissible pedal force values and fade and re- 
covery performance were proposed at somewhat 
more stringent levels than the SAE practice, in 
view of the "stop-and-go" duty cycle of school 
buses, and the high incidence of women as school 
bus operators. 

Conmienters generally supported extension of 
the hydraulic brake standard to school buses. 
The American Mutual Insurance Alliance sup- 
ported the standard as proposed. The California 
Highway Safety Foundation and Action for 
Child Transportation Safety (ACTS) advocated 
early implementation of requirements for all 
hydraulic-braked trucks, buses and multipurpose 
passenger vehicles to improve their braking com- 
patibility with school buses and passenger cars. 
The California Department of Highway Patrol 
(CHP) expressed concern that any bus could 



be converted into a school bus after sale, and 
that all buses should therefore be required to 
meet minimum braking requirements. The 
NHTSA is presently preparing rulemaking for 
hydraulic-braked trucks, buses, and MPV's, and 
these comments are being taken into considera- 
tion. In view of the Congressional mandate for 
swift implementation of school bus standards, 
however, tliis rulemaking is being made final 
largely as it was proposed. 

The NHTSA proposed a level of service brake 
system performance generally based on SAE 
values, both for school buses of 10,000 pounds 
gross vehicle weight rating (GVWR) or less, and 
for school buses with a GVWR or more than 
10,000 pounds. Wagner Electric Corporation, 
Chrysler Corporation, International Harvester 
Co., and Ford Motor Company asked for relaxa- 
tion of the requirements, while the Vehicle 
Equipment Safety Commission (VESC) and 
ACTS requested more stringent requirements. 
General Motors supported the requirements for 
buses with a GVWR of 10,000 pounds or less. 

The first effectiveness test (S5.1.1.1) measures 
the stopping ability of the service brake system 
as it is delivered to the user before it has been 
burnished (broken in) through use. Wagner 
argued that this test is umiecessary and there- 
fore wasteful because the stringency of later tests 
assures the adequacy of the "green" braking com- 
ponents to stop the vehicle. The company cited 
variables in the unconditioned components that 
make it ". . . unrealistic to assume that exact 
brake performance can be predicted or that test 
results can be repeated without the thermal and 
mechanical conditioning of these surfaces." 



PART 571; S 105-75— PRE 37 



EfFecHve: October 12, 1976 



It is the NHTSA's intent in the first effective- 
ness test to assure a safe vehicle in the hands 
of the user from the moment of delivery. The 
same variables cited by Wagner that make pre- 
diction of test results difficult could also make 
performance in the hands of the user unpre- 
dictable, unless the design is carefully controlled. 
The NHTSA concludes that the first effective- 
ness requirement is a reasonable method of ensur- 
ing adequate new-vehicle performance, and denies 
Wagner's request to delete this requirement. 

Chrysler and Ford recommended increasing 
the first effectiveness stopping distances at 30 
mph for school buses with a GVWHR of 10,000 
pounds or less. Both argued that vehicles take 
significantly longer to stop in an unbumished 
condition and therefore the required stopping 
distance for first effectiveness should be longer 
than the second effectiveness requirement. The 
NHTSA established the unbumished stopping 
distance requirements based on tests of vehicles 
by NHTSA contractors and its Safety Research 
Laboratory. The NHTSA has reexamined its 
test results in view of manufacturer comments, 
and has determined that the complying distances 
recorded were not generated in all cases at the 
"worst case" weight at which a vehicle could 
be tested. For this reason, and because of the 
variability noted above, the NHTSA has in- 
creased the first effectiveness stopping distances 
for school buses of 10,000 pounds GVWE or less 
to 69 feet. This change represents a 1 fpsps 
decrease in average deceleration rate from the 
second effectiveness value, as is the case for pas- 
senger cars. 

In the case of vehicles with a GVWTl of more 
than 10,000 pounds, Wagner, Chrysler, and 
International Harvester requested longer stop- 
ping distances at 30 mph. The VESC and ACTS 
requested the same stopping distances for heavy 
school buses as for lighter ones. The NHTSA 
proposed more stringent low-speed stopping re- 
quirements than the SAE values to remain con- 
sistent with existing requirements of the National 
Conference on School Transportation, the State 
of California, and the Bureau of Motor Carrier 
Safety. International Harvester pointed out 
that, while the distances are comparable, the re- 
quirements are in fact more stringent because of 



the "no lockup" requirement and the limits on 
pedal control force in Standard No. 105-75. In 
view of these variations from existing 30-mph 
stopping distance requirements, and the less effec- 
tive braking encountered prior to burnish, the 
first effectiveness stopping distance at 30 mph 
is increased from 81 feet to 88 feet. In terms 
of deceleration rate, this 7-foot increase is com- 
parable to the 4-foot increase for light school 
buses. Stopping distance requirements other 
than 30-mph first effectiveness values are adopted 
as proposed. 

The second effectiveness test (S5.1.1.2) is of 
the service brake system following burnish of 
the brakes and with the vehicles loaded to its 
GVWR. Comments were received from Wagner 
and International Harvester on the distance 
established for 30-mph stops, and from the 
VESC and ACTS on the full range of stopping 
distance requirements, for both light and heavy 
school buses. International made the same point 
that it made for other stopping distance tests: 
that the low-speed distances chosen as comparable 
to existing requirements are somewhat more dif- 
ficult due to Standard No. 105-75's specification 
of "no lockup" and pedal control force limits. 
In this case, however, the value chosen is far less 
demanding than that for the unbumished brakes, 
and the factors cited by International are not as 
crucial. 

Wagner assumed that the NHTSA, in adopt- 
ing existing school bus "equivalent distance" 
performance requirements for actual road tests, 
had not compensated for the fact that existing 
standards refer to deceleration rates measured 
by inertial decelerometers. Actually, the NHTSA 
did apply correction factors to compensate for 
this fact. Wagner's request for longer distances 
is denied for this reason. 

ACTS asked that the NHTSA set perform- 
ance requirements equal to those for other ve- 
hicles that share the highway with school buses. 
The VESC recommended decreased stopping 
distances roughly comparable to values for trucks 
and buses in Standard No. 105-75 before the 
standard was indefinitely delayed (40 FR 18411, 
April 28, 1975). For reasons established in the 
preamble to that decision, the NHTSA is con- 
sidering appropriate interim performance levels 



PART 571; S 105-75— PRE 38 



Effective: October 12, 1976 



for hydraulic-braked vehicles other than passen- 
ger cars, but is not prepared to specify perform- 
ance levels at this time. The ACTS and VESC 
requests will be considered as they apply to those 
interim requirements, but cannot be considered 
in this rulemaking because they would neces- 
sitate hardware changes that cannot be effec- 
tuated prior to the October 27, 1976, statutory 
deadline for effectiveness of this standard. 

The NHTSA proposed that second effective- 
ness performance requirements at speeds in excess 
of 60 mph not be specified for school buses. The 
VESC has argued that such requirements should 
apply to school buses if they have such high 
speed capability. WTiile the NHTSA cannot 
promulgate requirements in this area in the short 
period that remains prior to the standard's man- 
dated effectiveness, the VESC position will be 
considered in developing future standards for all 
vehicles other than passenger cars, including 
school buses. In view of the above, the second 
effectiveness distances are adopted as proposed. 

No comment was received on the requirements 
for lightly-loaded stopping distances (S5.1.1.3) 
other than those already discussed with regard 
to the second effectiveness test, and the proposed 
values are therefore also adopted. The second 
sentence of S5.1.1.3 (referring to vehicles to 
which the standard is no longer applicable) is 
also deleted as proposed. 

The fourth effectiveness test (S5.1.1.4) is of 
the abilities of the brake system after it has been 
subjected to fade and recovery testing under 
S5.1.4. Manufacturer comments indicated that, 
in the case of school buses with a GVWK greater 
than 10,000 pounds, use of a "hot" burnish pro- 
cedure (S7.4.2.1.2) in combination with the 
standard's fade and recovery testing makes the 
fourth effectiveness test redundant. NHTSA 
analysis agrees with these arguments, and in view 
of the fact that the hot burnish option will be- 
come the only permissible method of conditioning 
the brakes after September 1, 1976, the proposed 
fourth effectiveness test for heavier school buses 
is not adopted. 

Since use of the hot burnish procedure was 
an important factor in the decision to drop the 
fourth effectiveness requirement for vehicles over 
10,000 pounds GVWR, the NHTSA denies the 



Wagner petition to extend the alternative burnish 
procedures under S7.4.2.1 after the scheduled 
deletion of that option on September 1, 1976. 
Because this option ends before the standard's 
effectiveness for school buses, S7.4.2.1 has been 
simplified by eliminating the cold burnish pro- 
cedure, (S7.4.2.1.1) that will not be used. 

The NHTSA also notes General Motors' argu- 
ment that the fourth effectiveness test should be 
eliminated for vehicle classes offered with either 
hydraulic or air brakes simply because there is 
no comparable requirement in Standard No. 121, 
Air Brake Systems. Wliile the NHTSA agrees 
that vehicle classes ideally might be subjected 
to identical requirements whatever the method 
of brake actuation, formulation of any desired 
compatibility between hydraulic and air-braked 
vehicles of the same weight class must be accom- 
plished separately from this rulemaking on 
school buses, which is subject to a statutory dead- 
line. General Motors' view will be considered 
in future rulemaking. 

The April 28 notice proposed deletion, for 
school buses, of the option methods for testing 
the service brake system in the event the brake 
power assist or brake power unit failed (S5.1.3). 
The only comment received was from the VESC, 
which misunderstood the proposal as deleting all 
tests of a failed power assist or power unit. In 
fact, school buses will be required to meet 
S5.1.3.1 as hereby amended. The VESC mis- 
understanding may have arisen because of un- 
clear language used in proposing an amendment 
of the test procedure of S7.10 that underlies the 
requirement. Section S7.10 is appropriately re- 
vised in this amendment of the standard. 

The NHTSA proposed more stringent fade 
and recovery performance for school buses than 
the SAE's recommended levels for other truck- 
type vehicles, because of the distinctive school 
bus duty cycle. School buses make a high num- 
ber of stops compared to the truck-type vehicles 
which may share common components. These 
stops are usually made on secondary roads that 
often have steeper grades than the primary road 
system. The National School Transportation 
Association (NSTA) confirmed in statements 
before an NHTSA public meeting on hydraulic 
brakes that the association's experience indicated 



PART 571; S 105-75— PRE 39 



Effective: October 12, 1976 



inadequate fade resistance in some of today's 
school buses. While NHTSA testing indicates 
that some buses already conform to this require- 
ment, other buses will be required to upgrade 
their brake systems to conform to this minimum 
performance level. 

Three manufacturers objected to this perform- 
ance level and each suggested a different modifi- 
cation of the proposed requirement to reduce its 
stringency. Ford requested a 200-pound allow- 
able pedal force for the first five stops, stating 
that "The 60 mph fade sequence represents, in 
Ford's opinion, an extreme condition that would 
rarely, if ever, be duplicated in normal customer 
operation of school buses." Wagner stated "It 
is inconsistent to require one degree of vehicle 
braking for the Effectiveness Test and another 
(in this case, more powerful) for the Fade and 
Recovery. . . . We agree in the need for some 
measure of fade and recovery but the redundancy 
of two such requirements in a minimum standard 
has not been addressed. . . ." General Motors 
cited the good safety record of school buses, ques- 
tioned the adequacy of NHTSA testing, and 
stated, with regard to school buses with a GVWR 
of more than 10,000 pounds, ". . . . the NHTSA 
has proposed stringent fade and recovery require- 
ments which far exceed minimum performance 
requirements." 

"Minimum" performance standards do not 
equate with "minimal" perfonnance standards, 
as implied by General Motors and Wagner. The 
word "minimum" in the statutory definition of 
motor vehicle safety standards (15 U.S.C. § 1391- 
(2)), does not refer to the substantive content of 
the standards but rather to their legal status — 
that the products covered must not fall short of 
them. 

Wagner considered it inconsistent to specify a 
performance level for the fade characteristics of 
a braking system that would have the effect of 
improving another characteristic of the braking 
system (stopping distance performance) beyond 
the minimum level specified in the standard. The 
NHTSA disagrees, and considers it appropriate 
to specify the minimum fade performance neces- 
sary to assure adequate performance of brakes 
in stop-and-go operation, whether or not satis- 
faction of this minimtun level results in a brake 



system with better stopping distance performance 
than required by the standard. 

While Ford is correct that the test sequence 
typically will not be experienced in day-to-day 
operations, that does not rule out the need for 
the improved fade characteristics suggested by 
the NSTA. Each of the commenters claims that 
the fade and recovery characteristics do exceed 
the poorest performance of some existing vehicles, 
but none presented convincing justification for 
their positions that the proposed levels are in- 
appropriate for school bus braking systems. It 
is also noted that school buses with a GVWR 
of more than 10,000 pounds no longer have to 
meet the high-speed or fourth effectiveness re- 
quirements. With regard to Ford's suggestion 
of permitting a 200-pound pedal control force, 
the NHTSA continues to consider a 150-pound 
maximum necessary in view of the large per- 
centage of school bus operators that are women 
(see HSRI Report No. HuF-6, NBS Technical 
Note 557, October 1970, "The Brake Pedal Force 
Capability of Adult Females"). Accordingly, 
the fade and recovery performance values are 
pronmlgated as proposed. The proposed word- 
ing of S5.1.4.3(b) (2) is modified for clarity in 
response to Wagner's request. 

The proposal included a minimum performance 
level for the ability of school bus brakes to per- 
form after they are soaked with water. Three 
comments were received that objected to the pro- 
posed performance levels. Wagner also objected 
that the test conditions were stated with insuf- 
ficient specificity. The width of the water trough 
used to wet the brakes is not specified and the 
width may affect the degree of wetting acliieved 
in large truck tire sizes. The NHTSA intends 
to address this issue in its upcoming proposal on 
test intervals in the water recovery test. 

For the present NHTSA will resolve differ- 
ences in this test condition in the manufacturer's 
favor if they affect the outeome of testing. 

General Motors' only objection to inclusion of 
a water recovery test in this standard for school 
buses over 10,000 pounds GVWR was that a 
comparable test in Standard No. 121 has not been 
developed. The NHTSA is not, of course, limited 
in the breadth of one standard by the breadth 
of another, whether or not they measure the same 
aspect of performance of a vehicle. 



PART 571; S 105-75— PRE 40 



International was the only manufacturer to 
provide data indicating that its vehicles are not 
capable of meeting the water recovery test in all 
cases. The NHTSA concludes that other manu- 
facturers' products are capable of meeting the 
levels established in the standard. The NHTSA 
denies International's request to permit a 1.5- 
mile "drying-off" period between wet stops, be- 
cause it would negate for the most part the effect 
of soaking. 

Therefore, the only modification of water re- 
covery testing from that proposed is to clarify 
the wording of the minimum permissible control 
force (S5. 1.5.2(b) (2)) as requested by Wagner. 

The spike stop and parking brake requirements 
are amended as proposed. 

The test procedures contained in S6.1, S6.2, 
S7.5, S7.7.1, and S7.10 are revised as appropriate 
to reflect the amended requirements. 

Wagner, Ford, General Motors, and Inter- 
national requested that the brake fluid level indi- 
cator not be required for school buses. The 
NHTSA will make its decision in this area 
shortly and will publish its response to the issues 
raised in this rulemaking. 

Ford also asked that the parking brake warn- 
ing indicator be deleted from school bus require- 
ments as a luxury. The NHTSA has never 
considered this signal to be a luxury, and con- 
siders it important to prevent a partially-applied 
brake from overheating, reducing its efficiency. 
Ford's request is therefore denied. 

Wagner proposed that the present speed range 
for brake warming in S7.1 and S7.2 (40-to-lO- 
mph snubs) be increased to a range of 50-to-20- 
mph snubs. The agency has seen no evidence 
in its test program of the inadequacy of present 
values, and therefore denies the Wagner request, 
which was not supported by any data. 

The California Department of Highway Patrol 
(CHP) raised the issue of the adequacy of the 
standard from the enforcement perspective, 
particularly the complexity of the stopping dis- 
tance requirements for use in vehicle-in-use in- 
spection. As noted in a recent notice on air 
brakes (40 FK 56920, December 5, 1975), new 
vehicle braking standards may be inappropriate 
for a State inspection program, because they are 
not designed to measure degradation of equip- 
ment and performance over a period of time. 



Effective: October 12, 1976 

Since degradation of the brake system is not 
addressed by Standard No. 105-75, the CHP is 
not prevented by the National Traffic and Motor 
Vehicle Safety Act (15 U.S.C. 1392(d)) from 
enforcing requirements that measure the condi- 
tion of the vehicle, as long as they do not dictate 
the design or performance of new vehicles. 

The CHP recommendations for vacuum gauge 
and vacuum failure requirements on school buses 
equipped with vacuum-boosted brakes are being 
taken under consideration in regard to future 
rulemaking for truck, bus, and multi-purpose 
passenger vehicle hydraulic braking standards. 

SWS Silicon Corporation's comments on DOT 
5 brake fluid are noted, and comments of any 
interested person on the subject of appropriate 
brake fluids for school buses are solicited. 

In an area unrelated to the applicability of 
the standard to school buses, persons have re- 
quested clarification of an amendment of the 
standard published September 17, 1975 (40 FR 
42872). Section S5.1.5.2(a) consists of an open- 
ing paragraph, two numbered subparagraphs, 
and a concluding paragraph. Subparagraph 
"(2)" was set forth in its entirety in a revised 
form in that September action, and it was not 
clear whether the concluding paragraph that fol- 
lows it remained unchanged or was eliminated 
in the revision. For clarification, it is noted 
that only the subparagraph "(2)" was revised 
and that the concluding paragraph remains in 
the standard unchanged. 

In consideration of the foregoing. Standard 
No. 105-75 (49 CFE 571.105-75) is. . . . 

Effective date: Oct. 12, 1976. The effective 
date of this amendment is established as 9 months 
after the date of its issuance, as required by the 
Motor Vehicle and Schoolbus Safety Amend- 
ments of 1974, Pub. L. 93-^92, section 202 (15 
U.S.C. 1397(i)(l)(A)). 

(Sec. 103, 119, Pub. L. 89-563, 80 Stat. 718 
(15 U.S.C. 1392, 1407) ; § 202, Pub. L. 93-492, 
88 Stat. 1470 (15 U.S.C. 1392); delegation of 
authority at 49 CFR 1.50) 

Issued on January 12, 1976. 

James B. Gregory 
Administrator 
41 F.R. 2391 
January 16, 1976 



PART 571; S 105-75— PRE 41-42 



EffecHve: April 22, 1976 



PREAMBLE TO AMENDMENT TO MOTOR VEHICLE SAFETY STANDARD NO. 105-75 

Hydraulic Brake Systems 
(Docket No. 70-27; Notice 18) 



This notice amends Standard No. 105-75, 
Hydraulic Brake Systems, to permit a manufac- 
turer to provide either a gross loss of pressure 
indicator (GLPI) or a low brake fluid level indi- 
cator (BFLI) in satisfaction of the hydraulic 
failure indicator requirements of S5.3.1. 

This amendment of Standard No. 105-75 (49 
CFR 571.105-75) was proposed in response to 
petitions from Ford Motor Company, Wagner 
Electric Corporation, and Mercedes-Benz of 
North America, Inc., as well as the comments of 
other manufacturers of hydraulic-braked motor 
vehicles (41 FR 2828, January 20, 1976). 

Comments were received from General Motors 
Corporation, Bob Ingham, Jr., Chrysler Corpora- 
tion, Wagner Electric Corporation, the Cali- 
fornia Department of Highway Patrol (CHP), 
Professor P. N. Joubert, Bendix Corporation, 
British Leyland UK Limited, the Vehicle Equip- 
ment Safety Commission, Ford Motor Company, 
Bayerische Motoren Werke, and the Department 
of Transport of Australia. The National Motor 
Vehicle Safety Advisory Council made no com- 
ment on the proposal. 

All commenters except the CHP, VESC, De- 
partment of Transport of Australia, and Profes- 
sor Joubert endorsed the amendment as proposed 
and urged its swift implementation. 

The CHP recommended that the proposed op- 
tion be allowed only until the availability and 
reliability problems associated with the BFLI 
are resolved, at which time the BFLI would be 
required on all vehicles. The VESC also recom- 
mended a requirement for both of the devices or 
the BFLI alone. It is the opinion of the CHP 
that the apparent benefit of a GLPI is not real, 
because the GLPI warning activates only after 
failure has occurred, when increased pedal travel 
and decreased stopping performance have al- 



ready warned of the faulty condition. However, 
the failure of one subsystem in split system ve- 
hicles, particularly that to the rear wheels, easily 
may go unnoticed during the low rate-of- 
deceleration stops encountered in normal driving. 
In this vast majority of cases, the driver will be 
warned of the failure by the GLPI before the 
brake failure is apparent, a substantial benefit in 
averting accidents. 

Each of the four commenters who did not 
support the proposal found fault with the 
NHTSA's use of the extremely limited accident 
data from the Indiana University Institute for 
Research in Public Safety study {Tri-Level 
Study of the Causes of Traffic Accidents, DOT- 
HS-801-335, January, 1975). The four com- 
menters apparently interpreted Notice 17 to 
mean that the NHTSA had concluded, based on 
this small amount of data, that the BFLI was 
not cost-effective. Such is not the case. The 
NHTSA's evaluation of the Indiana study only 
concluded that its earlier judgement that both 
warnings were justified was cast in some doubt 
by the limited data generated since that initial 
decision was made. The NHTSA believes that 
the doubt is sufficient to justify dropping the 
simultaneous requirement for both devices. 

As noted by the CHP, the accident data are 
not yet available to quantitatively prove the com- 
parative benefits of one warning system over the 
other. Although the four dissenting comment- 
ers expressed a preference for the BFLI, the 
NHTSA feels that there is insufficient evidence 
of its superiority to mandate its use in place of 
the GLPI. The NHTSA believes that a con- 
tinuation of the option previously available 
under Standard No. 105 is in the public interest. 

Ford Motor Company pointed out that the 
proposed wording of S7.9.1, which refers to a 



PART 571; S 105-75— PRE 43 



Effective: April 22, 1976 

"brake system failure indicator," was inconsistent 
with other references in the standard, and sug- 
gested that the word "failure" be removed. The 
reference has been changed to read "brake system 
indicator lamp" to be consistent with S5.3. Sec- 
tion S7.9.4 also is reworded for the same reason. 

In a matter unrelated to the BFLI proposal, 
the agency hereby corrects an inadvertent omis- 
sion of a conforming amendment that should 
have accompanied the major amendment making 
the standard applicable to school buses (41 FR 
2391, January 16, 1976). The reference to 
"S7.4.2.1.2" in S6 is changed to "S7.4.2.1." 

In consideration of the foregoing. Standard 
No. 105-75 (49 CFR 571.105-75) is amended. . . . 



Effective date: April 22, 1976. Because this 
amendment creates no additional requirements 
for any person and because of the manufacturers' 
need to know as soon as jDossible the vehicle re- 
quirements for the upcoming model year for 
planning purposes, it is found that an immediate 
effective date is in the public interest. 

(Sec. 103, 119, Pub. L. 89-563, 80 Stat. 718 
(15 U.S.C. 1392, 1407) ; delegations of authority 
at 49 CFR 1.50 and 49 CFR 501.8.) 

Issued on April 14, 1976. 

James B. Gregory 
Administrator 

41 F.R. 16803 
April 22, 1976 



PART 571; S 105-75— PRE 44 



Effective: June 14, 1976 



PREAMBLE TO AMENDMENT TO MOTOR VEHICLE SAFETY STANDARD NO. 105-75 

Hydraulic Brake Systems 
(Docket No. 75-27; Notice 4) 



This notice amends Standard No. 105-75, 
Hydraulic Brake Systems, and Standard No. 122, 
Motorcycle Brake Systems, to modify the means 
for establishing the frictional resistance of the 
surface on which stopping distance tests are con- 
ducted. A similar amendment is made to Part 
575, Consumer Information, of Title 49 of the 
Code of Federal Regulations. 

The National Highway Traffic Safety Admin- 
istration (NHTSA) proposed the change in 
Standard No. 105-75 (49 CFR 571.105-75), 
Standard No. 121, Air Brake Systems (49 CFR 
571.121), Standard No. 122 (49 CFR 571.122), 
and the Consumer Information Regulations (49 
CFR 575.101) in response to a petition from 
British-Leyland Motors Limited (40 FR 45200, 
October 1, 1975). The existing test procedure in 
these regulations has specified use of the Ameri- 
can Society for Testing and Materials (ASTM) 
E-274-65T procedure, using an ASTM E249 tire 
that is no longer manufactured. 

Responses were received on the proposed 
ASTM change from White Motor Corporation 
(White), Mack Trucks, Inc. (Mack), Freight- 
liner Corporation (Freightliner), Ford Motor 
Company (Ford), General Motors Corporation 
(GM), Chrysler Corporation (Chrysler), Ameri- 
can Motors Corporation (AMC), and Interna- 
tional Harvester (IH). The National Motor 
Vehicle Safety Advisory Council made no com- 
ment on the proposal. 

Most commenters supported use of the new 
test procedure and tire, although they diflfered in 
recommendations for correlating the reading pro- 
duced under the new procedure with that pro- 
duced under the old procedure. Manufacturers 
are presently certifying compliance to brake 
standards on test surfaces with a satisfactory 
reading under the old procedure, and they should 



be able to continue testing and certifying com- 
pliance on the same surface without any increase 
in the severity of the tests. To accomplish this 
transition, the correlation in readings between 
the procedures has been determined, and the dif- 
ference is reflected in a change of the dry surface 
value from "skid number" 75 to "skid number" 
81. 

Freightliner urged postponement of any action 
until it could be supported by "adequate and 
statistically reliable test data." AMS also re- 
ommended that the NHTSA do nothing "until 
the industry has had sufficient time to evaluate 
and verify the performance of the ASTM E501 
test tire on all types of surfaces." 

The change in procedure is prompted by the 
ASTM decision to utilize a new tire in ascertain- 
ing the frictional coefficient of test surfaces. As 
a result the old tire is no longer manufactured 
and only the new tire is available for skid num- 
ber measurement. Manufacturers have conducted 
comparative tests with the new tire to determine 
the correlation between the readings given by the 
two tires. Neither Freightliner nor AMC sub- 
mitted data showing that the agency's proposal 
to adjust the dry surface skid number upwards 
is unjustified. Only Mack submitted data and it 
supported the NHTSA and Federal Highway 
Administration test data that have been placed 
in the docket. General Motors considered the 
agency's proposed upward adjustment to be the 
maximum desirable based on its data. Interna- 
tional Harvester, Chrysler, and Ford supported 
the change in dry surface skid number without 
qualification, and White suggested that a skid 
number of 85 be utilized. The agency finds that 
the AMC and Freightliner requests for further 
delay are unjustified. 



PART 571; S 105-75— PRE 45 



EffecHve: June 14, 1976 



Ford and Freightliner asked that the skid 
number for the lower coefficient (wet) surface 
also be adjusted. The agency's purpose in pro- 
posing the adjustment is limited to changes 
necessary to avoid a modification of the test sur- 
faces or an increase in the severity of perform- 
ance levels specified under the safety standards. 
The NHTSA earlier concluded that change of 
the wet surface specification was unnecessary, and 
no evidence has been supplied that would modify 
the earlier determination. 

General Motors noted that an editorial change 
to the newer ASTM procedure does not appear 
in early publications of that procedure. To put 
all interested persons on notice of the editorial 
change, the NHTSA has included the change in 
its references to the ASTM E274-70 procedure. 

Freightliner asserted that the newer procedure 
included modification of a formula that justified 
a larger upwards adjustment than that proposed 
by the agency. Actually, the modifications only 
corrected an error in the earlier formula which 
had no effect on the determination of frictional 
coefficient. Manufacturers either utilized a test 
trailer that obviated the need for calculations 
using the fonnula, or were aware of the error 
and corrected for it in their calculations. Thus 
the adjustment requested by Freightliner is not 
warranted. 

In accordance with recently-enunciated De- 
partment of Transportation policy encouraging 
adequate analysis of the consequences of regula- 
tory action (41 FR 16201, April 16, 1976), the 
agency herewith summarizes its evaluation of the 
economic and other consequences of this amend- 
ment on the public and private sectors, including 
possible loss of safety benefit. Because the new 
references to procedures and a test tire are ex- 
pected to accord with existing practices, the 
amendment is judged not to have any significant 



impact on costs or benefits of the standards and 
consumer information item that are modified by 
the change. 

Standard No. 121, Air Brake Systems, is pres- 
ently subject to judicial review under § 105(a) 
of the National Traffic and Motor Vehicle Safety 
Act (15 U.S.C. § 1394(a)). The U.S. Court of 
Appeals hearing the petition for review has in- 
dicated that it prefers to review the standard as 
it presently exists, without unnecessary amend- 
ment. To the degree possible, the agency is 
complying with that request and therefore, in the 
case of Standard No. 121, will delay the update 
of ASTM procedure until review is completed. 

It is noted that this change in procedure for 
ascertaining the frictional resistance of the test 
surface does not invalidate data collected using 
the older procedure, and manufacturers can pre- 
sumably certify on the basis of stopping distance 
tests conducted on sufaces measured by the old 
tire. 

In consideration of the foregoing, amendments 
are made in Chapter V of Title 49, Code of 
Federal Regulations. 

Elective date: June 14, 1976. Because the 
older test tire is no longer manufactured, and 
because the amendment of procedure and test tire 
is intended only to duplicate the existing proce- 
dure and tire, this amendment creates no addi- 
tional requirements for any person, and an 
immediate effective date is found to be in the 
public interest. 

(Sec. 103, 119, Pub. L. 89-563, 80 Stat. 718 
(15 U.S.C. 1392, 1407) ; delegation of authority 
at 49 CFR 1.50.) 

Issued on June 8, 1976. 

James B. Gregory 
Administrator 

41 F.R. 24592 
June 17, 1976 



PART 571; S 105-75— PRE 46 



Effectiv*: July 19, 1976 



PREAMBLE TO AMENDMENT TO MOTOR VEHICLE SAFETY STANDARD NO. 105-75 

Hydraulic Brake Systems 
(Docket Nos. 75-7; 75-16; Notices 3, 9) 



This notice republishes in their entirely Stand- 
ard No. 105-75, Hydraulic Brake Systems, and 
Standard No. 121, Air Brake Systems, because 
the number and complexity of recent amendments 
to these standards may have created confusion 
for some interested persons. 

Standard No. 105-75 (49 CFR 571.105-75) was 
issued September 1972 (37 FR 17970, September 
2, 1972) and has been amended numerous times 
since issuance. Although an up-to-date and com- 
plete text of the standard appears each year in 
the republished Code of Federal Regulations, 
several complex amendments have been made to 
the standard in the past year that are not re- 
flected in the most recent up-to-date text. To 
assist interested persons who must be certain of 
the text's provisions, the agency herewith pub- 
lishes the standard in its entirety. Interested 
persons are advised that amendments of Stand- 
ard No. 105-75 may occur in the future, although 
no proposals are outstanding at this time. 

In a related matter. General Motors Corpora- 
tion has brought to the agency's attention an 
inadvertent deletion of one sentence from one 
section of Standard No. 105-75. A statement 
was added to the text of S5.1.5.2(a) (2) to per- 
mit an interim increase in permissible control 
force for the fifth wet recovery stop (40 FR 
24525, June 9, 1975). Inadvertently, this sen- 
tence was deleted from So. 1.5.2(a) (2) in a sub- 
sequent rulemaking action (40 FR 42872, 
September 17, 1975), although the preamble to 
the notice made clear that "The new wording in 
no way modifies the meaning of S5.1.4(a)(2) 
and S5.1.5.2(a) (2)." To correct this omission, 
the sentence appears in this publication. It has 



been moved to S5.1.5.2(a) (1) because it concerns 
the maximum pedal force limit in that section, 
rather than the minimum pedal force limit in 
S5.1.5.2(a) (2) where it appeared in the past. 

Standard No. 121 (49 CFR 571.121) was issued 
in February 1971 (36 FR 3817, February 27, 
1971) and has also been amended numerous times 
since issuance. Several amendments have oc- 
curred since the most recent publication of the 
standard in its entirety. For the reasons cited 
with regard to Standard No. 105-75, the agency 
herewith publishes the standard in its entirety. 
Interested persons are advised that three pro- 
posals to amend the standard are outstanding 
(40 FR 45200, October 1, 1975) (40 FR 56920, 
December 5, 1975) (41 FR 20706, May 20, 1976) 
and that amendments to the text of the standard 
may be made in the future. 

It has also been noted that a clarification could 
be made to the language of S3 of the standard 
that excludes until September 1, 1977, vehicles 
that combine with other vehicles to foma auto 
transporters. The temporary exclusion was 
added to the standard in January 1975 (40 FR 
1246, January 7, 1975). To make the effect of 
that action more clear, the language in the second 
sentence of the text "or to any vehicle which" is 
changed in this republication to read "or that." 
This modification of the language has no effect 
on the requirements of this standard and notice 
and opportunity to comment are therefore found 
to be unnecessary. 

In consideration of the foregoing. Standard 
No. 105-75 (49 CFR 571.105-75) and Standard 
No. 121 (49 CFR 571.121) are republished to 
read as set forth below. 



PART 571; S 105-75— PRE 47 



Effective: July 19, 1976 

(Sec. 103, 119, Pub. L. 89-563, 80 Stat. 718 Robert L. Carter 

(15 U.S.C. 1392, 1407) ; delegations of authority Associate Administrator 

at 49 CFR 1.50 and 49 CFR 501.8.) Motor Vehicle Programs 

Issued on June 30, 1976. 41 f.r. 29696 

July 19, 1976 



PART 571; S 105-75— PRE 48 



Effective: August 26, 1976 



PREAMBLE TO AMENDMENT TO MOTOR VEHICLE SAFETY STANDARD NO. 105-75 

Hydraulic Brake Systems 

(Docket No. 73-03; Notice 7); (Docket No. 73-20; Notice 10); 

(Docket No. 73-34; Notice 4); (Docket No. 75-02; Notice 3); 

(Docket No. 75-03; Notice 5); (Docket No. 75-07; Notice 3); 

(Docket No. 75-24; Notice 3) 



This notice announces that the effective dates 
of the redefinition of "school bus" and of six 
Federal motor vehicle safety standards as they 
apply to school buses are changed to April 1, 
1977, from the previously established effective 
dates. This notice also makes a minor amend- 
ment to Standard No. 220, School Bus Rollover 
Protection, and adds a figure to Standard No. 
221, School Bus Body Joint Strength. 

The Motor Vehicle and Schoolbus Safety 
Amendments of 1974 (the Act) mandated the 
issuance of Federal motor vehicle safety stand- 
ards for several aspects of school bus perform- 
ance, Pub. L. 93-492, §202 (15 U.S.C. §1392 
(i) (1) (A) ). These amendments included a defi- 
nition of school bus that necessitated a revision 
of the existing definition used by the NHTSA 
in establishing safety requirements. The Act 
also specified that the new requirements "apply 
to each schoolbus and item of schoolbus equip- 
ment which is manufactured ... on or after the 
expiration of the 9-month period which begins 
on the date of promulgation of such safety 
standards." (15 U.S.C. § 1392(i) (1) (B) ). 

Pursuant to the Act, amendments were made 
to the following standards : Standard No. 301-75, 
Fuel System Integrity (49 CFR 571.301-75), 
effective July 15, 1976, for school buses not al- 
ready covered by the standard (40 FR 483521, 
October 15, 1975); Standard No. 105-75, Hy- 
draulic Brake Systems (49 CFR 571.105-75), ef- 
fective October 12, 1976 (41 FR 2391, January 
16, 1976) ; and Standard No. 217, Bus Window 
Retention and Release (49 CFR 571.217), effec- 



tive for school buses on October 26, 1976 (41 FR 
3871, January 27, 1976). 

In addition, the following new standards were 
added to Part 571 of Title 49 of the Code of 
Federal Regulations, effective October 26, 1976: 
Standard No. 220, School Bus Rollover Protec- 
tion (41 FR 3874, January 27, 1976) ; Standard 
No. 221, School Bus Body Joint Strength (41 
FR 3872, January 26, 1976) ; and Standard No. 
222, School Bus Passenger Seating and Crash 
Protection (41 FR 4016, January 28, 1976). Also, 
the existing definition of "school bus" was 
amended, effective October 27, 1976, in line with 
the date set by the Act for issuance of the stand- 
ards. 

The Act was recently amended by Public Law 
94^346 (July 8, 1976) to change the effective 
dates of the school bus standards to April 1, 
1977 (15 U.S.C. §1392(i)(l)(B)). This notice 
is intended to advise interested persons of these 
changes of effective dates. In the case of Stand- 
ard No. 301-75, the change of effective date is 
reflected in a conforming amendment to S5.4 of 
that standard. A similar amendment is made in 
S3 of Standard No. 105-75. 

The agency concludes that the October 27, 
1976, effective date for the redefinition of "school 
bus" should be postponed to April 1, 1977, to 
conform to the new effective dates for the up- 
coming requirements. If this were not done, the 
new classes of school buses would be required to 
meet existing standards that apply to school 
buses (e.g.. Standard No. 108 (49 CFR 571.108)) 
before being required to meet the new standards. 
This would result in two stages of compliance, 



PART 571; S 105-75— PRE 49 



EffecHve: August 26, 1976 



and would complicate the redesign efforts that 
Congress sought to relieve. 

This notice also amends Standard No. 220 in 
response to an interpretation request by Blue 
Bird Body Company, and Sheller-Globe Cor- 
poration's petition for reconsideration of the 
standard. Both companies request confirmation 
that the standard's requirement to operate emer- 
gency exits during the application of force to the 
vehicle roof (S4(b)) does not apply to roof 
exits which are covered by the force application 
plate. The agency did not intend to require the 
operation of roof exits while the force applica- 
tion plate is in place on the vehicle. Accordingly, 
an appropriate amendment has been made to 
S4(b) of the standard. 

With regard to Standard No. 220, Sheller- 
Globe also requested confirmation that, in testing 
its school buses that have a gross vehicle weight 
rating (GVIVR) of 10,000 pounds or less, it may 
test with a force application plate witli dimen- 
sions other than those specified in the standard. 
The standard does not prohibit a manufacturer 
from using a different dimension from that speci- 
fied, in view of the NHTSA's expressed position 
on the legal effect of its regulations. To certify 
compliance, a manufacturer is free to choose any 
means, in the exercise of due care, to show that 
a vehicle (or item of motor vehicle equipment) 
would comply if tested by the NHTSA as speci- 
fied in the standard. Thus the force application 
plate used by the NHTSA need not be dupli- 
cated by each manufacturer or compliance test 
facility. Sheller-Globe, for example, is free to 
use a force application plate of any width as 
long as it can certify its vehicle would comply 
if tested by the NHTSA according to the stand- 
ard. 

In a separate area, the agency corrects the in- 
advertent omission of an illustration from 
Standard No. 221 as it was issued January 26, 
1976 (41 FR 3872). The figure does not differ 
from that proposed and, in that form, it received 
no adverse comment. 

In accordance with recently-enunciated De- 
partment of Transportation policy encouraging 



adequate analysis of the consequences of regula- 
tory action (41 FR 16200, April 16, 1976), the 
agency herewith summarizes its evaluation of the 
economic and other consequences of this action 
on the public and private sectors, including pos- 
sible loss of safety benefits. The changes in 
effective dates for the school bus standards are 
not evaluated because they were accomplished by 
law and not by regulatory action. 

The change of effective date for the redefini- 
tion of "school bus" will result in savings to 
manufacturers who will not be required to meet 
existing school bus standards between October 
27, 1976, and April 1, 1977. The agency calcu- 
lates that the only standard that would not be 
met would be the requirement in Standard No. 
108 for school bus marker lamps. In view of the 
agency's existing provision for the markings of 
eight school buses in Pupil Transportation 
Standard No. 17 (23 CFR 1204), it is concluded 
that the absence of this equipment until April 1, 
1977, will not have a significant adverse impact 
on safety. 

The interpretative amendment of Standard No. 

220 and the addition of a figure to Standard No. 

221 are not expected to affect the manufacture or 
operation of school buses. 

In consideration of the foregoing, Part 571 of 
Title 49 of the Code of Federal Regulations is 
amended. . . . 

Effective dates: 

1. Because the listed amendments do not im- 
pose additional requirements of any person, the 
National Highway Traffic Safety Administration 
finds that an immediate effective date of August 
20, 1976 is in the public interest. 

2. The effective date of the redefinition of 
"school bus" in 49 CFR Part 571.3 that was 
published in the issue of December 31, 1976 (40 
FR 60033) is changed to April 1, 1977. 

3. The effective dates of Standard Nos. 105-75, 
217, 301-75, 220, 221, and 222 (as they apply to 
school buses) are April 1, 1977, in accordance 
with Public Law 94-346. 

(Sec. 103, 119, Pub. L. 89-563, 80 Stat. 718 
(15 U.S.C. 1392, 1407); Pub. L. 94-346, Stat. 



PART 571; S 105-75— PRE 50 



Effective; August 26, 1976 

(15 U.S.C. §1392(i)(l)(B)); delegation of John W. Snow 

authority at 49 CFR 1.50.) Administrator 

Issued on August 17, 1976. 41 F R 36026 

August 26, 1976 



PART 571; S 105-75— PRE 51-52 



PREAMBLE TO FEDERAL MOTOR VEHICLE SAFETY STANDARD NO. 105-83 



Hydraulic Brake Systems 
(Docket No. 70-27; Notice 20) 



ACTION: Final rule. 



SUMMARY: This notice amends Standard 105, 
Hydraulic Brake Systems. The standard current- 
ly applies to passenger cars and school buses. Its 
applicability is extended on a general basis (with 
some modifications) to trucks, all types of buses, 
and multipurpose passenger vehicles (MPV's) 
with a gross vehicle weight rating (GVWR) of 
10,000 lbs. or less. Several requirements are also 
extended to trucks, buses and MPV's with a 
GVWR greater than 10,000 lbs. In addition, the 
standard's requirements for school buses are 
upgraded. 

DATES: The effective date of this amendment is 
September 1, 1983. 

ADDRESSES: Petitions for reconsideration should 
refer to the docket number and be submitted to: 
Docket Section, Room 5108, 400 Seventh Street, 
S.W., Washington, D.C. 20590. 

FOR FURTHER INFORMATION CONTACT: 
Mr. George L. Parker, Office of Vehicle 
Safety Standards, National Highway Traffic 
Safety Administration, 400 Seventh Street 
S.W., Washington D.C. 20590 
(202-426-2720) 

SUPPLEMENTARY INFORMATION: Standard 105, 
Hydraulic Brake Systems, currently applies to 
passenger cars and school buses. This notice ex- 
tends its applicability on a general basis (with 
some modifications) to trucks, all types of buses, 
and multipurpose passenger vehicles (MPV's) 
with a gross vehicle weight rating (GVWR) of 
10,000 lbs. or less. Several requirements are also 
extended to trucks, buses and MPV's with a 
GVWR greater than 10,000 lbs. In addition, the 



standard's requirements for school buses are 
upgraded. 

This final rule was preceded by a notice propos- 
ing the extension of Standard 105 in October 1979 
(44 FR 60113). Private citizens, safety organiza- 
tions, manufacturers, and manufacturer trade 
associations have submitted comments on the 
proposal. The NHTSA has considered all of those 
comments and the most significant ones are dis- 
cussed below. 

The agency made two significant modifications 
in the proposed standard's requirements as a 
result of the comments. As will be explained 
below, the agency determined that third effec- 
tiveness requirements should not be applicable to 
vehicles, other than school buses, with a GVWR 
of 8,000 to 10,000 lbs. Also, the agency deter- 
mined that fourth effectiveness stopping distance 
requirements for vehicles with a GVWR of 8,000 
to 10,000 lbs., as well as spike stop check stopping 
distance requirements for those vehicles, should 
be slightly relaxed. 

The changes in the standard's requirements 
were made to give manufacturers additional 
leeway in balancing the performance of their 
vehicles' braking systems for both fully loaded 
and lightly loaded conditions and to ensure that 
the requirements would not result in unduly 
burdensome certification responsibilities being 
imposed on final stage manufacturers. 

A slight change was also made in the 
standard's definition of "lightly loaded vehicle 
weight" to permit the use of additional in- 
strumentation. 

Also in response to the comments, the agency 
determined that a longer period of leadtime 
should be provided. The effective date of the re- 
quirements is September 1, 1983, which gives a 
leadtime of more than two years. 

Many comments were received in support of 



PART 571; S 105-83-PRE 53 



extending Standard 105 to to apply to trucks, all 
types of buses, and MPV's. General Motors, 
Chrysler and American Motors/Jeep all stated 
that they support the adoption of requirements 
for hydraulic braked trucks, buses and MPV's, 
though all three companies requested some 
modifications in the standard as proposed. 
Wagner Electric stated that it is commendable 
that efforts are being made to improve the safety 
of the highways and that it can see the benefits 
that may accrue when more varieties of highway 
vehicles have been brought under the control of 
the appropriate minimum braking standard. 

Both Ford and the Japan Automobile Manufac- 
turers Association stated that they are not op- 
posed to the application of braking performance 
requirements to vehicles in addition to passenger 
cars and school buses. The Japan Automobile 
Manufacturers Association added that, from the 
viewpoint of safety, it thought this application 
should be promoted. 

The National Transportation Safety Board 
stated that it supported the action, noting that by 
reducing the current disparity between the brak- 
ing capability of passenger cars and many trucks 
and vans, motor vehicle accidents should be 
reduced. The Board also stated its support for the 
requirements upgrading the performance re- 
quirements for school buses. 

While the General Accounting Office of the 
United States did not specifically comment on 
this rulemaking, a report to the United States 
Congress by the Comptroller General issued in 
1978 called for, among other things, expeditious 
rulemaking on light truck braking performance. 
See Report to Congress by the Comptroller 
General of the United States, Unwarranted 
Delays by the Department of Transportation to 
Improve Light Truck Safety, July 6, 1978. 

The Center for Auto Safety stated that exten- 
sion of the standard is long overdue and is fully 
supported by the large number of consumer com- 
plaints that the Center received each year on in- 
adequate brakes on light trucks, vans and MPV's. 

Effectiveness Requirements 

Comments received on the proposal's effec- 
tiveness requirements for service brake systems 
primarily dealt with the third and fourth effec- 
tiveness test stopping distances for vehicles with 
a GVWR of 8,000 to 10,000 lbs. Several comments 



stated that the stopping distance requirements 
that were proposed were too stringent. 

The fourth effectiveness test is an effec- 
tiveness test of the braking system which is con- 
ducted after the fade tests and while the vehicle 
is fully loaded. Because it comes after the fade 
tests, during which some deterioration of the 
brakes may occur, the fourth effectiveness test 
was considered by several commenters to be the 
most stringent of the fully loaded effectiveness 
tests. Generally discussed along with the fourth 
effectiveness test were the spike stop check stop- 
ping distance requirements. These requirements 
represent an abbreviated effectiveness test with 
the same stopping distance requirements as the 
fourth effectiveness test, which is conducted 
after the spike stops (which follow the fourth ef- 
fectiveness test). Because the commenters ad- 
dressed these tests together and because the 
stopping distance requirements are the same for 
the two tests, the discussion of these re- 
quirements will subsume the spike stop check 
stopping distance requirements into considera- 
tion of the fourth effectiveness stopping distance 
requirements. 

According to the commenters, brakes which 
are powerful enough to meet the fourth effec- 
tiveness (fully loaded) stopping distance re- 
quirements for vehicles in that weight class 
would be prone to lockup in the lightly loaded con- 
dition. If lockup occurred in the lightly loaded 
condition, the vehicles would be unable to meet 
the third effectiveness (lightly loaded) stopping 
distance requirements. Several comments stated 
that manufacturers would find it necessary to 
develop anti-lock or similar devices in order to 
meet the requirements as proposed. 

Other comments on the third and fourth effec- 
tiveness requirements for this class of vehicles 
focused on possible deleterious effects that the 
requirements might have on final stage manufac- 
turers and the market which they serve. (A "final 
stage manufacturer" is a manufacturer which 
typically purchases an incomplete vehicle which 
usually consists only of a chassis, suspension, 
power train, brakes and perhaps an occupant 
compartment from an incomplete vehicle manu- 
facturer such as Ford, General Motors or 
Chrysler and completes the vehicle by adding a 
body or work-performing equipment). 

Any final stage manufacturer that does not 



PART 571; S 105-83-PRE 54 



complete a vehicle in accordance with conditions 
established by the incomplete vehicle manufac- 
turer must recertify that the completed vehicle 
complies with applicable safety standards based 
upon its own information, analysis, or tests. 
Several commenters were concerned that final 
stage manufacturers would not be able to meet 
those conditions and thus would be required to 
engage in extensive testing of their vehicles. Ac- 
cording to those commenters, extensive testing is 
not feasible for final stage manufacturers as they 
are often small manufacturers that produce only 
limited numbers of a variety of specialty vehicles. 

Changes suggested by the commenters varied, 
depending upon whether they were addressing 
the requirements from the point of view of the 
large manufacturers (i.e., the incomplete vehicle 
manufacturers) or the final stage manufacturers. 
General Motors, for example, stated that it could 
meet the longest of a range of stopping distances 
proposed for the third effectiveness test if fourth 
effectiveness test stopping distances were ex- 
tended by 10 percent. Comments received from 
Ford and Chrysler were similar, with Ford asking 
for a relatively minor increase in third effec- 
tiveness stopping distances and a 10 percent in- 
crease in fourth effectiveness stopping distances, 
while Chrysler requested a 16 percent increase in 
stopping distances for fourth effectiveness tests. 

Those commenters primarily concerned with 
final stage manufacturer certification difficulties 
suggested various approaches, including not 
extending Standard 105 at this time or only ex- 
tending it to vehicles with a GVWR under 8,000 
lbs. Other approaches suggested by those com- 
menters include applying different test re- 
quirements to final stage manufacturers, so long 
as the braking systems on their vehicles are used 
on similar vehicles, requiring incomplete vehicle 
manufacturers to give additional information to 
final stage manufacturers to help them make 
engineering judgments about the effect changes 
in the center of gravity will have on a vehicle's 
braking ability, and providing a longer period of 
leadtime to final stage manufacturers than other 
manufacturers. 

The latter approach was suggested because 
some final stage manufacturers were concerned 
that incomplete vehicle manufacturers would not 
provide information about new conditions estab- 
lished as a result of the proposed requirements 



until just before the time of model introduc- 
tion. According to those comments, final stage 
manufacturers need to receive such information 
well in advance of the time of model introduction 
in order that they can design their vehicles in 
accordance with the conditions. 

The agency was aware of the braking design 
problems associated with trucks, buses and 
MPV's, including those particularly affecting 
vehicles over 8,000 lbs. GVWR, when it issued the 
proposal. The proposal explained that while 
trucks, buses and MPV's should ideally stop in as 
short a distance as passenger cars, since they 
share the same roads and traffic flow, there are 
certain differences between those vehicles which 
make accomplishing that goal more difficult for 
trucks, buses and MPV's. The primary dif- 
ferences are the greater loaded to empty-weight 
ratio of trucks, MPV's and buses, the higher 
center of gravity found in those vehicles (which 
results in greater dynamic weight transfer dur- 
ing braking), the greater variations in loaded and 
unloaded weight distribution that occur in those 
vehicles and the lower traction capabilities of 
truck tires. Because these factors make it difficult 
to design braking systems which provide the ap- 
propriate brake torque for each axle under all 
braking and load conditions, the agency proposed 
stopping distances that were slightly longer than 
those in effect for passenger cars. 

The notice also discussed the design problems 
particularly affecting trucks, buses and MPV's 
with a GVWR over 8,000 lbs. In order to stop in as 
short a distance as lighter vehicles, vehicles with 
GVWR of 8,000 lbs. or more require powerful rear 
brakes to meet fully loaded stopping distance re- 
quirements. When the vehicles are stopped in a 
lightly loaded condition, however, the powerful 
rear brakes can cause wheel-lockup and resulting 
vehicle instability. Because of these design prob- 
lems, the agency proposed ranges of slightly 
longer third effectiveness test stopping distances 
for vehicles with a GVWR of 8,000 to 10,000 lbs 
than for vehicles with lower GVWR. In proposing 
the requirements, the agency stated that it was 
its intention to avoid requiring manufacturers to 
develop anti-lock or similar devices for their 
vehicles. While such systems may be able to over- 
come these problems, there is no field-tested anti- 
lock system for hydraulic-braked vehicles that is 
commercially available at this time. 



PART 571; S 105-83-PRE 55 



The stopping distances proposed for the third 
and fourth effectiveness tests were based upon 
tests conducted by the agency on existing produc- 
tion vehicles and upon confidential brake develop- 
ment test data submitted by General Motors, Ford 
and Chrysler. Based upon its analysis of these data, 
the agency concluded that the proposed stopping 
distances for both the third and fourth effec- 
tiveness tests for vehicles with a GVWR of 8,000 to 
10,000 lbs., including vehicles with unusually high 
centers of gravity and with both short and long 
wheelbases (which typically are more difficult to 
design brakes for than other vehicles), could be 
met without anti-lock or similar devices. Instead, 
the requirements could be met by modifications to 
such vehicle components as brake linings, wheel 
cylinders, master cylinders, and combination 
valves. 

This conclusion does not, however, fully resolve 
the concerns raised about the requirements as 
they relate to final stage manufacturers. As noted 
above, final stage manufacturers, typically pur- 
chase incomplete vehicles from large manufac- 
turers and complete the vehicles, often for 
specialized needs. Since only a limited number of 
incomplete vehicle designs are available for pur- 
chase, a final stage manufacturer must use the 
same incomplete vehicle design for widely varying 
applications. A given incomplete vehicle design 
may be completed as a pickup, a recreational vehi- 
cle, or a high cube van. Diverse equipment may be 
added such as service cranes, lift gates, ladders, 
aerial devices, and snow plows. Assuming that a 
final stage manufacturer does not redesign the 
braking system for each different use, the braking 
system sold with the incomplete vehicle by its 
manufacturer must serve applications with widely 
varying centers of gravity (i.e., varying both ver- 
tically and horizontally). 

The agency estimates that a 10 percent rise in 
center of gravity location will lengthen the stop- 
ping distance of a typical vehicle by three percent 
if it is operating at the limit of tire traction for its 
rear wheels. Changes in horizontal center of grav- 
ity will also lengthen stopping distances in some in- 
stances. It follows that a vehicle which would 
barely meet the requirements of the proposed 
standard at the specific center of gravity for which 
it is designed, which would be the case for some 
vehicles with a GVWR of 8,000 to 10,000 lbs., would 
not be able to meet the requirements at centers 



of gravity widely varying from the design one. 

The agency agrees, after analysis of the com- 
ments received from final stage manufacturers, 
their trade associations, and incomplete vehicle 
manufacturers, that the increased center of gravi- 
ty limitations which might be established for some 
vehicles of 8,000 to 10,000 lbs. GVWR if the pro- 
posal were adopted would pose significant dif- 
ficulties for final stage manufacturers. (Some 
limitations are currently established by in- 
complete vehicle manufacturers in connection with 
their certification of Standards 212, 219, and 301.) 
In some instances, a final stage manufacturer 
would be unable to simply complete vehicles on the 
same incomplete vehicle that it is accustomed to 
using, as the center of gravity of the completed 
vehicles would not be within the center of gravity 
envelope specified by the incomplete vehicle 
manufacturer. 

The final stage manufacturer would be faced 
with buying the same incomplete vehicles as 
before and recertifying them and possibly rede- 
signing their braking systems. Since the sales of in- 
complete vehicles to final stage manufacturers are 
a very small percentage of the light truck sales of 
the incomplete vehicle manufacturers, the in- 
complete vehicle manufacturers are not likely to 
be willing to accommodate the final stage manufac- 
turers by making major modifications to the line of 
incomplete vehicles they offer for sale, such as pro- 
viding incomplete vehicles which are designed for 
a broader range of centers of gravity. The in- 
complete vehicle manufacturers have themselves 
indicated this reluctance in a number of rulemak- 
ings. 

The agency has dealt with the certification prob- 
lems of final stage manufacturers during other 
rulemaking proceedings. Since final stage manu- 
facturers are often very small companies, which 
produce limited numbers of speciality vehicles, 
they often have limited resources for redesign- 
ing their vehicles, testing their vehicles for compli- 
ance with applicable safety standards, or making 
engineering judgments about the effect changes in 
a vehicle's center of gravity will have on the vehi- 
cle's performance. Therefore, the agency has 
sought to limit, consistent with the needs of safety, 
the compliance burdens on final stage manufac- 
turers. 

For example, the agency established special pro- 
visions affording relief to final stage manufac- 



PART 571; S 105-83-PRE 56 



turers in Standards 212, Windshield Mounting, 
and 219, Windshield Zone Intrusion. See notice of 
Final Rule, published in the Federal Register (45 
FR 22044) on April 3, 1980. One of the final stage 
manufacturer problems that was addressed in 
that rulemaking proceeding was center of gravity 
limitations established by incomplete vehicle 
manufacturers. The agency added the special pro- 
visions to Standards 212 and 219 for the purpose 
of inducing the reduction of center of gravity 
restrictions placed on final stage manufacturers 
by incomplete vehicle manufacturers. 

In order to ease the certification problems of 
final stage manufacturers that are related to 
Standard 105, while providing the maximum 
safety benefits that are consistent with that ob- 
jective, the agency determined that third effec- 
tiveness requirements should not apply to 
vehicles, other than school buses, with a GVWR 
of 8,000 to 10,000 lbs. The problem of center of 
gravity limitations as it relates to the proposed 
test requirements is primarily limited to the third 
effectiveness (lightly loaded) test. Since the test 
is conducted while the vehicle is in an unloaded 
condition, the manufacturer is constrained to test 
at the vehicle's center of gravity of the vehicle as 
configured. Center of gravity is not a serious 
problem for the other effectiveness tests, which 
are conducted at GVWR. For those tests, the 
manufacturer may load the vehicle in a way so as 
to lower the center of gravity and make com- 
pliance easier. 

In order to provide manufacturers with some 
additional leeway in balancing the performance of 
their braking systems for both fully loaded and 
lightly loaded conditions, the agency also decided 
that the fourth effectiveness (fully loaded) stop- 
ping distances should be extended by approx- 
imately 10 percent for the 8,000 to 10,000 lb. 
GVWR vehicles. As noted above, if fourth effec- 
tiveness requirements are too stringent, vehicles 
would need overly powerful rear brakes that are 
prone to lock-up in the lightly loaded condition. 
The agency recognizes that it is more difficult to 
meet the proposed fourth effectiveness require- 
ments for this class of vehicles without producing 
vehicles that are prone to lock-up, though, as 
indicated above, test data indicate that it can 
be accomplished. The relaxation of the fourth 
effectiveness requirements will assure that the 
manufacturers can use braking systems that 



perform well in the lightly loaded condition. 

In making these modifications to the proposed 
requirements for vehicles with a GVWR of 8,000 
to 10,000 lbs., the agency decided that school 
buses within that weight class should be treated 
separately. School buses are already required to 
meet Standard 105's requirements, though the 
October 1979 notice proposed making the re- 
quirements more stringent. As will be explained 
below, the agency decided that the proposal's 
fourth effectiveness requirements for school 
buses with a GVWR of 8,000 to 10,000 lbs. should 
be extended by 10 percent (the same as other 
vehicles within that weight class), with the excep- 
tion of the 30 mph test. The agency also decided 
that third effectiveness stopping distance re- 
quirements, at the longest distances proposed, 
should be applicable to school buses. 

Since school buses are already covered by 
Standard 105, the agency has a great deal of test 
data indicating their braking capability. Because 
school buses with a GVWR of 8,000 to 10,000 lbs. 
share most of the same characteristics as other 
vehicles with the same weight, the agency de- 
cided that fully loaded effectiveness require- 
ments should be the same for school buses as for 
other vehicles, with the one exception referred to 
above. School buses are already required to meet 
slightly more stringent requirements for fully 
loaded tests at 30 mph. Therefore, the agency will 
not relax those requirements. For fully loaded 
tests at other speeds, the requirements are more 
stringent than those currently in effect. 

As noted above, both agency test data and 
several comments indicate that the proposed 
third effectiveness test requirements (at the 
longest stopping distances proposed) can be met 
by vehicles with a GVWR of 8,000 to 10,000 lbs., 
particularly when the proposed fourth effec- 
tiveness stopping distances are slightly relaxed. 
The agency's decision that third effectiveness 
test requirements should not be applicable to 
vehicles with a GVWR of 8,000 to 10,000 lbs. 
resulted from possible center of gravity condi- 
tions that incomplete vehicle manufacturers 
might establish for the use of their vehicles. Since 
school buses do not have high centers of gravity 
or widely varying horizontal centers of gravity, 
they do not pose the same problems for final 
stage manufacturers as other vehicles. Moreover, 
since completing a vehicle as a school bus adds 



PART 571; S 105-83-PRE 57 



weight to the rear axle, the lightly loaded effec- 
tiveness test is more easily met by school buses 
than many other vehicles. The comments re- 
ceived that related to third effectiveness tests 
and final stage manufacturer difficulties did not 
identify the requirements for school buses as 
creating difficulties. Therefore, based upon a 
detailed analysis of test data, manufacturer- 
supplied information, and the comments, as well 
as on the safety need associated with school 
buses, the agency decided that third effec- 
tiveness test requirements should apply to school 
buses with a GVWR of 8,000 to 10,000 lbs. 

The agency believes that the modifications in 
the standard that were discussed above will 
eliminate any possibility that incomplete vehicle 
manufacturers will find it necessary either to 
establish more stringent center of gravity limita- 
tions on the use of their incomplete vehicles or to 
develop anti-lock or similar devices in order to be 
able to continue to produce incomplete vehicles 
that comply with the standard for the range of ap- 
plications needed by final stage manufacturers. 
Final stage manufacturers, therefore, will or- 
dinarily be able to rely on the incomplete vehicle 
manufacturer's certification of the braking 
system. 

In some rare cases, such as when a final stage 
manufacturer adds an axle or redesigns the brak- 
ing system of an incomplete vehicle, the final 
stage manufacturer will be required to recertify 
that the completed vehicle complies with the 
brake requirements. Depending upon the changes 
made, the final stage manufacturer may be able 
to certify based upon engineering judgments. If 
testing is required, the agency estimates that the 
costs of a full test sequence would be approx- 
imately $2,500, assuming that the manufacturer 
has no facilities, instrumentation or test person- 
nel of its own. Testing would not have to be con- 
ducted for each vehicle, but only for each vehicle 
type or, in some cases, the most problem prone 
configuration of several vehicle types. There are 
several test facilities and testing organizations 
distributed throughout the United States. 

Such major changes are rarely made by final 
stage manufacturers, and, if they are, they tend 
to be made by the larger of these manufacturers. 
When such changes are made, the agency 
believes it appropriate to require that the 
manufacturer making those changes ensure that 



the vehicle still complies with applicable Federal 
motor vehicle safety standards. 

In adopting these changes, the agency fol- 
lowed, in part, the suggestions of several of the 
commenters. The National Truck Equipment 
Association (NTEA), for example, suggested that 
if the agency extends the standard at this time, it 
should select 8,000 lbs. GVWR as the cutoff 
weight for Standard 105. That cutoff was said to 
address the brake proportioning difficulties in- 
herent in vehicles with a wide weight differential 
in their laden and unladen conditions. The agency 
declined to completely exempt vehicles of 8,000 
lbs. or greater GVWR from Standard 105's cover- 
age, since the standard offers many benefits in 
addition to those resulting from the requirements 
that would cause difficulties for final stage 
manufacturers. However, the agency did use 
8,000 lbs. GVWR as the cutoff weight for the 
standard's third effectiveness requirements, the 
requirements which most directly relate to the 
brake proportioning difficulties referred to by 
NTEA. 

The agency followed the suggestions of several 
incomplete vehicle manufacturers and other com- 
menters also in deciding to relax fourth effec- 
tiveness stopping distance requirements for 8,000 
to 10,000 lb. GVWR vehicles. Since the agency 
concluded that the requirements could be met as 
proposed without anti-lock or similar devices, 
albeit with some difficulty, the agency declined to 
adopt Chrysler's suggestion of a 16 percent ex- 
tension and instead chose the 10 percent exten- 
sion suggested by other comments. The agency 
decided, based on test data, that a 10 percent ex- 
tension would be sufficient to make it easier for 
manufacturers to assure that their vehicles' brak- 
ing systems perform well in both fully loaded and 
lightly loaded conditions. 

The agency considered and rejected the alter- 
native of adopting different test requirements for 
final stage manufacturers or providing final stage 
manufacturers with a longer period of leadtime 
than other manufacturers. Either approach would 
result in a safety standard that was applied on 
the basis of the particular manufacturer of a vehi- 
cle rather than the safety needs of a particular 
vehicle type. The National Traffic and Motor 
Vehicle Safety Act contemplates the application 
of standards based on vehicle type rather than by 
manufacturer. Further, the agency determined 



PART 571; S 105-83-PRE 58 



that the requirements as adopted, including lead- 
time, are appropriate for all manufacturers. Since 
incomplete vehicle manufacturers should not find 
it necessary to place significant new restrictions 
on the use of their chassis as a result of Standard 
105, final stage manufacturers should not require 
any redesign of their vehicles. 

While the standard's requirements have been 
relaxed to reduce certification burdens on final 
stage manufacturers and to make it easier for 
manufacturers to assure that their vehicles' brak- 
ing systems are balanced for both lightly loaded 
and fully loaded conditions, the agency encour- 
ages manufacturers to recognize the safety ad- 
vantages offered by better braking systems and, 
where possible, to produce vehicles which meet 
or exceed the more stringent requirements that 
were proposed. 

A number of more general comments were 
received on the appropriateness of the 8,000 lb. 
GVWR boundary. American Motors/Jeep stated 
that it supported adoption of the 8,000 lb. GVWR 
cutoff as a reasonable first step in addressing the 
brake proportioning difficulties inherent in 
vehicles with a wide weight differential between 
their loaded and unloaded conditions. However, 
the commenter suggested that the agency in- 
vestigate the feasibility of developing new 
criteria that respond directly to the laden to 
unladen ratio regardless of the vehicle's GVWR. 
Other comments, including those of General 
Motors, the Motor Vehicle Manufacturer's 
Association, Wagner Electric and NTEA also sug- 
gested that the agency consider an approach us- 
ing a laden/unladen weight distribution ratio 
criterion. Several of those commenters empha- 
sized that as vehicle downsizing continues, 
vehicles with a GVWR of under 8,000 lbs. will 
have the same balance problems as vehicles of 
8,000 to 10,000 lbs. GVWR. 

The agency recognizes that this may become a 
problem in the future, but only if manufacturers 
seek to hold GVWR constant as they downsize 
their fleets rather than keeping payload constant. 
Since the agency believes payload to be a better 
measure of a vehicle's utility than GVWR, the 
agency encourages manufacturers to keep a con- 
stant payload instead of a constant GVWR as 
they downsize their vehicles. The agency will 
monitor developments in this area. 

A comment submitted by Daimler-Benz stated 



that it saw no justification for an additional 
weight class of 8,000 to 10,000 lbs. GVWR and 
suggested that those vehicles be included with 
vehicles over 10,000 lbs. GVWR. According to 
that commenter, the brake regulations of some 
countries have a 3,500 kilogram (7716 lb.) weight 
limit, and some design characteristics of vehicles 
over 10,000 lbs. GVWR can also be found on 
vehicles with a GVWR of 8,000 lbs. As noted in 
the October 1979 notice, the agency is considering 
establishing more complete brake requirements 
for vehicles with a GVWR of over 10,000 lbs. but 
has not yet done so. This final rule brings the 
more complete requirements of Standard 105 to 
vehicles with a GVWR of 8,000 to 10,000 lbs. and 
includes requirements that are appropriate for all 
vehicles in that class, whatever their design 
characteristics. 

As noted above, the comments concerning ef- 
fectiveness requirements were largely directed 
at the requirements for vehicles with a GVWR of 
8,000 to 10,000 lbs. However, some of the com- 
ments, including those of Chrysler and Wagner 
Electric, were also directed toward the fourth ef- 
fectiveness requirements in general. Both the 
agency's own tests and confidential data submit- 
ted by the manufacturers indicate that recent 
models of almost all vehicles under 8,000 lbs. 
GVWR pass the effectiveness requirements. For 
any vehicles that do not, only minor changes 
would be required. As discussed above, it is 
easier to design braking systems for these 
vehicles than larger vehicles since they do not 
have as wide a weight differential between their 
loaded and unloaded conditions. Moreover, the 
type of work-performing equipment that can 
create center of gravity problems for final stage 
manufacturers is generally installed on vehicles 
with a GVWR of 8,000 lbs. or more. Therefore, no 
changes were made in the requirements as pro- 
posed for vehicles with a GVWR of under 8,000 
lbs. 

Comments submitted by Ford and Chrysler re- 
quested that both second and fourth effectiveness 
tests at 80 mph be eliminated in light of the 55 
mph national speed limit. Ford also noted that ac- 
tions required for fuel economy decrease the max- 
imum speed capability of vehicles. The standard 
is written to require that the 80 mph test be met 
only if vehicles are capable of attaining a speed of 
84 mph. Therefore, vehicles which cannot attain 



PART 571; S 105-83-PRE 59 



that speed need not comply with the 80 mph re- 
quirements. Since many vehicles can attain 
speeds well in excess of 80 mph and some vehicles 
are at times driven at those high speeds, despite 
the 55 mph national speed limit, the agency 
believes that 80 mph requirements are appro- 
priate and in the interest of safety. 

Fade Recovery; Water Recovery 

The October 1979 notice explained that the 
fade and recovery requirements were included to 
assure that a vehicle's braking performance is 
satisfactory when exposed to the high brake 
temperatures caused by prolonged or severe use, 
such as is found in long, downhill driving. The pro- 
posal requires that vehicles be capable of passing 
two successive fade and recovery tests. The 
water recovery requirements assure that a vehi- 
cle's braking system performs adequately after 
immersion in water. 

The comments on these tests were limited to 
the fade and recovery requirements. Chrysler 
stated that the fade tests simulate abuse that is 
rarely, if ever, encountered in actual customer 
service. That commenter stated that the fade 
tests, coupled with the fourth effectiveness re- 
quirements which follow the fade tests, would 
result in braking systems that are biased toward 
the rear brakes. According to Chrysler, rear 
biased brakes would be prone to lock-up in the 
lightly loaded condition. Wagner Electric submit- 
ted a similar comment and suggested that the sec- 
ond fade and recovery test and the fourth effec- 
tiveness test were redundant. That commenter 
suggested that those two tests be eliminated to 
simplify the test procedures of Standard 105. 

The concern that the test requirements would 
result in braking systems biased toward the rear 
brakes was largely discussed in the preceding 
section of this notice. The proposed requirements 
of Standard 105 included both fully loaded and 
lightly loaded tests. The agency concluded, based 
upon its own vehicle tests and on information sub- 
mitted by manufacturers, that the proposed test 
requirements could be met by changes in various 
braking system components. So long as both fully 
loaded and lightly loaded requirements were met, 
the braking system would be properly balanced 
for both fully loaded and lightly loaded condi- 
tions. By extending the fourth effectiveness re- 
quirements by 10 percent for vehicles with a 



GVWR of 8,000 to 10,000 lbs., additional leeway 
was provided to manufacturers in designing their 
braking systems to be properly balanced. As 
noted above, no changes were made in the re- 
quirements applicable to vehicles with a GVWR 
of under 8,000 lbs., since recent models of most of 
those vehicles already pass the effectiveness re- 
quirements. Only minor changes are required for 
those vehicles that do not. 

The two fade tests were designed to produce 
first a mild to moderate fade condition and then a 
more severe fade condition. Light fade occurs in 
vehicles even in low speed applications such as in 
heavy traffic. Moderate to severe fade is a condi- 
tion that may occur when vehicles are used on 
hilly or mountainous roads, especially when 
heavy loads are carried. Far from being redun- 
dant, the second fade test simulates the type of 
fade experienced during long mountain descents. 
The agency has verified that the temperatures 
produced by the test sequence are the same 
temperatures as sometimes experienced during 
long mountain descents. The fade and recovery 
test requirements assure that brakes do not per- 
form abnormally while subject to the heat caused 
by severe use or during the time that the brakes 
are cooling off after severe use. 

The fourth effectiveness test is a complete ef- 
fectiveness test that is conducted after most of 
the other tests, including the fade tests, have 
been completed. This test is included to give an 
overall system evaluation to assure that a brak- 
ing system retains satisfactory characteristics 
related to effectiveness, pedal force, and sen- 
sitivity after exposure to the types of conditions 
simulated during the test sequence. 

A comment submitted by the American Truck- 
ing Associations (ATA) suggested that the pro- 
posed fade requirements are severe enough to 
adversely affect user acceptance in normal serv- 
ice. According to ATA, compromises in such 
things as loss of feel and hard pedal in order to 
achieve greater fade resistance may be neces- 
sary. The comment also suggested that fade 
resistance tests developed in the past may be out- 
dated as vehicles are becoming less powerful. 

The agency tested a number of production 
vehicles before proposing the fade requirements 
and found that almost all of them met the re- 
quirements. The only vehicles tested by the agen- 
cy which appeared to present problems were 



PART 571; S 105-83-PRE 60 



some small imported pickup trucks. Since many 
other vehicles passed the requirements, without 
having problems such as loss of feel or hard 
pedal, it is clear that braking systems can be 
designed to meet the fade requirements without 
having the problems suggested by ATA. Since 
fade tests primarily apply to a vehicle's downhill 
performance, the requirements are appropriate 
for vehicles even if they are less powerful than in 
the past. 

Partial System Failure; Failed 
Power-Assist/Power Units 

Partial system failure requirements were in- 
cluded to ensure that a vehicle's brakes are 
capable of bringing the vehicle to a controlled 
stop in a reasonable distance if a part of the serv- 
ice brake system should fail. Stopping distance 
requirements were also proposed for vehicles 
with failed power-assist or brake power units. 

The October 1979 notice explained that many 
manufacturers currently provide what are called 
split brake systems to provide braking capacity 
in the event of a partial failure. The split system 
consists of two or more brake subsystems, each 
of which is not affected by leakage or failure in 
the other subsystem. Split systems are typically 
used on passenger cars, school buses, light trucks 
and vans. Under the proposed requirements, all 
hydraulic braked vehicles are required to utilize 
a split or redundant brake system. 

Several commenters stated that the stopping 
distances for partial failure and for inoperative 
brake power and power assist units for vehicles 
with a GVWR over 10,000 lbs. are too stringent. 
Daimler-Benz stated that the requirements could 
only be met if the operative braking system has 
an increased capacity. 

In a late submission to the docket, Wagner 
Electric asserted that agency tests substan- 
tiating the capability to meet the partial system 
requirements for vehicles over 10,000 lbs. were 
based on the two most effective of the possible 
partial systems. The commenter stated that no 
data was provided on vertical split systems and 
suggested that the requirements as proposed 
would encourage forms of split systems, such as 
vertical split systems, that would inordinately in- 
crease the level of front brake torque (i.e., make 
the front brakes overly powerful) and contribute 
toward lock-up on icy or wet roads. (A vertical 



split system essentially consists of one sub- 
system that supplies braking power to the front 
brakes and another subsystem that provides 
power to the back brakes. This contrasts with a 
variety of other types of split systems. Some 
horizontal split systems, for example, consist of 
two subsystems that each provide some braking 
power to each wheel. The two types of split 
systems which Wagner Electric's comment sug- 
gested are the most effective are a horizontal 
split and a 1- V2 x V2 split, a system with some of 
the attributes of a horizontal split system.) A 
comment submitted by ATA also suggested that 
the requirements would mandate overly power- 
ful, aggressive front brakes. 

Several commenters suggested that the stop- 
ping distance requirements for vehicles over 
10,000 lbs. GVWR be relaxed. Wagner Electric 
suggested that the requirements currently in ef- 
fect for school buses be adopted. 

The partial system failure and failed power 
assist or brake power unit requirements were 
proposed by the agency after careful analysis of 
its own vehicle test results and of confidential 
data submitted by manufacturers. These data in- 
dicate that many production vehicles already 
meet the proposed requirements. The current 
school bus requirements were issued in 1975 
under a short-term statutory deadline. Analysis 
of current school bus data indicates that many 
school buses already meet the more stringent re- 
quirements proposed by the October 1979 notice. 
As with other stopping distance requirements, 
there is some increment of safety benefit for 
each reduction of stopping distance. When par- 
tial failure of the service brake system occurs or 
brake power or power assist units become in- 
operative, it is important that a vehicle be able to 
stop in a reasonable distance, especially when 
that vehicle has the aggressivity associated with 
a GVWR of over 10,000 lbs. 

In regard to Wagner Electric's comment con- 
cerning vertical split systems, it is true that if 
the subsystem providing power to the rear 
brakes in a vertical split system fails, the sub- 
system providing power to the front brakes 
would be required to meet the stopping distance 
requirements under the standard. Therefore, in 
order to meet this requirement with a vertical 
split system, a vehicle would need relatively 
powerful front brakes. Similar requirements 



PART 571; S 105-83-PRE 61 



have been in effect for vehicles with air brakes 
under Standard 121, and European regulations 
necessitate even more powerful front axle brakes 
without safety problems. 

Moreover, in keeping with the National Traffic 
and Motor Vehicle Safety Act, the requirements 
are written as performance requirements and not 
design requirements. Manufacturers may meet 
the requirements in many different ways and are 
not required to use vertical split systems. Indeed, 
the selection of a means of compliance that poses 
significant safety risks could raise a safety defect 
issue. If Wagner Electric is concerned that ver- 
tical split systems may contribute to lock-up 
when used on some vehicle configurations, the 
manufacturer has the option to use other types of 
split systems, such as horizontal splits, or a 
redundant split system. When one of the subsys- 
tems of a horizontal split system fails, some brak- 
ing power is still provided to each wheel by the 
operative subsystem, so the stopping distances 
do not have to be met solely by the power pro- 
vided to the front wheels. Therefore, the braking 
system does not have to have relatively powerful 
front brakes in order to meet the requirements. 
This would also be true for some other types of 
split systems and for redundant systems. 

Wagner Electric also stated that the 150 lb. 
maximum pedal force specified for the re- 
quirements is too low and might result in overly 
sensitive brakes. That company suggested that a 
200 lb. pedal force be adopted. 

An analysis of the data referred to above in- 
dicates that many vehicles on the road already 
meet this requirement, without experiencing 
problems of oversensitivity. While Wagner Elec- 
tric suggests in its comment that even a small 
person can reach a 200 lb. pedal effort, the agency 
has found that small females have difficulty even 
applying forces of less than 150 lbs. 

Moreover, when a driver is used to applying 
very little force to bring a vehicle to a stop, the 
driver is likely to believe that the braking system 
has failed entirely, rather than only partially, 
if the driver applies maximum force and cannot 
feel the vehicle braking. Reports of "no brakes" 
are sometimes given in accident reports where 
only a partial failure has occurred. Therefore, 
it is important that a vehicle's braking sys- 
tem respond noticeably when a driver is apply- 
ing significant force in a partial failure or 



failed power assist or brake power unit situation. 

A comment submitted by the Metropolitan 
Transit Agency of Dade County, Florida, called 
for lower pedal force requirements. That com- 
menter cited the difficulty smaller drivers have 
in bringing a large bus to a stop after loss of 
vacuum. In establishing the 150 lb. pedal force, 
the agency took account of both the need to 
establish a level of pedal force appropriate for 
smaller drivers and to keep it high enough that 
brakes will not be oversensitive in ordinary use. 
That commenter also suggested that the agency 
establish requirements for vacuum reserve. The 
agency included optional procedures in Standard 
105 that encourage manufacturers to include 
vacuum reserves by permitting slightly longer 
stopping distances in the no power tests if the 
vehicle has the capability of making several stops 
in consecutive order with gradually decreasing 
capabilities. The agency recognizes the safety ad- 
vantages offered by vacuum reserves, but has 
not, as of yet, proposed that they be required. 

A comment submitted by the Recreation Vehi- 
cle Industry Association (RVIA) requested that 
the test procedures for vehicles with a GVWR of 
over 10,000 lbs. be changed to require less stops 
and snubs to condition the brakes. The agency 
declines to make this change since a significant 
number of stops and snubs is required in order 
that a braking system's capability be tested in a 
"worn-in" condition. 

Equipment Integrity 

Comments on the requirements concerning 
equipment integrity were primarily limited to the 
spile stop requirements. RVIA suggested that 
the spike stop test requirements are inappro- 
priate for motor homes. According to RVIA, it is 
unaware of a single case where a weakness that 
the spike stop test would uncover has ever been 
found in a motor home. 

The spike stop test requirements were devel- 
oped to determine the structural integrity of a 
vehicle's braking system. Vehicles must be 
capable of making several very sudden stops 
without loss of brake system structural integrity. 
Virtually all types of vehicles, including motor 
homes, are at times subjected to the abuse caused 
by very sudden stops. If the vehicle's braking 
system loses its structural integrity during such 
stops, serious accidents could result. 



PART 571; S 105-83-PRE 62 



Parking Brakes 

The October 1979 notice proposed parking 
brake performance requirements designed to en- 
sure that vehicles have adequate grade holding 
performance. Under the proposal, vehicles with a 
GVWR of 10,000 lbs. or less are to meet these re- 
quirements on a grade of 30 percent, when a max- 
imum force of 90 lbs. is applied to hand-operated 
parking brake systems and 125 lbs. is applied to 
foot-operated parking brake systems. While no 
comments were received that were specifically 
opposed to the establishment of parking brake re- 
quirements for light trucks, several submissions 
did comment on the appropriateness of the 30 
percent gradient and the maximum force re- 
quirements. 

The Japan Automobile Manufacturers Associa- 
tion and Toyo Kogyo stated that a 30 percent gra- 
dient is too stringent. According to those com- 
ments, some vehicles have difficulty climbing a 30 
percent grade when fully loaded. They requested 
that a gradient of 18 percent be adopted, stating 
that European and Australian safety standards 
incorporate that requirement. 

The 30 percent gradient requirement, which is 
the same as that in effect for passenger cars and 
school buses with a GVWR of 10,000 lbs. or less, 
represents a degree of steepness that is found on 
roads in some parts of the United States. While 
the agency is unaware of any light trucks that 
cannot climb a 30 percent grade, even a vehicle 
that has difficulty climbing a 30 percent grade 
may on occasion be parked on such a steep hill. 
Moreover, recognizing the dangers inherent if a 
vehicle's grade holding performance is inade- 
quate, the agency established the requirements 
with a view toward providing a margin of safety 
for parking brake systems. The safety margin 
will prevent accidents from occurring when 
vehicles are parked on more commonly found 
grades, in some instances, where parking brake 
systems have deteriorated over time or are im- 
properly adjusted. It is also noted that although 
European regulations have only an 18 percent 
grade-holding requirement, those regulations 
also require a dynamic stopping performance test 
using the parking brake. 

Several commenters stated that the maximum 
force requirements proposed by the standard for 
vehicles with a GVWR of 10,000 lbs. or less are 



too stringent. Those commenters suggesting 
changes requested either that European re- 
quirements be followed (said to be 132 lbs. for 
hand-operated systems) or that current re- 
quirements for school buses be followed (125 lbs. 
for hand-operated systems and 150 lbs. for foot- 
operated systems). 

The 90 lb. and 125 lb. requirements proposed 
by the notice are the same as those in effect for 
passenger cars. They were chosen by the agency 
as the maximum force requirements that are ap- 
propriate for small females. Since small females 
may be expected to drive light trucks, it is ap- 
propriate to require that parking brake systems 
be designed with their needs in mind. Moreover, 
the agency established the 90 lb. and 125 lb. re- 
quirements with a recognition that some parking 
brake systems are located in positions within the 
vehicle which are awkward for drivers to reach. 
The 90 lb. and 125 lb. requirements therefore pro- 
vide a margin of safety for instances where 
drivers have difficulty applying adequate force to 
parking brake systems because of their location. 

As with the other requirements of the pro- 
posal, the agency established the parking brake 
requirements after conducting tests on produc- 
tion vehicles. Neither the agency's test results or 
any comments submitted indicate that manufac- 
turers will have difficulty meeting the parking 
brake requirements. 

Costs and Benefits 

The agency has considered the economic and 
other impacts of this final rule and determined 
that this rule is not significant within the mean- 
ing of Executive Order 12221 and the Department 
of Transportation's policies and procedures im- 
plementing that order. The agency's assessment 
of the benefits and economic consequences of this 
final rule are contained in a regulatory evaluation 
that has been placed in the docket for this rule- 
making. Copies of that regulatory evaluation can 
be obtained by writing NHTSA's docket section, 
at the address given in the beginning of this 
notice. 

The October 1979 notice explained that a regu- 
latory evaluation had been prepared before issu- 
ing the notice and had been included in the 
docket. A number of comments were received on 
the costs and benefits of the proposed re- 
quirements. 



PART 571; S 105-83-PRE 63 



Ford stated that although its cost analyses 
were not complete, it had sufficient information 
to indicate that the proposed requirements 
would affect a greater number of Ford products 
and cost considerably more than the agency had 
estimated. Chrysler stated that the requirements 
would necessitate the redesign of the parking 
brake systems on all of its light trucks and re- 
quire some degree of revision to master 
cylinders, brake boosters, and/or foundation 
brakes on 80 to 90 percent of its light trucks. 
That company also indicated that it would find it 
necessary to engage in considerably more testing 
than estimated by the agency in order to meet 
the proposed requirements. 

Both Ford and Chrysler suggested that several 
requirements be relaxed in order to reduce the 
costs of the proposed standard. Ford requested 
that first, second and fourth effectiveness test 
stopping distances be relaxed for all vehicles and 
that third effectivenss test stopping distances be 
relaxed for vehicles with a GVWR of 8,000 to 
10,000 lbs. Foi-d also requested that the stopping 
distance requirements for the failed system and 
spike stop check tests be relaxed and that the 
maximum parking brake force requirements be 
changed from 125 lbs. to 150 lbs. Chrysler asked 
that fourth effectiveness test stopping distances 
be extended by 16 percent and that the max- 
imum parking brake force requirements be 
changed from 125 lbs. to 150 lbs. 

General Motors stated that while it supported 
NHTSA action to require split service brake 
systems on vehicles over 10,000 lbs. GVWR, a 
considerably larger number of those vehicles 
would require changes than estimated by the 
agency. According to GM, optional split service 
brake systems were purchased on only two per- 
cent of its hydraulic braked heavy-duty vehicles 
in model year 1979. 

In order to aid in developing its cost estimates, 
the agency enlisted an outside contractor before 
issuing the October 1979 notice to conduct an in- 
dependent assessment of the costs that would be 
involved. A report prepared by the IIT Research 
Institute (IITRI), which was included in the 
docket, substantially verified the cost estimates 
made by NHTSA, with one exception. 

As the regulatory evaluation explained, 
estimates on the light truck brake system costs 
differed, reflecting the different methodologies 



used by IITRI and NHTSA. Since NHTSA's 
estimates were based on actual test results and 
confidential data submitted by the manufac- 
turers, which were unavailable to IITRI, the 
regulatory evaluation used NHTSA figures for 
light truck brake system costs. IITRI figures 
were used for development/compliance test costs 
and cost estimates for medium and heavy duty 
trucks. 

A revised regulatory evaluation, which has 
been placed in the docket, was prepared by the 
agency to accompany the issuance of this final 
rule. Revisions were made in the regulatory 
evaluation to reflect the latest information 
available to the agency. 

The comments by Ford and Chrysler were dif- 
ficult to evaluate since they gave only general- 
ized bases for their assertions that a greater 
number of vehicles would be affected by the 
standard than estimated by the agency. While 
those commenters cited some additional braking 
system components that might require changes, 
they did not specify which vehicles would require 
the changes or indicate what the costs of those 
changes would be. 

For example, while Chrysler asserted that the 
requirements would necessitate the redesign of 
the parking brake systems on all of its light 
trucks, it did not indicate its basis for believing 
that substantially more of its light trucks would 
require upgrading of their parking brake 
systems than estimated by the agency. Nor did it 
indicate what changes would be required or the 
costs of those changes. Ford stated that prelimi- 
nary test results indicate that the proposal would 
necessitate for some models, in addition to those 
changes assumed by the agency to be required, 
the addition of hydraulic boosters or larger 
hydraulic boosters and revisions to brake pedals, 
power steering pumps, hoses and tires. Ford did 
not indicate the nature of the preliminary test 
data it was relying upon. Nor did that commenter 
specify what models would require additional 
changes or indicate the costs of those changes. 
Also, while Ford requested numerous changes in 
the proposed requirements, it did not attempt to 
support the specific changes it requested. 

In light of the agency's own detailed evalua- 
tion of the changes made necessary by the re- 
quirements and of the costs of those changes, 
which was based upon test data and manufac- 



PART 571; S 105-83-PRE 64 



turer-supplied information, as well as the inde- 
pendent assessment made by IITRI, the agency 
continues to believe that its cost estimates are 
correct, with one exception noted below. 

The agency did change the regulatory evalua- 
tion's estimate of the number of vehicles with a 
GVWR over 10,000 lbs. requiring split brake 
systems. The agency had anticipated that a 
greater percentage of those vehicles would be 
purchased with optional split brake systems. 
While the number of vehicles affected by that re- 
quirement is greater than originally estimated 
by the agency, the cost per vehicle remains the 
same, and the agency believes the requirements 
to be fully justified by the benefits that will 
accrue. 

Other comments that were received concern- 
ing costs related to costs of developing anti-lock 
or similar devices, such as brake system pressure 
modifiers, and cost that would be borne by final 
stage manufacturers. As explained fully above in 
the portion of this notice entitled "Effectiveness 
Requirements," manufacturers will not find it 
necessary to develop anti-lock or similar devices, 
nor will final stage manufacturers in most cases 
have any costs as a result of the standard. In- 
stead, final stage manufacturers will ordinarily 
be able to rely on the incomplete vehicle 
manufacturer's certification of the braking 
system. 

The October 1979 notice explained that the 
proposal was a continuation of prior NHTSA 
rulemaking on Standard 105. While the extension 
of Standard 105 to trucks, buses and MPV's had 
proceeded to the adoption of a final rule, that ex- 
tension was indefinitely delayed in April 1975 
because the agency had determined that 
although the benefits of the rule would be 
substantial, the costs of the standard, particu- 
larly for heavy trucks, warranted delaying the 
standard. See 40 FR 18411, April 28, 1975. 

Manufacturers have made a number of signifi- 
cant improvements in their braking systems 
since that time on a voluntary basis, largely 
following the requirements and test procedures 
of the delayed final rule. Because of those im- 
provements, as well as some changes made in the 
requirements by the agency, the costs of the 
standard today are only a small fraction of what 
they would have been in 1975. 

The April 1975 notice stated that manufac- 



turers had submitted costs for light to medium 
duty trucks that ranged from $54 to $775 per unit 
(depending on model configuration) to attain com- 
pliance with the standard. The agency compared 
those figures with independently gathered de- 
tailed cost information and substantiated that 
the manufacturers' estimates were accurate. In 
contrast to those figures, the agency today 
estimates that the average cost per domestic 
light truck, bus, or MPV with a GVWR of 10,000 
lbs. or less is only $2.71, or about $21.24 for each 
vehicle that needs to be upgraded in braking 
system performance. The costs for meeting the 
partial failure and warning indicator re- 
quirements for medium and heavy trucks (over 
10,000 lbs. GVWR) are estimated to be about $54 
per vehicle. The total costs of meeting the stand- 
ard's requirements for all trucks, buses and 
MPV's are estimated to be under $18 million. 

As explained elsewhere in this notice, the 
regulatory evaluation, and the October 1979 
notice, the agency carefully evaluated the costs 
and benefits of the proposed requirements. In 
analyzing costs, the agency estimated how the re- 
quirements would affect each manufacturer on a 
model-by-model basis. In light of this detailed 
analyis and evaluation, the agency declined to 
relax particular requirements on the sole ground 
that they would result in some costs to manufac- 
turers. 

A number of comments were also received that 
related to the benefits of the standard. Ford 
stated that the proposed requirements have not 
been justified as being the minimum necessary to 
provide safe operation of the affected vehicles. 
That commenter stated that the agency had not 
provided evidence that the levels of braking per- 
formance of today's vehicles are causative fac- 
tors in the accidents involving those vehicles. 

Ford also stated that the estimate of benefits 
presented in the agency's regulatory evaluation 
is based on inappropriate data and incomplete 
analysis. In particular, that commenter stated 
that a study by the Institute for Research in 
Public Safety (IRPS) that was cited by the 
regulatory evaluation does not support the con- 
clusion that a 5 to 10 percent reduction in ac- 
cidents could be obtained by a 5 percent shorten- 
ing of stopping distances. That study was based 
on a sample of skidding accidents, and the finding 
was related to the benefits that would accrue if 



PART 571; S 105-83-PRE 65 



vehicles were equipped with anti-lock braking 
systems. According to Ford, that finding does not 
relate to the effect on accidents that would be at- 
tributable to the implementation of the proposed 
requirements, since the requirements do not an- 
ticipate the introduction of anti-lock braking 
systems. That company also asserted that the 
relationship between measured vehicle param- 
eters such as specific stopping distances derived 
under specified test conditions and the safety ef- 
fectiveness of the same vehicle in customer serv- 
ice has yet to be established. 

A similar comment was submitted by NTEA. 
That commenter stated that by failing to demon- 
strate why an increase in light truck accident 
fatalities has occurred or that the proposed stand- 
ard will in any way reduce those fatalities, the 
NHTSA data are seriously deficient. NTEA also 
stated that since the requirements will affect only 
17 percent of the vehicles subject to the standard, 
NHTSA is obligated to identify that 17 percent 
segment as the cause of the safety problem. (As a 
result of the agency revising its estimate of the 
number of vehicles with a GVWR over 10,000 lbs. 
requiring the addition of split service brake 
systems, discussed above, the percentage of 
vehicles requiring changes as a result of the 
standard is now estimated to be about 20 
percent.) 

The October 1979 notice explained that in car- 
rying out the mandate of the National Traffic and 
Motor Vehicle Safety Act to issue vehicle safety 
standards to protect the public against unreason- 
able risk of vehicle accidents and of death or in- 
jury occurring as a result of such accidents, the 
agency is confronted with inherent problems that 
limit the degree of certainty and precision 
achievable in estimating the effectiveness and 
therefore benefits of proposed standards. While 
engineering and accident analyses can clearly 
demonstrate that certain vehicle improvements 
will facilitate the performance of the driver's task 
and thereby improve safety, it is virtually im- 
possible to isolate individual factors to arrive at 
precise and certain conclusions about the quan- 
tified benefits that will accrue. 

Given the duty to act in the area of accident 
avoidance notwithstanding an inherent measure 
of imprecision and uncertainty, the agency has 
developed and issued accident avoidance stand- 
ards while attempting within its capabilities to 



quantify the benefits of the standards and limit 
the uncertainty. The extension of Standard 105 is 
no different, and, given the inevitable residual 
uncertainty, the decisionmaking regarding the 
precise requirements rests in part on policy judg- 
ment. 

The braking system of a vehicle clearly pro- 
vides its most important accident avoidance 
capability. Common sense, as well as basic traffic 
theory, indicate that a vehicle with a shorter stop- 
ping distance capability will be safer than the 
same vehicle with a longer stopping distance 
capability, assuming that other parameters such 
as vehicle stability are held constant. Also, as 
noted above, since light trucks, buses, and MPV's 
share the same traffic flow as passenger cars, 
they should ideally have the same stopping 
distance capability. 

As fully explained above, the agency carefully 
evaluated the costs of improving braking systems 
for light trucks, buses and MPV's and proposed 
requirements that, in its judgment, were eco- 
nomical. In recognition of the costs and problems 
associated with anti-lock or similar devices, the 
agency proposed requirements that could be met, 
where upgrading was required, by simple, state- 
of-the-art changes to the types of braking 
systems in use. Since braking ability is an ex- 
tremely important safety factor and stopping 
distances can economically be made significantly 
shorter for light trucks, buses, and MPV's, the 
agency believes that the braking ability of those 
vehicles creates an unnecessary risk. 

Because available accident data and studies are 
limited, it is very difficult to make estimates as to 
the precise benefits that will result from improv- 
ing a vehicle's accident avoidance capability. The 
best information available to the agency in 
estimating the benefits resulting from improved 
stopping distances was the IRPS study, which 
was based on a survey of skidding accidents. Skid- 
ding accidents are useful for analysis because 
they leave physical evidence indicating the brak- 
ing distance of a vehicle prior to impact. Based 
upon that study, the agency concluded that a 5 to 
10 percent reduction of accidents could be ob- 
tained by a 5 percent shortening of stopping 
distances. 

The proposed requirements would result in a 
reduction of skidding accidents, despite the fact 
that anti-lock or similar devices are not con- 



PART 571; S 105-83-PRE 66 



templated, since some vehicles would have their 
braking balance improved. Also, with better 
braking capability, drivers might be less prone to 
applying their brakes in a manner that would 
result in skids. While the IRPS data may not be 
ideal, since it looked at some types of skidding 
accidents that would not be prevented by the re- 
quirements and did not look at some accidents 
that would be prevented (i.e., those that do not 
leave skid marks), the agency believes that it 
does provide evidence that is useful in analyzing 
all accidents where braking is attempted. 

The 105 test sequence was designed to simulate 
real world conditions. A vehicle's braking system 
is tested, for example, in new and broken-in condi- 
tions, at various speeds, while the vehicle is fully 
and lightly loaded, under varying conditions of 
fade, and under partial failure and failed power. 
Thus, the test does relate to performance in 
customer service. 

In deciding to propose the extension of Stand- 
ard 105 to light trucks, buses and MPV's, the 
agency was very concerned about the recent in- 
crease in light truck fatalities. However, the exten- 
sion is directed at all accidents and not merely at 
the increase in accidents as suggested by NTEA. 

As noted above, manufacturers have largely 
improved the braking performance of many of the 
vehicles subject to this standard since the final 
rule was delayed in 1975. Because of these im- 
provements, changes will be required in only 
about 20 percent of the vehicles subject to the 
standard. The only effect on the other 80 percent 
of vehicles is that manufacturers will not be able 
to reduce the performance of those vehicles' ex- 
isting braking systems. 

The agency believes it appropriate to require 
that manufacturers maintain the current level of 
braking performance for that 80 percent segment 
of vehicles. In the 1960's, for example, stopping 
distances of passenger cars lengthened as a result 
of increased weight. Today, the agency is con- 
cerned that manufacturers might reduce the 
braking ability of their vehicles as part of an ef- 
fort to improve fuel economy. Since some braking 
system components are relatively heavy, the 
braking system is a prime target for weight 
reduction. The agency believes braking ability to 
be such an important safety factor that it should 
not be compromised by efforts to improve fuel 
economy. 



Because of the limitations of available accident 
data, it is difficult and sometimes impossible to 
use available accident data to determine the acci- 
dent rates of particular vehicle types. As noted 
above, the agency believes the braking ability of 
those vehicles requiring upgrading of their brak- 
ing systems to create an unreasonable risk, since 
that ability can economically be significantly im- 
proved. 

Miscellaneous Comments 

The Japan Automobile Manufacturers Associa- 
tion stated that separate requirements should be 
applicable to vehicles used for passengers and 
those used for cargo. That request is similar to 
ones received during other rulemaking pro- 
ceedings to establish separate requirements for 
commercial applications. 

The National Traffic and Motor Vehicle Safety 
Act contemplates the application of standards 
based on vehicle type instead of vehicle use. Bas- 
ing a standard on vehicle use would present dif- 
ficult enforcement problems. It would also place a 
manufacturer in the difficult position of having to 
assess in advance the potential future use of the 
vehicle. Further, basing standards on vehicle use 
does not recognize that a vehicle may have two or 
more uses during its lifetime. Therefore, the 
agency has declined to establish separate re- 
quirements based upon vehicle use. 

The Japan Automobile Manufacturers Associa- 
tion also requested that all vehicles with a GVWR 
over 10,000 lbs., other than school buses, be in- 
cluded in Standard 130 under contemplation. 
Daimler-Benz also requested that vehicles over 
10,000 lbs. be included in one standard, whether 
they have air brakes or hydraulic brakes. Based 
upon the differences between air brake systems 
and hydraulic brake systems, the agency has 
issued separate standards for the two types of 
braking systems. Standard 121 currently applies 
to air braked vehicles and Standard 105 to 
hydraulic braked vehicles. 

The agency has issued an advance notice of pro- 
posed rulemaking for a new standard to apply to 
heavy duty brake systems. Standard 130, which 
addressed issues for which rulemaking is at least 
several years away. See 45 FR 13155, February 
28, 1980. A notice of proposed rulemaking, with 
opportunity to comment, would be issued if the 
agency decides to proceed with that standard. 



PART 571; S 105-83-PRE 67 



General Motors stated that the proposed re- 
quirements of Standard 105 may not be appro- 
priate for electric vehicles which are under 
development. Since these vehicles are still in the 
development stage, the agency is unable to 
establish at this time what types of changes, if 
any, would be appropriate for electric vehicles. 
The agency will consider the need for different 
requirements for electric vehicles when more in- 
formation is available as to what characteristics 
those vehicles will have. 

Wagner Electric requested that the weight 
permitted for driver and instrumentation on 
vehicles with a GVWR of 10,000 lbs. or less for the 
lightly loaded tests be increased from 300 lbs. to 
400 lbs. to permit the use of more recording 
equipment. Since the lightly loaded tests measure 
the braking ability of a vehicle while unloaded, it 
is desirable to keep the weight as low as possible. 
However, after evaluating the types of in- 
strumentation that are used to certify compliance 
with Standard 105, the agency agrees that in- 
creasing the weight allowance for driver and in- 
strumentation from 300 lbs. to 400 lbs. for 
vehicles with a GVWR of 10,000 lbs. or less will 
allow the use of additional types of instrumenta- 
tion that will be useful in evaluating the perform- 
ance of a vehicle's braking system. Moreover, the 
agency has determined that the slight increase in 
weight will not adversely affect the results of the 
lightly loaded tests. 

One commenter suggested that the standard's 
requirements might have an adverse effect on 
tire manufacturers, since tires are an important 
parameter in complying with the standard and 
manufacturers would not have the time, funds or 
facilities to test every kind of tire. Manufacturers 
will not be required to test all kinds of tires, since 
they purchase tires according to specifications. 
Normal production tires were used in all tests 
relied on by the agency in establising the stand- 
ard's requirements. The standard has been in ef- 



fect for several years for passenger cars and 
school buses without adverse effects on tire 
manufacturers. 

Leadtime 

Numerous comments were received on the pro- 
posed effective date of the requirements. The 
agency evaluated those comments and agrees 
with a number of them that a minimum of 2 years 
leadtime is appropriate. The effective date of the 
standard was changed to September 1, 1983, 
which gives a leadtime well in excess of 2 years 
and corresponds with the start of a new model 
year. 

Chrysler stated that it required a leadtime of 
30 months if its recommendations were adopted 
and 42 months if its recommendations were not 
adopted. The extra 12 months beyond 30 months 
were said to be needed to develop load-sensing or 
deceleration-sensing proportioning valves. As ex- 
plained fully in this notice, no manufacturer will 
be required to develop anti-lock or similar devices 
in order to be able to comply with the standard's 
requirements. The effective date of this final rule 
gives a leadtime of approximately 30 months. 

The principal authors of this notice are George 
L. Parker, Office of Vehicle Safety Standards, and 
J. Edward Glancy, Office of Chief Counsel. 

In consideration of the foregoing, §571.105, 
Chapter V of Title 49, Code of Federal Regula- 
tions, is amended accordingly. 

Issued Oh December 22, 1980. 



Joan Claybrook 
Administrator 

46 FR 55 
January 2, 1981 



PART 571; S 105-83-PRE 68 



PREAMBLE TO AN AMENDMENT TO 
FEDERAL MOTOR VEHICLE SAFETY STANDARD NO. 105 

Hydraulic Brake Systems 

(Docket No. 70-27; Notice 23) 



ACTION: Final rule; response to petitions 
for reconsideration. 

SUMMARY: This notice responds to three 
petitions for reconsideration concerning the 
amendment extending Standard No. 105, 
Hydraulic Brake Systems, to trucks, buses, 
and multipurpose passenger vehicles 
(MPV's). The amendment also upgraded the 
standard's requirements for school buses. In 
response to one of the petitions, the agency 
has changed the parking brake gradient 
requirement from 30 percent to 20 percent 
for trucks, buses (other than school buses) 
and MPV's with a GVWR of 10,000 pounds or 
less. The agency will shortly propose a 
conforming amendment to make the same 
change for school buses with a GVWR of 
10,000 pounds or less. 

DATES: This amendment is effective 
September 1, 1983. That is the same effective 
date as for the January 1981 final rule 
extending Standard No. 105 to trucks, buses 
and MPV's. 

ADDRESS: Petitions for reconsideration 
should refer to the docket number and be 
submitted to: Docket Section, Room 5109, 400 
Seventh Street, S.W., Washington, D.C. 
20590. 

SUPPLEMENTARY INFORMATION: On 

January 2, 1981, the NHTSA published in the 
Federal Register (46 F.R. 55) a final rule 
amending Standard No. 105, Hydraulic Brake 
Systems. Prior to that time, the standard 



applied to passenger cars and school buses 
only. The amendment extended the standard's 
applicability on a general basis (with some 
modifications) to trucks, all types of buses, 
and multipurpose passenger vehicles (MPV's) 
with a gross vehicle weight rating (GVWR) of 
10,000 pounds or less. (These vehicles are 
collectively referred to as LTM's.) Several 
requirements were also extended to trucks, 
buses and MPV's with a GVWR greater than 
10,000 pounds. In addition, the standard's 
requirements for school buses were upgraded. 
Petitions for reconsideration were filed 
with the agency by Chrysler, Ford and the 
Brake System Parts Manufacturers Council, 
all of which dealt almost entirely with the 
requirements applicable to vehicles with a 
GVWR of 10,000 pounds or less. Of the three 
petitions, Chrysler's was the only one that 
raised any technical issues associated with 
compliance with the amendment. All three 
petitions challenged the amendment on the 
bases of safety need and/or costs and 
benefits. After carefully evaluating those 
petitions, the agency decided to modify the 
parking brake requirements in response to 
Chrysler's petition. To the extent set forth 
below, Chrysler's petition is granted. 
Otherwise, Chrysler's petition and the other 
two petitions are denied. 

Parking Brake Requirements 

Standard No. 105 includes requirements 
for both a vehicle's service brake system and 
its parking brake. These two systems are 
related in that the parking brake uses major 



PART 571; S 105-83-PRE 69 



components of the service brake system, 
including the brake shoes and brake drums. 
The final rule's parking brake requirements 
specified that various performance tests be 
met when a vehicle is parked on a 30 percent 
grade and a maximum force of 90 pounds is 
applied to hand-operated parking brake 
systems and 125 pounds is applied to foot- 
operated parking brake systems. 

Chrysler's petition for reconsideration 
stated that the parking brake effort limits 
would cause a major redesign of most of its 
brake systems. According to that company, 
such redesign would waste scarce resources 
and be inflationary in the absence of 
demonstrated benefits. 

The agency contacted Chrysler to obtain 
clarification of that company's assertions. 
The agency requested information about the 
nature of the changes needed to meet the 
parking brake requirements and the costs of 
those changes, as well as data substantiating 
those needs. Chrysler indicated that all of its 
parking brake systems would require changes 
in order to meet the parking brake 
requirements. Many vehicles were said to 
require a major redesign, including new 
actuating pedals and supporting structures, 
low friction cables with new guides, new 
parking brake lever arms within the rear 
brake drums, and new shoes and linings. 

Chrysler's assertions were substantiated 
by test data. Chrysler ran a series of parking 
brake tests on a cross-section of its light 
trucks on both a 32 percent grade and a 20 
percent grade. (The 32 percent grade was 
used because it was the grade closest to 30 
percent that Chrysler had available.) Of nine 
vehicles tested on the 32 percent grade, only 
one passed the parking brake tests. That 
vehicle passed by a margin generally 
considered to be insufficient to assure that 
other vehicles of the same type would pass 
the tests. 

In addition to the information received 
from Chrysler, the agency received new data 
from agency-sponsored tests that were 
conducted for purposes unrelated to this 
rulemaking. Three Chrysler LTM's were 
among the vehicles tested. While the tests 
were limited in number, their results 



confirmed the information supplied by 
Chrysler. Both the data submitted by 
Chrysler and the test results received from 
the agency-sponsored tests have been placed 
in the docket. 

The agency evaluated Chrysler's assertions 
in light of the test data received. Based upon 
that data, the agency has concluded that its 
Regulatory Evaluation underestimated the 
costs of the parking brake requirements for 
Chrysler. Because this conclusion is based on 
actual test results, it is more reliable than the 
original conclusions made in the Regulatory 
Evaluation. Those earlier conclusions were 
largely based on engineering analysis, which 
is generally less reliable than actual testing. 
While they were also based on confidential 
information received from manufacturers, 
the agency had received less information 
from Chrysler than from other companies. 

The Regulatory Evaluation estimated that 
10 percent of Chrysler's LTM's would require 
changes in order to meet the parking brake 
requirements, at an average cost of $10.00 
per vehicle needing changes. The agency now 
estimates that virtually all of Chrysler's 
LTM's would require changes in order to 
meet the parking brake requirements as 
issued. Many of Chrysler's LTM's would 
require a minor redesign with the types of 
changes indicated by Chrysler and listed 
above. Other vehicles would require a minor 
redesign, with such changes as longer 
actuating pedals, rerouted cables, and new 
parking brake lever arms within the rear 
brake drums. 

Chrysler did not provide information about 
the costs of the changes needed to meet the 
parking brake requirements. The agency 
estimates that the cost per vehicle requiring 
a major redesign would be $17.50, while the 
cost per vehicle requiring a minor redesign 
would be $6.00. These estimates are based on 
the types of changes needed for a major 
redesign and a minor redesign, discussed 
above. The agency used brake system 
component costs contained in a report 
prepared by the IIT Research Institute under 
contract to the agency, for guidance in 
preparing its estimates. That report, which 
was issued in 1979, was included in the docket 



PART 571; S 105-83-PRE 70 



at the time the notice of proposed rulemaking 
was issued. 

In response to Chrysler's petition for 
reconsideration, the agency reevaluated 
Standard No. 105's parking brake requirements 
in light of the higher costs that it recognizes 
would result from those requirements. In 
reevaluating the requirements the agency 
analyzed two issues: the appropriateness of 
the parking brake effort limits and the 30 
percent gradient. Concerns about both of 
these issues were raised by several 
commenters in response to the notice of 
proposed rulemaking. 

While the parking brake effort limit and 
gradient requirements address different 
issues from the point of view of motor vehicle 
safety, in practice the two requirements are 
closely related. Over a certain range of both 
force and gradient, a given parking brake will 
hold a vehicle on increasingly steep gradients 
as increasingly greater force is applied to the 
brake. Thus, a given parking brake design 
may be able to meet either a more stringent 
parking brake effort limit (i.e., a limit 
requiring that less force be used) or a steeper 
gradient, but not both. 

The agency has concluded, in light of the 
lack of significant safety need for a gradient 
requirement as stringent as 30 degrees and 
the increased costs that would result from 
the parking brake requirements, that the 
parking brake gradient requirement should 
be changed from 30 percent down to 20 
percent with retention of the parking brake 
effort limits. As explained below, this change 
will substantially reduce the costs of the 
parking brake requirements with only a 
minimal impact on benefits. Also, the change 
may promote international harmonization of 
safety standards. Consideration is currently 
being given in Europe to changing its 
standard to incorporate a 20 percent gradient 
requirement instead of an 18 percent 
gradient. 

The preamble to the final rule explained 
that two commenters had indicated that they 
believed the 30 percent gradient to be too 
stringent. Those commenters requested that 
an 18 percent gradient be adopted, noting 
that European and Australian safety 



standards incorporate that gradient. The 
agency declined to adopt a less stringent 
gradient at that time, noting that 30 percent 
gradients do exist in some parts of the United 
States and that the requirement provided a 
margin of safety where parking brake 
systems have deteriorated over time or are 
improperly adjusted. Even at that time, the 
agency recognized that any benefits of that 
particular requirement would be relatively 
small. Roads with a gradient as steep as 30 
percent exist in only a few parts of the 
country. Therefore, only a small number of 
vehicles affected by this standard would ever 
encounter such roads. 

The agency does not believe that the large 
numbers of vehicles affected by the standard 
should be required to meet this particular 
requirement which would only be of any 
possible benefit for a very small number of 
vehicles. 

The agency declined to change the parking 
brake effort requirements because they were 
chosen as the maximum force requirements 
that are appropriate for small females. Those 
requirements, a maximum force of 90 pounds 
for hand-operated parking brake systems and 
125 pounds for foot-operated parking brake 
systems, are the same as those in effect for 
passenger cars. Chrysler's comment on the 
notice of proposed rulemaking had asked that 
they be changed to 125 pounds and 150 
pounds, respectively. Those limits represent 
the parking brake effort requirements that 
have been in effect for school buses for 
several years. Research studies indicate, 
however, that between 20 and 50 percent of 
the female driving population do not have 
enough strength to exert the maximum pedal 
efforts that have been permitted for school 
buses. It is appropriate to require that 
parking brake systems be designed with the 
needs of the driving population in mind. The 
90 pound and 125 pound limits will cut the 
above percentages in half, i.e., only 10 
percent to 25 percent of the females may lack 
sufficient strength. 

The new parking brake effort limits apply 
to all LTM's, including school buses (with a 
GVWR of 10,000 pounds or less). As noted 
above, school buses were subject to Standard 



PART 571; S 105-83-PRE 71 



No. 105 before the January 1981 final rule 
was issued. The parking brake requirements 
for school buses with a GVWR over 10,000 
pounds, which specify both a 20 percent 
gradient and the less stringent effort limit, 
were not changed by either the Jariiiary 1981 
final rule or this amendment. However, the 
January 1981 final rule did change the 
standard's parking brake requirements for 
school buses with a GVWR of 10,000 pounds 
or less to include the new more stringent 
effort limit. The agency had not proposed 
changing the gradient requirement, which 
remained at 30 percent. 

As a conforming amendment, the agency 
will shortly propose to change the gradient 
requirement for school buses with a GVWR 
of 10,000 pounds or less from 30 percent to 20 
percent. The purpose of that change would be 
to make the parking brake requirements for 
those school buses the same as for other 
LTM's. The agency believes that change 
should be made primarily because school 
buses are constructed on the same chassis, 
including parking brakes, as other LTM's. 
Different parking brake requirements for 
school buses could either limit which chassis 
could be used for school buses or require.that 
new parking brake systems be specifically 
designed and installed on some of those 
chassis used for school buses. In light of the 
more stringent parking brake effort limits 
and the relationship between force and the 
steepness of gradient on which a parking 
brake will hold a vehicle, the agency does not 
believe that current school bus parking 
brakes will be significantly altered as a result 
of the less stringent gradient requirement. 

The agency has determined that significant 
cost savings will result from changing the 
gradient requirement for all LTM's. With a 
30 percent gradient requirement, Chrysler 
would be required to complete major 
redesigns of the braking systems of many of 
its vehicles and minor redesigns of the rest. 
With the 20 percent gradient requirement, 
Chrysler will not have to complete any major 
redesigns. The agency estimates that 
Chrysler will have to complete minor 
redesigns on approximately 48 percent of its 
vehicles. 



A Supplement to the Final Regulatory 
Evaluation has been prepared to reflect these 
new conclusions and has been placed fn the 
docket. The figures contained in that 
document assume that the conforming 
amendment for school buses, discussed 
• above, will be made. If it is not made, 
substantially higher costs for school buses 
could be involved. Because of the larger 
number of vehicles that are now estimated to 
be affected, the new projected cost for 
parking brake requirements for Chryser is 
higher than previously estimated, despite the 
relaxation of the gradient requirement. The 
Supplement to the Final Regulatory 
Evaluation estimates that the parking brake 
requirements will result in a total cost to 
Chrysler of $1,271,400. The previous estimate 
was $442,000. The agency now estimates that 
the total costs of the parking brake 
requirements for Chrysler would have been 
in excess of $3,000,000 if the gradient 
requirement was left at 30 percent. 

While the agency now estimates that the 
20 percent grade will result in greater costs 
for Chrysler (though not for manufacturers 
as a whole) than originally estimated, the 
agency believes that those costs are justified. 
The parking brake of a vehicle performs an 
important safety function. It is vital that a 
vehicle's parking brake be able to hold the 
vehicle on the types of grades on which it is 
parked. Twenty percent grades are not 
uncommon in urban and residential areas, 
both on streets and driveways, where these 
vehicles are likely to be parked. In light of the 
relatively modest cost required to meet the 
20 percent grade requirement, the agency 
has determined that vehicles not meeting 
that requirement pose an unreasonable safety 
risk. As noted above, Standard No. 105 has 
required even large school buses, i.e., those 
with a GVWR greater than 10,000 pounds, to 
be tested on a 20 percent grade for several 
years. Also, Standard No. 121, Air Brake 
Systems, uses a 20 percent grade for large 
air-braked trucks. 

The change in gradient will result in cost 
savings to other manufacturers. The agency's 
new cost estimates for those manufacturers 
are set forth in the Supplement to the Final 



PART 571; S 105-83-PRE 72 



Regulatory Evaluation. Th^ agency estimates 
that while the number of vehicles requiring 
upgrading as a result of the parking brake 
requirements will not change for those 
manufacturers, less significant desigil 
changes will be needed to meet the new 
gradient requirement. The costs for those 
manufacturers will therefore be less than 
previously estimated. 

Service Brake Requirements: Technical Issues 

Chrysler's petition discussed several 
issues in addition to the parking brake 
requirements and requested withdrawal of 
the entire amendment pending further studies. 
That company stated, as it did in its comment 
on the notice of proposed rulemaking, that 
the test requirements are overly stringent 
and unreasonable because the test 
procedures are abusive to the brake system. 
According to that commenter, the test 
procedure is unrepresentative of real-world 
driving conditions and goes beyond the need 
for motor vehicle safety. Moreover, that 
commenter suggested that the requirements 
might cause manufacturers to bias the design 
of brake systems toward complying with the 
standard rather than providing brake 
systems that are balanced under all vehicle 
loading and driving conditions. 

The agency carefully considered and 
addressed those concerns in the preamble to 
the January 1981 final rule. Chrysler's 
petition neither addressed the statements 
made by the agency in response to those 
concerns nor indicated any consideration of 
changes made in the standard's requirements 
to assure that manufacturers have adequate 
leeway to produce well-balanced brake 
systems. The petition also did not cite any 
new issues or data related to those concerns. 
Moreover, as explained in the preamble to 
the final rule, the vast majority of light 
trucks sold today already meet all of the 
standard's performance requirements 
without experiencing any problems relating 
to the balancing of brake performance. 

Standard No. 105's test procedures were 
developed by the agency to assure that a 
vehicle's braking system meets minimum 



performance requirements under the varying 
types of conditions experienced in actual 
service. A vehicle's braking system is tested, 
for example, in new and broken-in conditions, 
at various speeds, while the vehicle is fully 
and lightly loaded, under varying conditions 
of fade, and under partial failure and failed 
power. 

Contrary to the assertions made by 
Chrysler's petition and as explained in the 
preamble to the final rule, the tests do 
represent the types of conditions 
experienced in actual service. For example, 
the standard's second fade test, which 
Chrysler has alleged in the past to be 
abusive, simulates the type of fade 
experienced during long mountain descents. 
The agency has verified that the 
temperatures produced by the test sequence 
are the same temperatures as sometimes 
experienced during long mountain descents. 

Chrysler's comment on the proposed rule 
requested only one change in the standard's 
requirements based upon the above-stated 
concerns, an -increase of 16 percent in fourth 
effectiveness (fully loaded) stopping 
distances. Chrysler stated that change was 
necessary to provide consumers with better 
balanced brake systems and to avoid the use 
of unproven load or deceleration sensing 
proportioning devices. As the preamble to 
the final rule explained, the proposed 
stopping distances were based on vehicle 
tests conducted by the agency using 
production vehicles with unaltered brakes 
and on confidential information provided by 
General Motors, Ford and Chrysler. These 
data indicated that recent models of almost 
all vehicles under 8,000 pounds GVWR 
passed the proposed requirements. 
Moreover, the agency determined that all 
vehicles subject to the standard could meet 
the proposed requirements without using 
unproven load or deceleration sensing 
proportioning devices by instead making 
modifications to such vehicle components a& 
brake linings, wheel cylinders, master 
cylinders, and combination valves. 

A vehicle's braking system which met the 
proposed requirements for Standard No. 105 
would be adequately balanced in that it would 



PART 571; S 105-83-PRE 73 



meet performance requirements under the 
varying conditions described above, most 
significantly when the vehicle was both 
loaded and unloaded. Based upon a number of 
comments received from manufacturers, 
however, as well as on a further evaluation of 
available data, the agency determined for the 
January 1981 final rule that the stopping 
distances for the fourth effectiveness test for 
vehicles with a GVWR of 8,000 to 10,000 
pounds should be extended by 10 percent. 
This change gave manufacturers additional 
leeway in balancing their braking systems, 
thus making it easier to design systems that 
are balanced for both fully loaded and lightly 
loaded conditions. 

The preamble to the final rule explained 
that since the agency had concluded that the 
requirements could be met as proposed for all 
vehicles (for both loaded and unloaded tests) 
without anti-lock or similar devices, the 
agency declined to adopt Chrysler's 
suggestion of a 16 percent extension of fourth 
effectiveness stopping distances. Instead, 
NHTSA chose the 10 percent extension 
suggested by a number of other manufacturers. 
The agency further determined, based on 
test data, that a 10 percent extension would 
be sufficient to make it easier for 
manufacturers to assure that their vehicle's 
braking systems perform well in both loaded 
and unloaded conditions. 

Neither Chrysler's comment on the notice 
of proposed rulemaking or its petition for 
reconsideration explained the derivation of 
its 16 percent figure. Moreover, Chrysler's 
petition for reconsideration did not indicate 
why the 10 percent extension was insufficient 
to meet the problem identified by Chrysler 
and did not either renew that company's 
request for a 16 percent extension, or raise 
any other issues concerning the matter. 

Safety Need, Costs and Benefits 

All three petitions for reconsideration 
challenged the extension of the standard on 
the bases of safety need and/or costs and 
benefits. Chrysler stated that the January 
1981 final rule would require it and probably 
other manufacturers to redesign service and 



parking brake systems of light duty trucks, 
buses and MPV's. According to that 
commenter, such changes would waste scarce 
resources in the absence of any demonstrated 
safety need. As explained above, the agency 
changed the parking brake requirements in 
response to Chrysler's concerns. Ford's 
petition requested withdrawal of the entire 
final rule because it believes there has been a 
complete lack of any valid demonstration by 
NHTSA that the implementation of the 
requirements may reasonably be expected to 
produce the safety benefits that have been 
projected for it and because it believes that 
the expenditures required to demonstrate 
conformity with the standard are excessive 
and inflationary. Ford's petition also stated 
that NHTSA has failed, based on data 
presented, to establish a safety need for the 
extension of the standard. The Brake System 
Parts Manufacturers Council stated in its 
petition that it did not believe that careful 
analysis has been conducted relating to the 
costs and benefits of the standard and that it 
does not believe that regulations should be 
adopted unless the benefits exceed the costs 
of the regulation. 

The issues of safety need and costs and 
benefits were discussed at considerable 
length in the preambles of the notice of 
proposed rulemaking and the final rule and in 
the Regulatory Evaluation which was 
prepared by the agency and made available 
to the public. As those documents indicate, 
the agency did carefully consider those 
issues. 

The safety need for the extension of the 
standard arises from the vital safety role 
played by a vehicle's braking system and the 
fact that many vehicles are produced with 
braking systems which can be significantly 
improved at an economical cost. In evaluating 
safety need, the agency carefully considered 
studies indicating the number and 
seriousness of accidents involving these 
vehicles, the overinvolvement of LTM's in 
fatal accidents as compared with passenger 
cars, the reduction in accidents that would 
result from improved braking systems, and 
the costs and feasibility of making such 
improvements. 



PART 571; S 105-83-PRE 74 



One of the agency's primary concerns 
about LTM braking is the differential in 
stopping distances between passenger cars 
and LTM's. Since light trucks, buses and 
MPV's share the same roads and traffic flow 
with passenger cars, they should ideally stop 
in the same distances. The preamble to the 
final rule explained, however, that there are 
differences between passenger cars and 
LTM's which make accomplishing that goal 
more difficult for LTM's. Therefore, taking 
those differences into account, the agency 
established stopping distances for light 
trucks, buses and MPV's which are slightly 
longer than those in effect for passenger cars. 
In light of the greater aggressiveness 
associated with LTM's as a result of their 
size, weight, and design, the agency 
determined that there is a safety need for 
LTM braking to be as optimal as is 
economically feasible, thereby reducing the 
differential in stopping distances between 
passenger cars and LTM's and reducing 
accidents involving those vehicles. 

Based on those considerations, the agency 
believes there is a safety heed to assure that 
the braking performance of all vehicles 
subject to the standard is at the optimal level 
which can economically be achieved. 
Approximately 25 percent of the vehicles 
subject to the amendment will require 
improved braking systems. Moreover, the 
rulemaking action has had and will continue 
to have an effect on the other 75 percent of 
vehicles. As is explained belpw, manufacturers 
have already improved the braking systems 
of many of their vehicles, largely as a result 
of this rulemaking. 

The agency believes there is a safely need 
to assure that those vehicles' braking 
performance is not downgraded. Increases in 
stopping distance are not without precedent. 
Stopping distances for passenger cars 
actually lengthened during the 1960's as a 
result of increased weight. Today, the agency 
is concerned that manufacturers might be 
tempted, in the absence of a standard, to 
reduce the braking performance of their 
vehicles as part of an effort to reduce weight 
and thereby improve fuel economy. Since 
some braking system components are 



relatively heavy, the braking system js a 
prime target for weight-reduction. The 
agency believes braking ability to be such an 
important safety factor that it should not be 
compromised by efforts to improve fuel 
economy. 

Contrary to assumptions made by Ford's 
petition for reconsideration, the agency did 
not issue the amendment to Standard No. 105 
solely because of the overinvolvement of 
LTM's in fatal accidents, as compared to 
passenger cars, and the rise in the trend of 
those accidents. Ford attempted to 
demonstrate in its petition that the 
overinvolvement of LTM's in fatal accidents 
is the result of a greater number of young 
males driving those vehicles rather than a 
problem with LTM braking ability. Ford also 
argued that there is no evidence that 
improved braking ability for LTM's will 
reverse the rise in the trend of fatal accidents 
involving those vehicles. 

The agency included in its Regulatory 
Evaluation an analysis of accident data 
involving LTM's. The agency stated that the 
overinvolvement of LTM's in fatal accidents 
suggests a probability that LTM's are 
deficient in accident preventative systems 
and/or that their weight and aggressiveness 
make them dangerous to pedestrians, 
bicyclists, and occupants of lower weight 
cars. The Regulatory Evaluation noted that 
in either case improvement of the braking 
systems of LTM's for greater accident 
prevention would serve to help fulfill the 
need for safety. 

Ford may be correct that the demographic 
profile of LTM drivers is another factor 
accounting for the overinvolvement of LTM's 
in fatal accidents. That would not change the 
fact that improved braking ability will reduce 
accidents. Similarly, the fact that the rise in 
the trend of fatal accidents involving LTM's 
has occurred during a period when brakirfg 
performance has either improved or been 
held constant does not alter the fact that 
further improvements in braking 
performance will produce additional safety 
benefits. There is a safety need for vehicles' 
braking systems to perform as optimally as is 
economically feasible. The agency has not 



PART 571; S 105-83-PRE 75 



claimed that improved braking performance 
will by itself reverse the rise in the trend of 
fatal accidents involving LTM's. The agency 
has determined that improved braking 
performance as a result of the amendment 
will reduce accidents that would occur in the 
absence of the standard and thereby save 
lives. 

The amendment to Standard No. 105 was 
issued by the agency in light of the total 
number of accidents involving LTM's and not 
just the increase in those accidents. As noted 
above, the agency evaluated the number and 
seriousness of accidents involving LTM's, the 
overinvolvement of LTM's in fatal accidents 
as compared with passenger cars, the 
reduction in accidents that would result from 
improved braking systems, and the costs and 
feasibility of making such improvements. 
Before issuing the notice of proposed 
rulemaking, the agency estimated both the 
costs and the benefits of the requirements and 
concluded that the costs of the amendment 
were justified by the benefits. Based upon all 
of these factors, the agency concluded that 
improving braking systems is a reasonable 
way of reducing some of the LTM accident 
problem. 

The rulemaking process for this 
amendment has been going on for a period of 
over 10 years. During the early 1970's, a final 
rule was issued establishing braking 
requirements for these vehicles. However, 
that rule was indefinitely delayed in 1975 
based upon economic considerations. Since 
that time, manufacturers have voluntarily 
made a number of improvements in their 
braking systems, largely following the 
requirements and test procedures of the 
delayed final rule. 

Because of the voluntary changes made by 
manufacturers in many of their vehicles since 
the previous final rule was delayed, as well as 
changes made by the agency in the new 
standard, the costs of the amendment are 
estimated to be only a small fraction of those 
of the delayed 1975 final rule. Manufacturers 
had submitted costs for the 1975 final rule for 
light to medium duty trucks that ranged from 
$54 to $775 per unit (depending on model 
configuration) to attain compliance with the 



standard. The agency compared those figures 
with independently gathered detailed cost 
information and determined that those 
estimates were accurate. 

Those figures have no relevance to the 
January 1981 final rule. Today, as a result of 
the voluntary changes made by manufacturers 
in many of their vehicles and changes made in 
the standard's requirements by the agency, it 
is estimated that the average cost of the new 
final rule will be only $2.53 per domestic 
LTM, or about $13.74 for each vehicle that 
needs to be upgraded. The costs for meeting 
the requirements for medium and heavy 
trucks (over 10,000 lbs GVWR) are estimated 
to be about $54 per vehicle. The total costs of 
meeting the standard's requirements for all 
trucks, buses and MPV's are estimated to be 
under $18,000,000. 

The agency made its estimates of costs on a 
company-by-company basis. In order to assure 
that its estimates were correct, the agency 
enlisted an outside contractor to independently 
assess the costs that would be involved. As 
the preamble to the January 1981 final rule 
explained more fully, the report substantially 
verified the cost estimates of the agency. Both 
the contractor's report and the agency's 
Regulatory Evaluation, which were available 
to the public in the docket, indicated the 
models which would require upgrading and 
the nature of the changes needed. 

Comments received from Ford and 
Chrysler on the notice of proposed 
rulemaking suggested that a greater number 
of vehicles would be affected by the standard 
than estimated by the agency. However, 
those comments gave only generalized bases 
for that assertion. While those commenters 
cited some additional braking system 
components that might require changes, they 
did not specify which vehicles would require 
changes or indicate what the nature or costs 
of those changes would be. Neither 
Chrysler's petition for reconsideration or 
that of Ford provided such information. 

The agency contacted Chrysler to obtain 
clarification of that company's assertions 
about the costs of the standard. As explained 
above, Chrysler provided information 
concerning changes that would be required as 



PART 571; S 105-83-PRE 76 



a result of the parking brake requirements. 
That company also provided test data to 
substantiate that information. Largely on the 
basis of that information, the agency changed 
the parking brake requirements and amended 
its cost estimates concerning those 
requirements. Chrysler did not provide 
information concerning the costs of the other 
requirements of the standard. In the absence 
of information contradicting the detailed 
studies on costs made by both the agency and 
an outside contractor for those other 
requirements, the agency continues to 
believe that its cost estimates are correct. 

The agency also contacted Ford to obtain 
clarification of its assertions about costs. 
Ford's petition stated that the amendment 
would result in $10,000,000 of certification 
related costs for that company and cause it to 
raise the suggested retail prices of its LTM's 
by an average of $11 per vehicle. By contrast, 
the agency's estimate of certification costs 
for Ford is only $130,000. Ford did not discuss 
the $130,000 figure, which was included in the 
Regulatory Evaluation, in its comment on the 
notice of proposed rulemaking. 

In response to the agency's request for 
clarification. Ford indicated that of the $11 
increase in costs that it projects, $8 is related 
to increased quality control by parts 
suppliers and $3 represents amortization of a 
$10 million initial investment. Of the $10 
million, $7.5 million was said to be for the 
purchase of nine chassis dynamometers and 
the upgrading of nine other dynamometers to 
be used to check brake performance at their 
nine truck plants. The remaining $2.5 million 
was attributed to engineering costs 
associated with compliance certification and 
quality control. 

In setting the requirements for the 
amendment, the agency specifically took into 
account production variability. All 
manufacturers balance their level of quality 
control with the margin of compliance that 
they believe is necessary to be confident of 
100 percent compliance. By designing braking 
systems for a level of performance which 
provides a sufficient margin of compliance to 
account ^or production variability, the 
substantial quality control costs cited by 



Ford should be made unnecessary. The 
agency took those factors into account when 
making its cost estimates and assumed that 
manufacturers would upgrade their vehicles' 
braking systems, where necessary, to 
provide a margin of compliance so as to make 
substantial quality control costs unnecessary. 
Further, the test requirements of Standard 
No. 105 do not specify the use of chassis 
dynamometers. While such devices may be 
useful for the purposes of quality control in 
, checking such vehicle components as braking 
systems, speedometers, and emissions 
systems, their use is neither necessary nor 
sufficient to assure compliance with Standard 
No. 105. 

On the issue of benefits, the Brake System 
Parts Manufacturers Council (BSPMC) cited 
in its petition a statement made in The 
Automobile Calendar by the United States 
Regulatory Council that NHTSA cannot 
predict the precise level of safety 
improvement resulting from the January 1981 
final rule because of the isolated effect of a 
number of interrelated accident factors, such 
as driver performance, vehicle responsiveness, 
and the variable characteristics of the 
highway and environment. That statement 
was cited by BSPMC as evidence that the 
agency does not know the benefits that the 
final rule will entail. 

Both the notice of proposed rulemaking 
and the preamble to the final rule explained 
that in carrying out the mandate of the 
National Traffic and Motor Vehicle Safety 
Act to issue vehicle safety standards to 
protect the public against unreasonable risk 
of vehicle accidents and of death and injury 
occurring as a result of such accidents, the 
agency is confronted with inherent problems 
that limit the degree of precision achievable 
in estimating the benefits of proposed 
standards. Engineering and accident 
analyses can clearly demonstrate that certain 
vehicle improvements will facilitate the 
performance of the driver's task and thereby 
improve safety. In this case, there is also a 
study showing that reducing stopping 
distances will reduce accidents. However, it 
is virtually impossible to isolate individual 
factors to arrive at precise and certain 



PART 571; S 105-83-PRE 77 



conclusions about the quantified benefits that 
will accrue. 

The notices explained that given the duty 
to act under this precautionary statute in the 
area of accident avoidance notwithstanding 
an inherent measure of imprecision and 
uncertainty, the agency has developed and 
issued accident avoidance standards while 
attempting within its capabilities to quantify 
the benefits of the standards and limit the 
uncertainty. Before issuing the proposal to 
amend Standard No. 105, the agency 
carefully evaluated and estimated the 
benefits that will accrue from the 
amendment. Those estimates were included 
in the Regulatory Evaluation prepared by the 
agency and made available to the public. 

Ford's petition challenged the statement in 
the Regulatory Evaluation that an average 4 
percent reduction in stopping distance 
capability will produce a 5 to 9 percent 
reduction in accidents where brakes are used. 
That statement, which was based on a study 
by the Institute for Research in Public Safety 
(IRPS), was used by the agency in projecting 
a reduction of 1,700 to 3,500 LTM-related 
accidents in the first year after the 
requirements became effective. The 
preamble to the final rule discussed the IRPS 
study at some length in response to a 
comment by Ford. 

Ford's petition did not discuss the agency's 
response to its comment regarding the IRPS 
study. Instead, Ford stated that it is 
"obvious" that a minor improvement (such as 

4 percent) in the maximum stopping distance 
capability of a vehicle can be utilized only in a 
very small proportion of accidents (well under 

5 percent). That commenter concluded that 
reductions in LTM accidents would be 
limited to only the 5 percent of accidents in 
which this maximum capability was utilized. 
According to Ford, that would make the 
projected benefits virtually disappear. 

Ford's petition gave no basis for its 
assertion that it is "obvious" that a 4 percent 
improvement in the maximum stopping 
distance capability of a vehicle can be utilized 
only in a very small proportion of accidents. 
Nor did Ford cite any source for its 5 percent 
figure. As noted above, the agency factored 



into its estimates of benefits the fact that 
brakes are used in about 50 percent of 
accidents. The 50 percent figure is derived 
from the IRPS study. 

Moreover, in addition to the projected 
reduction of 1,700 to 3,500 LTM-related 
accidents in the first year after the 
requirements become effective, the 
improvement in stopping distance capability 
will provide benefits in accident situations 
where brakes are used but the accident is not 
prevented. Those benefits will result from 
the fact that the vehicles will be traveling at 
a slower rate of speed when the accident 
occurs, thereby reducing the severity of the 
accident. For example, assuming a vehicle's 
maximum stopping distance capability is 
utilized from a speed of 60 mph, at the point 
where the improved vehicle is going less than 
2 mph, the unimproved vehicle would have 
been going about 13 mph. At the point where 
the iinproved vehicle is going 10 mph, the 
unimproved vehicle would have been going 
about 16 mph. In the absence of information 
contradicting the agency's estimates of 
benefits or the studies on which they are 
based, the agency continues to believe that its 
estimates of benefits are correct. 

NHTSA has considered the economic and 
other impacts of the January 1981 final rule 
and this amendment and has determined that 
they are not major within the meaning of 
Executive Order No. 12291. The agency has 
further determined that they are not 
significant within the meaning of the 
Department of Transportation regulatory 
procedures. Copies of the agency's 
Supplement to the Final Regulatory 
Evaluation may be obtained by writing 
NHTSA's Docket Section at the address 
given at the beginning of this notice. 

Although NHTSA has considered the 
effects of these amendments on small 
businesses, the agency has not prepared a 
regulatory flexibility analysis. Such an 
analysis is not necessary in this case, since 
the Regulatory Flexibility Act applies only to 
rules for which an NPRM was issued on or 
after January 1, 1981. The NPRM for the 
extension of Standard No. 105 to trucks. 



PART 571; S 105-83-PRE 78 



buses and MPV's was published in October Issued on December 15, 1981. 

1979. 

The agency has also analyzed these 

amendments for purposes of the National' Raymond A. Peck, Jr. 

Environmental Policy Act and has Administrator 

determined that they will not have a 46 F.R. 61887 

significant effect on the human environment. December 21, 1981 



PART 571; S 105-83-PRE 79-80 



PREAMBLE TO AN AMENDMENT TO 
FEDERAL MOTOR VEHICLE SAFETY STANDARD NO. 105 

Hydraulic Brake Systems 
[Docket No. 70-27; Notice 28] 



ACTION: Final rule. 

SUMMARY: This notice amends Standard No. 105, 
Hydraulic Brake Systems, to provide an optional 
test procediu-e for trucks, buses other than school 
buses, and multipurpose passenger vehicles 
(MPV's) with a gross vehicle weight rating (GVWR) 
of greater than 10,000 pounds. The standard 
becomes applicable to these vehicles on September 
1, 1983. The amendment permits manufactiu"ers 
to meet the partial failure requirements after con- 
ducting the standard's full test sequence preceding 
the partial failure test instead of the abbreviated 
test sequence generally specified for these vehicles. 
Under this option, manufacturers continue to be 
required to meet only the requirements of those 
tests in the abbreviated test sequence. 

EFFECTIVE DATE: September 1, 1983. 

SUPPLEMENTARY INFORMATION: Standard No. 
105, Hydraulic Brake Systems, provides that 
vehicles must meet a variety of performance re- 
quirements when tested according to a lengthy list 
of test procedures and in the sequence in which the 
procedures are listed by the standard. Currently, 
the standard is only applicable to passenger cars 
and school buses. However, effective September 1, 
1983, the standard becomes applicable, in whole 
or in part, to trucks, all tjT)es of buses, and 
multipurpose passenger vehicles. (Final rule 
published in the Federal Register (46 FR 55) on 
January 2, 1981; response to petitions for recon- 
sideration published December 21, 1981 (46 FR 
61887).) 

While Standard No. 105 was extended on a 
general basis (with some modifications) to vehicles 



with a gross vehicle weight rating (GVWR) of 
10,000 pounds or less, only limited requirements 
were made applicable to vehicles with a GVWR 
greater than 10,000 pounds. (The standard's full 
requirements already applied to all school buses, 
including those with a GVWR greater than 10,000 
pounds.) The abbreviated test sequence applicable 
to heavy vehicles other than school buses is similar 
to the full test sequence, except that many of the 
tests are eliminated. 

On July 14, 1983, in response to concerns raised 
by General Motors (GM) about an appEU'ent 
anomaly in the test procedure, NHTSA published 
a notice of proposed rulemaking (NPRM) in the 
Federal Register (48 FR 32202) to provide an op- 
tional test procedure for heavy vehicles other than 
school buses. As explained in that notice, the 
agency was informed by GM that some of its heavy 
vehicles were having difficulties in meeting Stan- 
dard No. 105's partial failure requirements under 
the limited test sequence. (The partial failure test 
ensures that a vehicle's brakes £ire capable of 
bringing the vehicle to a controlled stop in a 
reasonable distance if a part of the service brake 
system should fail.) Under the full test sequence, 
the partial failure test is conducted well into the 
test sequence, following three effectiveness tests, 
burnish and rebiu"nish (i.e., break-in or condition- 
ing) procedvu-es, and the parking brake test. Of 
these various steps, only one, the burnish pro- 
cedure, is included in the limited test sequence. 

GM informed NHTSA that it discovered, late in 
its compliance testing, that certain of its heavy 
vehicles, as designed, were unable to meet the par- 
tial failure requirements under the limited test se- 
quence. However, the same vehicles would meet 
the partial failure requirements if tested imder the 



PART 571; S 105-83-PRE 81 



full test sequence. 

According to GM, redesign of some of its heavy 
vehicle braking systems wovild be required to meet 
the partial failiu-e requirements under the limited 
test sequence. That company stated that in the 
short run the minimiun cost resulting from such 
redesign would be in excess of $100 per vehicle, 
without improving user safety. Annual production 
of approximately 20,000 vehicles would be afiFected. 
Given the economic consequences of this apparent 
anomaly related to the test procedure, GM re- 
quested that the standard be amended to correct it. 

Afler analyzing the issues raised by GM, NHTSA 
agreed that the standard should be amended. The 
NPRM explained that the elimination of the other 
procedures from the limited test sequence could 
have the effect of increasing the stringency of the 
later ptirtial failiu-e test. The reason for this is that 
some brakes tend to become more effective as they 
are tested, because temperature conditioning im- 
proves the friction of the brake pads. 

The NPRM also explained that the increased 
stringency of the partial failiu"e test under the 
limited test sequence was neither intended nor 
foreseen by the agency. Indeed, the stopping 
distances for the partial failure test were based on 
the assumption that the full test sequence would 
be conducted. The same stopping distances are ap- 
plicable to heavy school buses, but they are tested 
under the full test sequence. 

NHTSA proposed that manufactiu-ers be given 
the option of subjecting their heavy vehicles to the 
full test sequence preceding the partial failure test 
instead of the limited test sequence. The NPRM ex- 
plained that manufacturers would not be required 
to meet performance requirements associated with 
the additional tests under this proposed option. 
However, manufacturers would be required to con- 
duct the additional tests in accordance with the 
standard's specified test procediu"es. 

Three comments were received by the agency, all 
of which supported adoption of the proposed amend- 
ment. GM commented that the NPRM properly 
described the situation as an unexpected and unin- 
tended increase in test stringency arising solely 
from the elimination of several test sequence steps 
in the interest of test efficiency and that the dif- 
ficulty is only one of procedure and not one that 
in any way affects motor vehicle safety. That com- 
pany emphasized that the brake system in ques- 
tion is very similar to that on its school buses of 
equivalent GVWR and when tested to the full se- 



quence schedule, as is the school bus system, meets 
all applicable requirements. 

GM also stated that the proposed solution is the 
most logical approach to elimination of this unin- 
tended increase in stringency. That company noted 
that giving the manufacturer the option to choose 
whether its vehicles are tested to the full or ab- 
breviated test sequence enables systems which 
have been developed to meet the full school bus re- 
quirements to also comply when used on trucks, 
without additional complication, while also allow- 
ing a manufacturer which has developed a system 
to comply with the abbreviated test sequence to use 
that system without additional testing. 

Ford commented that it agrees with the agency's 
analysis that the elimination of certain procediu-es 
from the test sequence applicable to vehicles other 
than the subject heavy vehicles could have the ef- 
fect of increasing the stringency of the partial 
failure test in the abbreviated test sequence, and 
that it supports the proposed amendment. Chrysler 
submitted a comment which stated that it concurs 
with the proposed amendment. 

After reviewing the comments, NHTSA has 
determined that the eimendment should be adopted 
as proposed. An effective date of September 1, 1983, 
is provided. The agency has determined that an ef- 
fective date of such short notice is in the public in- 
terest given the imminence of the September 1, 
1983, effective date for Standard No. 105's applic- 
ability to these vehicles, and the optional nature 
of the amendment. 

The agency has considered the costs and other 
impacts of this amendment and has determined 
that it is not major within the meaning of Ex- 
ecutive Order 12291 or significant within the 
meaning of Department of Transportation's 
regulatory procedures. Further, the agency con- 
cludes that the economic and other consequences 
of the amendment are so minimal as not to require 
preparation of a full regulatory evaluation. Due to 
the optional nature of the amendment, no new costs 
are imposed on manufacturers or consumers. The 
amendment will result in some cost savings to 
manufacturers and consumers since it eliminates 
the need for redesign of some brake systems. In the 
short run, these savings could be relatively high 
on a per vehicle basis. As noted above, GM 
indicated that short-run redesign costs would have 
been in excess of $100 per vehicle, had the standard 
remained unchanged. In the longer run, however, 
NHTSA believes that these savings would probably 



PART 571; S 105-83-PRE 82 



be low, since, with a long leadtime, manufacturers 
could likely redesign their brakes at a much lower 
cost to comply with the requirements under the 
abbreviated test sequence. 

The agency has considered the effects of this pro- 
posal in relation to the Regulatory Flexibility Act. 
I certify that this amendment will not have a 
significant economic impact on a substantial 
number of small entities. Small businesses will be 
affected by the amendment only to the extent that 
they are sellers or purchasers of affected vehicles. 
Small organizations and small government 
jurisdictions will only be affected to the extent that 
they are purchasers of affected vehicles. The 
amendment will result in some lower vehicle 
prices, thereby benefitting both sellers and pur- 
chasers. However, such savings are sufficiently 
small relative to the purchase price of heavy 
vehicles, even in the short run when they are ex- 
pected to be at their highest, that they are unlikely 
to significantly affect purchasing decisions. 

Finally, the agency has analyzed this amend- 
ment for §571.105 [Amended]. 



Section S7 is amended by revising the paren- 
thetical after the first sentence of the paragraph 
to read as follows: 

(For vehicles only having to meet the re- 
quirements of S5.1.2 and S5.1.3 in section S5.1, the 
applicable test procedures and sequence are S7.1, 

57.2, S7.4, S7.9, S7.10 and 87.18. However, at the 
option of the manufacturer, the following test pro- 
cedures and sequence may be conducted: S7.1, S7.2, 

57.3, S7.4, S7.5, S7.6, S7.7, S7.8, S7.9, S7.10 and 
S7.18. The choice of this option shall not be con- 
strued as adding to the requirements specified in 
S5.1.2 and S5.1.3.) 

Issued on August 30, 1983 



Diane K. Steed, 
Deputy Administrator 

48 F.R. 39939 
September 2, 1983 



PART 571; S 105-83-PRE 83-84 



PREAMBLE TO AN AMENDMENT TO MOTOR VEHICLE SAFETY STANDARD NO. 105 

Hydraulic Brake Systems; Controls and Displays 
[Dockets No. 1-18, Notice, 32; No. 70-27, Notice 31] 



ACTION: Final rule. 

SUMMARY: Federal Motor Vehicle Safety Stand- 
ards No. 105, Hydraulic Brake Systems, and No. 
101, Controls and Displays, have required telltales 
whose single function is indicating failure in the 
antilock portion of a brake system to read 
"ANTILOCK." This notice amends those stand- 
ards to permit "ABS," an abbreviation for "Anti- 
lock Brake System," as an alternative. 

DATES: The amendments made by this rule are 
effective June 29, 1987. 

SUPPLEMENTARY INFORMATION: Federal Motor 
Vehicle Safety Standard No. 105, Hydraulic Brake 
Systems, requires an indicator lamp, i.e., a telltale 
on the dashboard, to be activated whenever there 
is a total functional electrical failure in an antilock 
brake system. The manufacturer may meet this re- 
quirement by using a common indicator display- 
ing the word "BRAKE,", which also warns the 
driver about other types of brake failure. Alter- 
natively, the manufacturer may provide a separate 
indicator for antilock failure. 

If the manufacturer uses a separate indicator for 
antilock failure, Standard No. 105 and Standard 
No. 101, Controls and Displays, have specified that 
the indicator must read either "ANTILOCK" or 
"ANTI-LOCK." On April 16, 1986, NHTSA 
published a notice of proposed rulemaking (NPRM) 
in the Federal Register (51 FR 12900) to permit 
"ABS," an abbreviation for "Antilock Brake 
System," as an alternative. 

As discussed in the NPRM, this rulemaking ac- 
tion resulted from a petition for rulemaking sub- 
mitted by Mercedes-Benz. That company stated 
that the letters "ABS" have been used in 
automotive press articles and in manufacturers' 
print advertising, with few ej^eptions; for identi- 
fying brake systems with antilock capabilities. 
Copies of such publications were submitted with 
the petition. The petitioner contended that as anti- 
lock brake systems increase in availability, the ab- 
breviation will be increasingly used by the media, 
in technical publications, and in owners' manuals. 



and is expected to remain synonymous with this 
type of brake system. 

Mercedes also argued that if a manufacturer of- 
fers a system or feature not required by regulation, 
but provides a con-esponding telltale required by 
regulation, that telltale message should be per- 
mitted to correspond with the campaigns developed 
to promote such safety systems. That company 
compared the use of "ABS" in its marketing of 
antilock braking systems to the use of "SRS" in 
marketing its Supplementary Restraint System. 

In the NPRM, NHTSA stated that it believed 
that the primary issue it must consider in respond- 
ing to Mercedes' petition is the recognizability and 
understanding of "ABS" as compared to 
"ANTILOCK," both by new car buyers and other 
drivers. For example, in deciding not to adopt the 
International Standards Organization (ISO) brake 
symbol as an alternative to the word "BRAKE" in 
common indicators, the agency noted a Society of 
Automotive Engineers (SAE) study indicating ex- 
tremely low percentage recognition for the ISO 
brake symbol compared to the word "BRAKE," 
and the importance for safety of drivers under- 
standing the meaning of the brake indicator lamp. 
See 50 FR 23430 (June 4, 1985). 

NHTSA indicated in the NPRM that it was 
unaware of data concerning the recognizability and 
understanding of "ANTILOCK" or "ABS." The 
agency recognized that, unlike some identifying 
words and abbreviations, the abbreviation ABS ap- 
pears to require learning by the driver in order to 
understand its meaning. However, given the use 
of ABS by the media and in marketing campaigns, 
the agency agreed with the petitioner that such 
learning is likely to be taking place and to continue 
to do so. The agency also noted that the word 
"ANTILOCK" requires learning by the driver in 
order to understand its meaning, since antilock 
technology is relatively new and unfamiliar to 
most drivers. NHTSA specifically requested com- 
ments and data on the recognizability and 
understanding of "ANTILOCK" and "ABS." 

NHTSA received nine comments on the NPRM, 



PART 571; S105-PRE 85 



some of which favored the proposal and some of 
which opposed it. Commenters supporting the pro- 
posal include Chrysler, Ford, Volkswagen, BMW, 
American Motors (AMC) and Volvo. Chrysler 
stated that with the expected increase in usage of 
antilock brake systems and accompanying owner 
information and advertising campaigns, both 
"ANTILOCK" and "ABS" should be recognizable 
and understandable to drivers of those cars. Ford 
stated that it supports the proposal since (1) it 
represents more efficient use of space in labeling 
a small telltale, (2) that company has used the term 
"ABS" to designate its antilock brake systems, (3) 
the "ABS" designation has been recognized by the 
International Standards Organization (ISO) as part 
of one of its proposals for an antilock brake sym- 
bol, and (4) that company probably would employ 
the "ABS" identification in its products worldwide 
if it is permitted by NHTSA for use in the United 
States. That company cited data suggesting that 
"ABS" currently has lower recognition than 
"ANTILOCK," but pointed out that an abstract 
symbol, such as "ABS," can be learned just like 
a word in another language or a new slang word. 
BMW asserted that since both antilock braking 
systems and separate telltales for them are volun- 
tarily provided, manufacturers should be provided 
maximum flexibility in telltale identification. That 
company stated that both messages are equally 
unknown to the driving public and that neither is 
self-explanatory. BMW also noted that, unlike the 
other required brake telltales, complete loss of this 
function does not interfere with normal braking. 
That commenter stated that this is reflected by 
Standard No. lOl's traditional designation of the 
color yellow for this telltale, in contrast to red for 
the others, indicating less urgency. AMC 
acknowledged that the introduction of "ABS" 
would necessitate some education of drivers, but 
asserted that it is opportune that this be done now, 
as the new antilock technology is gradually being 
integrated into vehicle designs. Volkswagen noted 
that while the provision of multiple brake indicator 
lights can add significantly to the amount of infor- 
mation provided to the driver, the amount of in- 
formation which can be printed on a telltale is 
usually quite limited. That company supported use 
of "ABS," arguing that inflexibility with regard 
to the abbreviated message to be displayed is not 
reasonable. 

Commenters opposing the proposal include 
Honda, Renault, and a private individual, Mr. 
Robert F. Schlegel, Jr. Honda stated that other ab- 
breviations for Antilock Brake System are in use 
by other manufacturers, including "ALB" (Anti- 
Lock Brake), "ASBS" (Anti-skid Brake System), 



"ESC" (Electronic Skid Control), and "SCS" (Stop 
Control System). That commenter stated that these 
various abbreviations, including "ABS," are 
trademarks, and expressed concern that the wide 
use of "ABS" with the Bosch antilock brake system 
may lead consumers to believe that any vehicle 
with a telltale showing the letters "ABS" is equip- 
ped with a Bosch system. Based on this concern, 
Honda argued that it is neither wise nor lawful for 
NHTSA to permit such use. Renault similarly com- 
mented that the abbreviation "ABS" is commonly 
associated with a particular anti-skid device, or 
with a particular manufacturer. That company 
stated that there is no reason to assign a greater 
value to this abbreviation than to other ones which 
may appear. Renault stated that the French 
manufacturers have proposed a pictorial symbol for 
antilock failure to the ISO, which is also currently 
considering two other symbols. Since the ISO has 
not yet ruled on an international symbol for anti- 
lock failure, that commenter requested that Stand- 
ards No. 101 and No. 105 not be amended at this 
time. Renault also argued that if "ABS" is permit- 
ted, other symbols, particularly those before the 
ISO, should also be permitted. Mr. Schlegel argued 
that the word "ANTILOCK" conveys more infor- 
mation than "ABS" to the vast majority of drivers, 
contending that symbols must provide a pictorial 
or verbal clue. According to that commenter, there 
are too many acronyms arriving lately that are not 
understood by the general public. 

After careful consideration of the comments, 
NHTSA has decided to permit the use of "ABS" 
as an alternative to "ANTILOCK." The use of 
multiple brake indicators can provide additional 
safety information to the driver, and the agency 
believes that greater flexibility is appropriate. The 
message "ABS" is considerably shorter than 
"ANTILOCK" and is therefore more easily incor- 
porated into a small telltale. 

NHTSA recognizes that "ABS" will require 
learning on the part of drivers. For example, in an 
informal survey of 40 Ford engineering employees, 
15 percent associated "ABS" with antilock brakes, 
while 72 percent recognized the word 
"ANTILOCK." As indicated in information pro- 
vided by Mercedes-Benz and BMW, however, the 
term "ABS" is being used in both press articles and 
advertising. NHTSA believes that drivers are learn 
ing the meaning of "ABS," and that such learn- 
ing will continue. NHTSA notes that there are dif- 
ferences between this situation and that involved 
in the agency's decision not to permit use of the 
ISO brake symbol. First, the telltale for antilock 
failure is not as urgent or critical a warning as that 
for other types of brake failure. Second, there is ex- 



PART 571; S105-PRE 86 



tensive use of the term "ABS" in press articles and 
advertising, which is not the case for the ISO brake 
symbol. Third, as antilock technology is still in the 
early stages of being introduced to drivers, there 
is a unique opportunity for learning the term 
"ABS." By contrast, drivers have come to expect 
use of the word "BRAKE" for other types of brake 
failure. 

While NHTSA believes that greater flexibility 
is appropriate, it does not beheve it would be in the 
interest of safety to permit multiple acronyms or 
symbols. While permitting the use of "ABS" will 
facilitate the learning of that acronym by drivers, 
drivers cannot be expected to learn the meaning 
of multiple acronyms or symbols for the same 
message. NHTSA notes that this action may help 
facilitate international harmonization, since one 
of the symbols being considered by the ISO for 
antilock failure incorporates "ABS." 

Since NHTSA considers it appropriate to permit 
only one alternative to "ANTILOCK," it is 
necessary that use of that alternative be available 
to all manufacturers. Accordingly, the agency con- 
tacted Mercedes-Benz concerning whether its 
parent company, Daimler-Benz, was willing to 
waive protection of its trademark and grant a 
general approval to use "ABS" for all types of 
antilock braking systems. Daimler-Benz executed 
a declaration, which included the following 
statement: 
If the term "ABS" is permitted under 49 CFR 
Part 571, Federal Motor Vehicle Safety Stand- 
ards, by the National Highway Traffic Safety Ad- 
ministration, United States Department of 
Transportation, as an alternative to "ANTI- 
LOCK" for identifying telltales for malfunctions 
in antilock brake systems, Daimler-Benz 
Aktiengesellschaft hereby declares that it waives 
the protection of its trademark and grants a 
general approval to use the term "ABS" as a sym- 
bol for all types of anti-lock brake systems. 
The declaration executed by Daimler-Benz has 
been placed in the docket. NHTSA believes that 
the waiver resolves the trademark concerns raised 



by commenters. Since it is clear that all manufac- 
turers can now use "ABS," the agency does not 
believe consumers will associate the term with any 
particular company. 

Since this amendment imposes no new require- 
ments but instead increases manufacturer flexibil- 
ity by relieving a restriction, NHTSA has deter- 
mined that an effective date of 30 days after 
publication in the Federal Register is in the public 
interest. 
Part 571-lAMENDED] 

In consideration of the foregoing, 49 CFR Part 
571 is amended as follows: 

In Table 2 of 571.101, the identifying words or 
abbreviation for malfunction in anti-lock (row 9, 
column 3, above the dotted line) is revised to read: 

Antilock, Anti-lock, or ABS. Also see FMVSS 
105. 

S5. 3. 5(a) of 571.105 is revised to read: 

S5.3.5(a) Each indicator lamp shall display word, 
words or abbreviation, in accordance with the re- 
quirements of Standai-d No. 101 (49 CFR 571.101) 
and/or this section, which shall have letters not less 
than 1/8-inch high and be legible to the driver in 
daylight when lighted. Words in addition to those 
required by Standard No. 101 and/or this section 
and symbols may be provided for purposes of 
clarity. 

S5.3.5(cXlXC) of 571.105 is revised to read: 

(C) If a separate indicator lamp is provided for 
an anti-lock system, the single word "Antilock" or 
Anti-lock," or the abbreviation "ABS," may be 
used for S5.3.1(c). 

Issued on May 21, 1987 



Diane K. Steed 
Administrator 

52 F.R. 19872 
May 28, 1987 



PART 571; S105-PRE 87-88 



PREAMBLE TO AN AMENDMENT TO FEDERAL MOTOR VEHICLE SAFETY 

STANDARD NO. 105 

Burnish Procedures for Heavy Duty Vehicles 
[Docket Nos. 70-27; Notice 29 and 83-07; Notice 4] 



ACTION: Final rule. 

SUMMARY: Before a vehicle is tested for com- 
pliance with most of the requirements of this 
agency's braking standards, the vehicle's brakes 
are broken-in by a series of brake applications. 
This break-in is called a burnish, and is intended 
to simulate the break-in that a vehicle's brakes 
would get when they are initially used on the 
public roads. With respect to heavy vehicles (those 
with a gross vehicle weight rating greater than 
10,000 pounds), the burnish procedure now re- 
quires that the brakes be heated to not more than a 
specified maximum temperature by means of a 
series of brake applications. 

The agency initiated rulemaking regarding 
this temperature limit because the limit is more 
favorable to drum brake designs than to disc 
brake designs. This situation arises because the 
limit was based on drum brake systems whose 
normal safe operating temperatures are signifi- 
cantly lower than those of disc brake systems. As a 
result, disc brake systems may not be adequately 
broken-in under the current burnish procedure. 

To address this problem, this rule establishes a 
new burnish procedure for vehicles with a gross 
vehicle weight rating (G VNR) greater than 10,000 
pounds. Under this new procedure, the vehicle 
will make 500 brake applications to slow the 
vehicle from 40 to 20 miles per hour (mph), 
without regard to the resulting temperature. This 
procedure will break-in brakes in a manner that is 
more realistic and representative of the break-in 
the vehicle brakes actually get when in service on 
the roads, without favoring any particular braking 
system design. 

Since this new burnish procedure may affect 
the design and certification of new and existing 
braking systems, the agency believes it is approp- 
riate to allow a transition period for implement- 
ing this new burnish procedure. Therefore, this 
rule allows manufacturers to base the certifica- 
tion of their heavy vehicle brakes on either the 
new or the old burnish procedures until Sep- 
tember 1, 1993. In testing a vehicle for com- 
pliance, the agency will use the same procedures 
on which the manufacturer's certification of com- 



pliance was premised. All vehicles manufactured 
on or after September 1, 1993, will be burnished 
under the new burnish procedures set forth in this 
rule. 

DATE: This rule is effective September 12, 1988. 

SUPPLEMENTARY INFORMATION: 

Backgrou >id and Notice of Proposed Rulemaking 

NHTSA has established two standards appli- 
cable to the braking systems on vehicles with a 
gross vehicle weight rating greater than 10,000 
pounds. These two standards are Standard No. 
105. Hydraulic Brake Systems {AdCFR §571.105) 
and Standard No. 121, Air Brake Systems (49 
CFR §571.121). Standards No. 105 and 121 both 
specify road tests to measure the brake systems' 
compliance with the performance requirements. 
Both standards specify also that the brake systems 
on these heavy vehicles shall be "burnished" before 
undergoing road testing to determine if the brake 
systems satisfy the performance requirements of 
the applicable standard. The burnish is a series of 
brake applications that serve to "break-in" the 
brakes on a new vehicle. 

Before the initiation of this rulemaking, the 
burnish procedure was as follows. The burnish 
consisted of a series of 500 brake applications at 
specified speeds. During the burnish procedure, 
the maximum temperature of the hottest brake on 
the vehicle was not permitted to exceed 550° F. 
The first 175 brake applications (hereinafter 
referred to as "snubs") were made so as to slow the 
vehicle from 40 miles per hour (mph) to 20 mph. 
Subsequent snubs were conducted at initial speeds 
that increase in increments of 5 mph until the 
final series of snubs brake the vehicle from 60 
mph to 20 mph. However, if the maximum allow- 
able brake temperature were reached at some 
speed less than 60 mph, the speed was not increased 
for the following snubs. The snub speed could even 
be reduced if such a reduction were needed to 
maintain the brake temperature below the 
specified maximum level. 

Standard No. 121 also specifies a dynamometer 
test. The burnish for brake systems to be tested on 
the dynamometer specifies a series of 400 brake 



PART571;S105-PRE89 



applications from 40 mph, at a specified rate of 
deceleration. For these brake applications, Stand- 
ard No. 121 specifies that the initial brake 
temperature shall be within a stated range. The 
initial brake temperature is defined in section S4 
of Standard No. 121 as "the average temperature 
of the service brakes on the hottest axle of the 
vehicle 0.2 miles before any brake application." 

The maximum brake temperatures during the 
road test burnish, which apply to both disc and 
drum brake systems, were based on SAE Recom- 
mended Practice J880, "Brake System Rating 
Test Code — Commercial Vehicles." This recom- 
mended practice was established in 1963, based 
solely on test data for drum brakes. One problem 
that became apparent with respect to the maxi- 
mum burnish temperatures specified in the 
standards was that the specified maximum 
temperature may not have been appropriate for 
disc brake systems. Disc brake systems are 
generally designed to operate at appreciably 
higher temperatures than are drum brake systems. 
It has been difficult to avoid exceeding the specified 
550° F maximum temperature during the burnish 
of vehicles with disc brake systems, even at the 
lowest of the burnish speeds set forth in the 
standards, i.e., 40 mph. 

In response to this situation. International Har- 
vester (IH) filed a petition for rulemaking with 
NHTSA. In its petition, IH asked the agency to 
amend the burnish procedures to take account of 
the differing characteristics of disc and drum 
brake systems. International Harvester has sub- 
sequently changed its corporate name to Navistar. 
However, all of the material in the public docket 
for this rulemaking action identify the company 
as International Harvester. To avoid potential 
confusion, this preamble refers to the company as 
International Harvester. 

Notice of Proposed Rulemaking 

After granting this petition, the agency pub- 
lished a notice of proposed rulemaking (NPRM) at 
48 FR 29560; June 27. 1983. The NPRM proposed 
to amend the sections of Standards No. 105 and 
121 applicable to burnish before road testing as 
follows. If the temperature of the hottest brake 
exceeded 550° F at a snub condition of 40 to 20 
mph, the remaining snubs would be run from 40 to 
20 mph without regard to the brake temperature. 
NHTSA anticipated that this proposed change 
would not create any compliance problems for 
existing drum brake systems, which do not typi- 



cally exceed the specified temperature during 
burnish, while resolving the burnish problems 
that could occur for disc brake systems. 

No change was proposed for the dynamometer 
burnish temperature in Standard No. 121 because 
the temperature problems which had arisen during 
the road test burnish had not occurred with 
respect to the dynamometer burnish. Accordingly, 
NHTSA saw no reason to propose changing that 
burnish procedure. 

The NPRM also proposed some more minor 
revisions to the standards. One proposed change 
was intended to clarify the procedure for loading 
tractors and trailers during burnish testing. 
Another proposed change would have specified 
brake adjustments at equal intervals during the 
burnish. This change was proposed to ensure 
uniformity and repeatability of test results. The 
final proposed change involved automatic slack 
adjusters and automatic brake adjusters. Under 
the NPRM, both standards would have been 
amended to specify that brake systems equipped 
with such devices could not deactivate the devices 
during the testing for compliance with Standards 
No. 105 and 121. 

The agency received seven comments on the 
NPRM. Motion Control Industries (Motion Con- 
trol) suggested in its comments that NHTSA 
delete entirely the temperature restrictions dur- 
ing the burnish. In support of this position. Motion 
Control asserted that the existing burnish proce- 
dures do not sufficiently condition rear drum 
brakes on vehicles equipped with disc brakes on 
the front axle. This assertion was based on the fact 
that the temperature of the front disc brakes will 
exceed 550° F during the 40 to 20 mph snubs, and 
so the vehicle would not run any snubs at speeds in 
excess of 40 mph. The failure to condition the rear 
drum brakes at the higher snub speeds meant, 
according to Motion Control, that those drum 
brakes would not perform as well as they are 
designed to do during the compliance testing. 
Motion Control contended that if the friction 
materials in the brake systems are designed to 
stop vehicles from 60 mph while in service and are 
subjected to 60 mph stops during testing, it is 
desirable for the friction materials to experience 
whatever temperatures result from 60 mph stops 
during the burnish. 

In a related vein, Ford Motor Company (Ford) 
stated that the amendment set forth in the NPRM 
would relieve the problems encountered by vehicles 
with disc brakes on all axles, but would not 
achieve its purpose for vehicles equipped with a 



PART571;S105-PRE90 



combination of disc and drum brakes. According 
to Ford's comment, "the procedure which would 
burnish the brakes most effectively on a vehicle 
equipped with a combination of disc and drum 
brake systems would be one which maintained the 
drum brake temperatures within the window of 
450°-550° F, while allowing the disc brake 
temperatures to find their own level, unrestricted." 
This suggestion was similar to Motion Control's, 
in that no temperature restrictions would apply to 
disc brake systems. If the Ford suggestion were 
adopted, vehicles with disc brake systems on all 
axles would not be subject to any temperature 
limitations during the burnish procedure. How- 
ever, the Ford suggestion would have retained the 
temperature limitations for drum brake systems. 
After publication of the NPRM, NHTSA had 
conducted some testing to determine what bur- 
nish procedures would expose heavy duty vehicle 
brakes to sufficiently high temperatures to simu- 
late a break-in of the brakes under normal driving 
conditions without favoring any particular design. 
That testing indicated that heavy duty vehicle 
brakes should be burnished by 500 snubs slowing 
the vehicle from 40 to 20 mph, without regard to 
the brake temperatures generated during the 
burnish. Such a burnish procedure exposes all 
types of brake systems to the temperatures they 
are likely to experience in city driving, without 
penalizing or favoring any particular type of 
brake design. Such a procedure would also be 
consistent with the burnish procedures specified 
by the Society of Automotive Engineers (SAE) for 
heavy duty vehicle brake performance testing; see 
SAE Recommended Practice J786a. (The burnish 
procedure in SAE Recommended Practice J880a, 
allowing snubs from 60 to 20 mph, is for a brake 
energy absorption test, not a brake performance 
test). 

Supplementary Notice of Proposed Rulemaking 



The agency wanted to give the public an oppor- 
tunity to comment on the approaches suggested by 
Ford and Motion Control and the agency research, 
before proceeding to establish a final rule. Ac- 
cordingly, NHTSA published a supplementary 
notice of proposed rulemaking (SNPRM) at 50 FR 
21313; May 23, 1985. The SNPRM proposed four 
alternative methods for amending the burnish 
procedures. These were the Ford approach, the 
Motion Control approach, the approach suggested 
by the agency research, and the approach origi- 



nally proposed in the NPRM with some minor 
changes. 

Further, the SNPRM asked for additional com- 
ments on the minor amendments proposed in the 
NPRM. First, the NPRM had erroneously pro- 
posed the following conditions for burnishing the 
brakes of a truck tractor. As proposed, the truck 
tractor would be loaded to its gross vehicle weight 
rating and a trailer attached to the tractor would 
be loaded to its gross axle weight rating. However, 
the NPRM would have required that the control 
trailer be unbraked. Such loading would overtax 
the tractor's brakes during the burnish, since 
those brakes would be stopping far more weight 
than they were designed to stop. To correct this 
error, the SNPRM proposed to require that the 
combination of the tractor and the unbraked 
trailer be loaded only to the gross vehicle weight 
rating of the tractor. 

Second, the NPRM had proposed that brake 
adjustments be made at specified intervals during 
the burnish procedure. Past interpretations and 
preambles had repeatedly stated that brake 
adjustments were permitted during burnish. To 
establish uniformity for both manufacturer and 
agency testing as to when such adjustments would 
be made, the NPRM proposed that the brakes be 
manually adjusted at specified intervals. In the 
case of the road test burnishes, the adjustments 
would be made manually after 125, 250, and 375 
snubs, in accordance with the manufacturer's 
recommendations. For the dynamometer test 
burnishes specified in Standard No. 121, the 
brakes would be adjusted manually after 100, 200, 
and 300 snubs. 

General Motors (GM) objected to the proposed 
brake adjustment procedures in its comments on 
the NPRM. While acknowledging that manual 
adjustment might provide the most accurate 
adjustment, GM did not believe that manual 
adjustments would always be necessary. GM stated 
that, in most instances, use of the automatic brake 
adjustment feature in accordance with the manu- 
facturer's recommendations would provide ade- 
quate adjustment. 

NHTSA was persuaded by this comment. 
Accordingly, the SNPRM proposed that brakes 
shall be adjusted in accordance with the manufac- 
turer's recommendations. If a vehicle manufac- 
turer recommended manual adjustment for its 
brakes, the brakes would be so adjusted. Alterna- 
tively, if the manufacturer recommended that the 
brakes be inspected and adjusted only if necessary, 
that recommendation would be followed. If the 



PART 571; S105-PRE 91 



inspection showed that no adjustment to the brakes 
was necessary, none would be performed. 

Third, several commenters to the NPRM ob- 
jected to the proposed requirement to prohibit 
deactivation of automatic brake adjusters during 
testing for heavy vehicle's brake performance. 
These commenters argued that there was no valid 
reason to treat these heavy duty vehicles any dif- 
ferently than vehicles with GVWR's of 10,000 
pounds or less. Since the lighter vehicles are 
allowed to deactivate automatic brake adjusters 
during testing, heavier vehicles should be offered 
the same option, according to these commenters. 

NHTSA agreed with the implicit point of these 
comments that the reasons for and against per- 
mitting deactivation of automatic brake adjusters 
apply equally to all vehicles equipped with such 
devices, regardlessof vehicle weight, size, or type. 
Since this rulemaking addresses only the question 
or heavy duty vehicles and the agency did not 
think it appropriate to address the deactivation of 
automatic brake adjusters in a piecemeal fashion, 
the SNPRM announced that the issue would be 
addressed in a separate rulemaking. Hence, this 
rulemaking no longer addresses the issue of deac- 
tivation of automatic brake adjusters. 

In response to the SNPRM, 16 comments were 
submitted by 13 different commenters. All these 
comments were considered in connection with this 
final rule, and the most significant are discussed 
below. 

Final Rule 

Burnish Procedures 

The SNPRM asked for comments on four alter- 
native burnish procedures. In the SNPRM, the 
agency explained that its desired goal was to 
establish burnish procedures which represent 
driving conditions that would be encountered in 
normal use and which are fair for both types of 
brake systems (i.e., disc and drum brakes) while 
favoring neither. 50 FR 21315. Each of the four 
alternative procedures set forth in the SNPRM 
was evaluated to see how well it achieved this goal. 

The approach suggested by Motion Control in 
its comments on the NPRM was to eliminate the 
maximum temperature requirements during 
burnish and simply run the snubs as specified in 
Table IV of Standards No. 105 and 121. None of 
the commenters to the SNPRM supported this 
approach. Lucas Industries Inc. (Lucas) stated 
that this approach would cause drum brakes to 



exceed 550° F in some circumstances during the 
burnish. Such temperatures would, according to 
Lucas, degrade the brakes' performance in subse- 
quent tests. Chrysler agreed with Lucas, stating 
that an overly severe burnish can create excessive 
brake temperatures that substantially degrade or 
destroy the friction characteristics of the brake 
liningmaterial. Accordingly, Chrysler urged that 
this approach not be adopted. The Bendix Div- 
ision of Allied Automotive (Bendix) comment was 
substantially similar to Chrysler's on this alterna- 
tive. Ford, IH, and General Motors commented 
that this alternative should not be adopted because 
it would not be representative of normal condi- 
tioning. 

Motion Control itself stated that its suggested 
alternative would not be representative of normal 
brake conditioning and should not be adopted. 
However, Motion Control commented that the 
alternative would be acceptable if modified to 
require four 40-20 mph snubs followed by one 
60-20 mph snub, repeated one hundred times for a 
total of 500 snubs. In support of this position, 
Motion Control tested a vehicle with front disc 
brakes and rear drum brakes according to this 
proposed modification. The testing showed that 
the front disc brakes would experience tempera- 
tures of 820° F during such burnish, while the 
rear drum brakes would be heated to 560° F at the 
end of this testing. 

The agency agrees with the commenters that 
stated that the Motion Control approach as set 
forth in the SNPRM could potentially damage the 
brakes. Accordingly, such an approach would not 
satisfy the goal of establishing burnish procedures 
that are fair for both disc and drum brakes, nor 
would it be representative of the conditions 
encountered in normal driving. Therefore, this 
approach was not adopted in this final rule. 

The Ford approach received some support in 
the comments. As noted above, the Ford approach 
set forth in the SNPRM would retain the 550° F 
temperature limitation for drum brakes during 
the burnish, but would eliminate temperature 
restrictions for disc brakes. Lucas supported this 
alternative, contending that it would burnish 
drum brakes on disc-drum combination vehicles 
under the same conditions as drum brakes would 
be burnished on vehicles using only drum brakes. 
Motion Control also stated that this alternative 
was the best for vehicles that used disc and drum 
brakes. Abex Corporation (Abex) stated that they 
supported the Ford approach, if the agency were 
going to amend the burnish procedures. Flxible 



PART 571; S105-PRE 92 



Corporation (Flxible) stated that brake tempera- 
tures in excess of 500° F cook the lining resin in 
drum brakes and reduce their performance. 
Because of this, Flxible stated that any alternative 
that retained such a limit for drum brake burnish 
was acceptable, including the Ford approach. 

On the other hand, Chrysler, IH, Bendix, GM, 
and the Motor Vehicle Manufacturers Association 
(M VMA) opposed the Ford approach. These com- 
menters believed that no temperature limits dur- 
ing the burnish of vehicles using only disc brake 
systems would potentially damage the disc brakes. 
Additionally, these commenters did not believe 
that this burnish procedure would be representa- 
tive of normal driving. Ford itself agreed that 
some temperature limits should be added for disc 
brakes during the burnish, and suggested that its 
approach be adopted with an upper limit of 800° F 
for disc brakes. Both Bendix and MVMA com- 
mented that they would support the Ford ap- 
proach, if a temperature limitation for disc brakes 
were added. 

The approach suggested in the NPRM also 
received some support in the comments. Under 
this approach, vehicles would be burnished ac- 
cording to the schedule specified in Table IV, with 
a temperature limitation of 550° F for the hottest 
brake. However, if this temperature limitation 
were exceeded during the 40 to 20 mph snubs, all 
the remaining snubs would be run from 40 to 20 
mph without regard to temperature. Chrysler 
stated that there was no need to change the bur- 
nish procedures, but if they were to be changed, 
the approach suggested in the NPRM was the best 
of the four alternatives listed in the SNPRM. IH 
commented that the NPRM's approach was the 
only acceptable alternative offered in the SNPRM. 
This belief was based on that approach giving the 
higher temperatures necessary to properly condi- 
tion truck brakes and preserving the data history 
from compliance testing for the past 12 years. 

However, Lucas opposed this approach, because 
rear drum brakes on a disc/drum vehicle would 
not be sufficiently conditioned when the front disc 
brakes reached a temperature of 550° F. Motion 
Control raised the same objection, and also stated 
that this approach would not be representative of 
normal conditioning, since it would not allow 60- 
20 mph snubs on disc/drum vehicles. Bendix 
opposed this approach, arguing that it would not 
adequately condition the front disc brakes on a 
vehicle using only disc brakes. 

This final rule does not adopt either the Ford 
approach (limiting drum brake temperatures to 



550° F) or the NPRM approach (limiting the 
hottest brake temperature to 550° F), because the 
agency has concluded that the brake temperatures 
that would be generated under either of these 
approaches would not be representative of the 
brake temperatures generated during normal 
driving conditions in the case of drum brake 
systems. 

NHTSA has conducted a series of brake 
temperature tests for both hydraulically braked 
vehicles (DOT HS 806 860) and air braked vehicles 
(DOT HS 806 738) with gross vehicle weight 
ratings in excess of 10,000 pounds. These vehicles 
were driven in downtown traffic through Colum- 
bus, Ohio, and on the highways around that city. 
During this testing, the maximum temperatures 
measured for drum brakes were 410° F for one 
hydraulically braked vehicle and 350° F for the 
other hydraulically braked vehicle. The maximum 
temperature measured for drum brakes on air 
braked vehicles was 418° F. It should be noted 
that these maxima were measured for the rear 
axle of the tractor, and that the maximum 
temperatures measured for the other axles were 
significantly lower. Additionally, all of these 
maxima were recorded during the urban driving 
part of the testing. The brake temperatures 
measured on the highways were generally about 
100° F less than the brake temperatures measured 
on the streets and roads of Columbus. These 
findings indicate that a burnish procedure that 
allows drum brakes to be heated to 550° F cannot 
be said to be representative of normal driving 
conditions. 

Moreover, the findings in the NHTSA testing 
confirmed past research about brake tempera- 
tures. The University of Michigan Transportation 
Research Institute prepared a 1982 report entitled 
"Retarders for Heavy Vehicles: Phase II Field 
Evaluations." This report measured the average 
brake temperature for the drive axle of the tractor 
on five axle tractor-semitrailer combinations. This 
axle experienced the highest brake temperatures 
in the aforementioned NHTSA testing in Colum- 
bus, Ohio. These brake temperatures were mea- 
sured after the vehicles had made a descent of the 
fairly long grades on US 40 and US 48 in the 
westernpartof Maryland. Under these demanding 
conditions, the average brake temperature on the 
tractor drive axles was less than 350° F. 

Another 1982 report was prepared by Systems 
Technology Incorporated, entitled "The Develop- 
ment and Evaluation of a Prototype Grade Severity 
Rating System" (Report No. FHWA/RD-81/185). 



PART 571; S105-PRE 93 



This report also measured brake temperatures for 
five axle tractor-semitrailer combinations de- 
scending a grade. In this case, the grade was "the 
Grapevine" south of Bakersfield, California, on 
US 5. This is a well-known grade that features an 
average grade of 5.35 percent for 5.1 miles and 
presents heavy vehicle brakes with extremely 
demanding conditions. The brake temperatures 
of 25 vehicles were measured at the bottom of this 
grade. Even including the one vehicle that was a 
"runaway" because its brakes overheated, the 
average brake temperature for these vehicles was 
about 400° F. 

Given these consistent research findings about 
the temperatures to which drum brakes are 
subjected during normal driving, the agency 
concludes that a burnish that subjects drum 
brakes to significantly higher temperatures cannot 
be said to be representative of normal driving 
conditions. By allowing the drum brakes to be 
heated to temperatures well in excess of those 
encountered during normal driving, the burnish 
procedures would ideally condition the drum 
brakes. However, the agency is more interested in 
the braking capability of vehicles when the brakes 
are in the condition they are most likely to be when 
used on the roads than in the maximum braking 
capability of a braking system if the brakes are 
ideally conditioned. Since neither the Ford ap- 
proach nor the approach set forth in the NPRM 
would be representative of normal brake condi- 
tioning, neither approach has been adopted in this 
rule. 

In the comments, only Ford submitted data to 
support its contention that drum brakes would 
experience temperatures near 550° F under 
normal driving conditions. Ford tested a fully 
loaded vehicle through the traffic of downtown 
Detroit, Michigan. This vehicle was hydraulically 
braked with a disc s^'stem on the front axle and 
drum brakes on the rear. Ford stated that the 
maximum temperature measured for the drum 
brakes was 459° F. Ford also submitted data 
measuring the brake temperatures for air braked 
vehicles driving through the mountainous part of 
Arizona. The maximum temperature measured 
for the drum brakes over this road was 507° F. 
However, Ford did not provide measurements of 
the initial brake temperatures or average brake 
temperatures or any other information that would 
allow the agency to further analyze the Arizona 
test data. 

After considering the data submitted by Ford, 
NHTSA concludes that those data support the 



agency's conclusion that burnish procedures that 
allow drum brakes to be heated to 550° F do not 
represent conditions that will normally be en- 
countered by vehicles in use. The Detroit testing 
showed what the prior research and the agency 
research had shown; i.e., drum brakes do not 
experience temperatures of 550° F under normal 
driving. With respect to the temperatures 
measured in the Arizona mountains, NHTSA 
does not doubt that it is possible to find grades 
long enough and severe enough to heat drum 
brakes to 500° F. However, the point of the 
burnish procedure is not to simulate every con- 
ceivable condition that the vehicle might ex- 
perience while in use. Instead, the burnish pro- 
cedure is intended to simulate a normal break-in 
for the vehicle's brakes. While such conditioning 
would improve the performance of the vehicle's 
brakes, the agency has no evidence that most, or 
even a significant number of, new vehicles are 
broken in by driving through rugged mountainous 
terrain. Accordingly, a burnish procedure that is 
intended to be representative of normal driving 
conditions should not be based on these abnormally 
high temperatures. 

The approach suggested by the NHTSA re- 
search, i.e., making 500 snubs from 40-20 mph, is 
the final approach about which the SNPRM 
sought comments. After considering the intended 
function of the burnish procedures and all the 
comments received during this rulemaking action, 
NHTSA has selected this approach as the burnish 
procedure to be used for vehicles with a GVWR 
greater than 10,000 pounds. By making a series of 
braking applications from speeds encountered by 
every vehicle, this procedure will be most 
representative of normal driving conditions. 
Further, this procedure allows the brakes to reach 
whatever temperatures they are designed to reach 
when driven in typical stop-and-go driving. Thus, 
any braking system design will be conditioned 
fairly under this approach. 

Among the commenters to the SNPRM, only 
Rockwell International (Rockwell) completely 
endorsed this approach. Rockwell cited three 
factors that favored this approach. These were: 

1. It would give a constant rate of energy input 
to the brakes throughout the burnish, thus 
reducing variability associated with the original 
burnish procedure; 

2. The schedule of energy input to the brakes 
would be in the center of most vehicle application 
duty cycles, as desired, thus producing a typical, 
real-world vehicle brake burnish and a cor- 



PART 571; S105-PRE 94 



respondingly realistic brake performance test; 
and 

3. It would give all brakes the same burnish 
schedule, regardless of brake design or type, and 
should give an adequate burnish to each type of 
brake. Thus, all brakes would be on equal footing 
before starting the performance testing. 

Renault USA Inc. (Renault) stated that it was 
"not sure" if this approach would give a sufficient 
burnish to brakes, especially when considering all 
of the vehicles to which this burnish procedure 
would apply. However, Renault asserted that the 
available data were not exhaustive, and recom- 
mended that the final rule give manufacturers the 
option of burnishing their brakes either under 
this approach or the approach set forth in the 
NPRM. 

Bendix stated that its air braked disc systems 
reach the 550° F temperature limitations under 
the current procedures, so all 500 snubs are run 
from 40 to 20 mph for these vehicles. Flxible made 
a similar comment for its air braked drum brake 
systems on buses. These comments suggest that, 
at least for these manufacturers' braking systems, 
the new burnish procedures would not change the 
burnish from that which is specified under the 
current procedures. 

NHTSA believes that another advantage of this 
approach is that it would not favor or disfavor any 
type of brake design. Whenever the burnish 
procedures include a maximum temperature 
limitation, brakes that are designed to operate 
nearest that temperature get a more extensive 
burnish than do brakes that are designed to oper- 
ate at either a higher or lower temperature. For 
example, this rulemaking proceeding was initiated 
because the 550° F temperature limitation results 
in an unrealistic burnish for vehicles with disc 
brakes or both disc and drum brakes. That is 
because disc brakes are designed to operate safely 
at significantly higher temperatures than are 
drum brakes. Thus, it is necessary to amend this 
temperature limitation to account for the higher 
temperatures generated by disc brakes. 

Additionally, Eaton Corporation (Eaton) noted 
in its comments that the air brake industry is in 
the process of converting from asbestos-based 
brake linings to non-asbestos brake linings on 
drum brake systems. These non-asbestos linings 
will generate different normal and safe maximum 
temperatures during brake applications than the 
asbestos-based linings currently offered. If a 
temperature limitation for the burnish procedure 



were specified in this rule, that limitation might 
need to be adjusted for various new brake linings 
and new brake systems, to account for changing 
characteristics. 

Such repetitive rulemaking should be avoided. 
It continually diverts agency time and resources 
from more productive use. More importantly, it 
denies the public the early introduction of new 
technology, not because of any safety-related 
issues, but because it takes significant periods of 
time to amend the Federal motor vehicle safety 
standards. 

For example, it is possible that a new design for 
braking systems would not be adequately or 
representatively conditioned by burnish at some 
specified maximum temperature, as a result of 
which the braking system would not satisfy the 
performance requirements of Standard Nos. 105 
or 121. However, such a braking system would 
fully comply with those requirements if it were 
burnished in a manner that represented the break- 
in it would get during normal driving. Until the 
burnish procedures were amended, this braking 
system could not be installed on these heavy 
vehicles. Its introduction would be delayed solely 
because the temperature-restricted burnish pro- 
cedures did not allow for the development of 
newer designs. NHTSA wants to avoid imposing 
such unnecessary impediments to the introduction 
of innovative systems. 

A burnish procedure that requires 500 snubs 
from 40-20 mph avoids this pitfall. Under such a 
procedure, any new design will be burnished to 
v.'hatever temperatures it is designed to experience 
during normal city driving. No additional rule- 
making is required to ensure that the new design 
receives as effective and representative a burnish 
as do existing designs. Such a burnish procedure 
allows manufacturers to test and introduce in- 
novative technologies without unnecessary and 
unintended delays. 

However, the vast majority of commenters to 
the SNPRM objected to this approach. NHTSA 
stated in the SNPRM that preliminary examina- 
tion of the results of 500 snubs from 40 to 20 mph 
indicated that such a burnish would expose all 
types of brake designs to the temperatures they 
would encounter in normal service without favor- 
ing any type of brake design. A number of com- 
menters at least indirectly questioned this state- 
ment. 

Lucas commented that this burnish procedure 
would not adequately burnish drum brakes on 



PART571;S105-PRE95 



some vehicles with low gross axle weight ratings. 
However, Lucas did not submit any data to sub- 
stantiate this claim. Motion Control stated that 
when it burnished a vehicle with disc/drum brakes 
under this approach, the rear drum brake tempera- 
ture was only 400° F. Motion Control asserted that 
this did not approach the necessary 500°-550° F 
for adequate burnish of these brakes. GM likewise 
stated that a vehicle with disc/drum brakes would 
not experience sufficiently high temperatures to 
adequately burnish either the front disc brakes or 
the rear drum brakes. GM also commented that 
this procedure would not adequately burnish 
certain all drum brake systems. Ford stated that 
its testing showed that burnish under this approach 
does not expose the brake linings of vehicles with 
disc/drum brakes to temperatures they would 
encounter in normal service. 

NHTSA is not persuaded by these comments. 
Contrary to the implicit assertions of these com- 
ments, the purpose of the burnish procedure is not 
to guarantee that the vehicle's brakes will be 
exposed to a certain temperature. The agency 
concedes that this new burnish procedure may not 
expose current designs of drum brakes to tempera- 
tures of 500° F. The fact that drum brakes will not 
be exposed to temperatures as high as they were 
under the old burnish procedure does not, however, 
show that this burnish procedure is not an adequate 
burnish. As noted above, the burnish procedure is 
only intended to simulate the break-in of the 
brakes under normal driving conditions. The 
burnish is not intended to ensure that brakes will 
be ideally conditioned as a result of being exposed 
to unusually high temperatures they will rarely 
encounter while in service on the roads. The 
agency's testing indicated that a burnish consisting 
of 500 snubs from 40 to 20 mph will in fact expose 
the vehicle brakes to the temperatures those 
brakes would experience during stop-and-go urban 
driving. This finding leads the agency to conclude 
that such a burnish procedure would fairly 
represent the condition of brakes on vehicles that 
are in use on the nation's roads. 

Only Ford submitted data to substantiate its 
assertion that this burnish procedure would not 
expose the brakes on vehicles with front disc 
brake systems and rear drum brake systems to the 
temperatures such brakes would experience in 
normal driving. These data were obtained from 
the aforementioned driving around the Detroit 
area. However, the agency does not agree with 
Ford's comment that its Detroit test shows that 
brakes would not be exposed to normal driving 



temperatures, and therefore would not be properly 
conditioned, during this burnish procedure. For 
the single vehicle that was used in the Detroit test, 
the rear drum brakes experienced average tempera- 
tures while driving around Detroit that were 
slightly less than the average temperatures 
measured during the burnish procedure. This fact 
supports the agency's conclusion that the burnish 
procedures set forth in this rule will expose the 
vehicle brakes to temperatures that are repre- 
sentative of the temperatures those brakes will 
experience in normal driving. 

The front disc brakes on this vehicle did expe- 
rience somewhat higher temperatures in the test 
than during the burnish procedure. However, disc 
brakes are often not as sensitive to burnish 
temperature as drum brakes. This is because the 
burnish temperature for disc brakes appears to 
have little effect on the torque output of the brakes 
after burnish, provided that the burnish tempera- 
ture reaches at least 500° F. In Appendices B, C, 
and F to NHTSA's research on hydraulically 
braked vehicles (DOT HS 806 8602-864), disc 
brakes on three different vehicles reached tem- 
peratures of 500°, 600°, and 700° F during bur- 
nish, but all showed comparable performance 
improvements after the burnish. Hence, even if 
the front disc brakes did not experience quite as 
high an average temperature during burnish as 
they did during urban driving, they did expe- 
rience sufficiently high temperatures during 
burnish to simulate the "break-in" process. 

Other commenters asserted a position which 
was somewhat contradictory to the above com- 
ments. Chrysler and Bendix were opposed to this 
burnish procedure, because it did not specify any 
maximum temperature to which the brakes could 
be exposed during burnish. These commenters 
stated that the burnish procedure had to specify 
some reasonable maximum temperature require- 
ment to avoid damaging the brakes. The agency 
would like to note that any brakes that are 
designed so that they will be damaged while 
making 40 to 20 mph snubs probably should not be 
installed on new vehicles regardless of any ap- 
plicable regulatory provisions. Regardless of the 
brake type, this burnish procedure will ensure 
that all brakes are exposed to whatever tempera- 
tures they will be exposed to during normal 
break-in when operated on the public roads. 

Ford, IH, and MVMA all stated in their com- 
ments that NHTSA's testing of a limited sample 
of vehicles over a single route does not adequately 
duplicate the range of brake lining temperatures 



PART 571; S105-PRE 96 



experienced by the large variety of vehicles with 
GVWR's over 10,000 pounds operating over all 
possible driving cycles. The agency disagrees 
with the suggestion that the sample of vehicles for 
the Columbus, Ohio, tests was not representative. 
This sample included vehicles with widely varying 
GVWR's and with all current combinations of 
brake systems. None of these commenters pointed 
to a particular vehicle weight class or braking 
system that was not included in this sample, and 
the agency believes that its sample was broad 
enough to adequately represent these vehicles. 

NHTSA agrees that there are driving cycles 
such as frequent driving on grades that would 
generate higher brake temperatures than city 
driving. However, the agency was not seeking to 
establish a burnish procedure to simulate the 
most demanding conditions these vehicles would 
face in the real world or a burnish procedure that 
ideally conditions all brake designs. Instead, the 
agency wants to establish a burnish procedure 
that simulates normal "break-in" for vehicle 
brakes. Stop-and-go city driving generates signif- 
icantly higher brake temperatures than highway 
driving, primarily because of more frequent brake 
applications. This type of driving was chosen as 
the one the burnish should simulate, because it is a 
demanding type of driving for all braking systems, 
and it is likely to be generally and frequently 
experienced by the braking systems on heavy 
vehicles. NHTSA concluded that a burnish pro- 
cedure based on city driving would expose vehicle 
brakes to temperatures they will encounter in the 
real world and represent the break-in for those 
brakes in the real world. A more demanding 
driving cycle would not be representative of normal 
break-in for the vast majority of vehicles on the 
road. A less demanding driving cycle would not 
expose the vehicle brakes to the conditions those 
brakes will encounter when in service. Therefore, 
the urban driving cycle was selected as the one the 
burnish should represent. 

Abex commented that this burnish procedure 
would pose an additional problem. According to 
this commenter, without brake temperature data, 
it will be difficult to ensure any consistency of 
burnish conditioning from one test to another. 
First, nothing about the new burnish procedure 
prevents manufacturers from recording brake 
temperature data if they wish to do so. Second, 
this procedure will yield a constant rate of energy 
input to the brakes throughout the test, because 
all of the braking applications will be from 40 to 
20 mph. That will ensure greater consistency of 



burnish conditioning from one test to another than 
the old burnish procedure. This is because the old 
burnish procedure was based on brake tempera- 
ture. As noted in the comments of GM, IH, 
MVMA, and others, the brake temperature fluc- 
tuates greatly during the burnish, rising as much 
as 300° F during a brake application. These sharp 
temperature rises make it very difficult to ensure 
consistent conditioning from one burnish to an- 
other, if maximum temperature is the controlling 
factor. 

Abex also commented that Standard No. 105 
includes 60 mph stopping distance requirements. 
Since the brakes will be tested for performance 
from 60 mph, Abex urged that the brakes should 
also be burnished from this speed. Motion Control 
made a similar comment. These comments are not 
persuasive. In both the preburnish and postburnish 
tests. Standard No. 105 specifies that vehicles 
with a GVWR greater than 10,000 pounds must 
stop from 60 mph in 388 feet. NHTSA notes that 
the service brake stopping distance requirements 
of Standard No. 105, to which both these com- 
menters referred, are not currently in effect for 
vehicles with a GVWR greater than 10,000 pounds. 
Even if the service brake stopping distance re- 
quirements were in effect for these vehicles, the 
braking performance is not required to improve 
after burnish. Since Standard No. 105 only re- 
quires that the brakes on these vehicles retain the 
effectiveness they had before burnish, there is no 
reason to subject the vehicles to repeated 60 mph 
snubs during the burnish. Given the current 
requirements of the standard, the result of per- 
mitting 60 mph snubs would appear to be to raise 
the brake temperatures to unrealistically high 
levels. 

Ford, GM, MVMA, and IH all commented to the 
effect that this new burnish procedure would 
lower the brake temperatures experienced by 
drum brakes during the burnish. According to 
these commenters, the lower temperatures would 
affect the static and dynamic performance of the 
brakes on the vehicles, which, in turn, would 
require a redesign of the brake systems on certain 
vehicles. 

Since this new burnish procedure more effec- 
tively simulates normal break-in of these vehicles' 
brakes while in service on the roads, the braking 
performance measured for those vehicles in the 
performance tests for Standards No. 105 and 121 
should now more accurately reflect the vehicles' 
braking performance while in service. The agency 
has no reason to believe that any vehicles currently 



PART571:S105-PRE97 



being produced will not comply with Standards 
No. 105or 121 after being burnished in accordance 
with these new procedures. Moreover, none of 
these commenters submitted data that supports 
their assertions. 

MVMA simply stated that certain vehicles' 
braking systems would have to be redesigned as a 
result of this new burnish procedure. Without 
some data and examples of specific vehicles, 
NHTSA was unable to analyze this comment 
further. GM stated that its analysis of Standard 
No. 121 compliance data for some of its air braked 
transit buses with drum brake systems would be 
insufficiently burnished under this new procedure. 
As a result, GM stated that the buses' postburnish 
stopping distance would be increased to a level 
unacceptable to GM. It should first be noted that 
the stopping distance requirements of Standard 
No. 121 applicable to air braked buses have been 
suspended. Hence, there are no stopping distance 
requirements currently in effect for air braked 
buses. Even if there were stopping distance 
requirements in effect for air braked buses, GM 
did not assert that its transit buses would not 
comply with those requirements of Standard No. 
121. Presumably GM meant to say that the per- 
formance of its buses would exceed the minimum 
performance requirements by a margin that was 
too small to be acceptable to GM. If a more 
representative burnish procedure results in GM's 
products not meeting GM's own product standards 
for the amount by which the product's performance 
should exceed the requirements of Standard No. 
121, any redesign of the buses' braking system 
would be a result of the GM product standards, not 
Standard No. 121. To the extent that this new 
burnish procedure more accurately represents 
the break-in those buses' brakes actually receive 
while in service, it would also give GM a more 
accurate representation of how well those brakes 
will perform while in service. If vehicle man- 
ufacturers are not getting an accurate repre- 
sentation of how their vehicle braking systems 
perform when used by the public from the current 
burnish procedure, that is yet another reason to 
adopt the new burnish procedure. 

Ford submitted data purporting to show that 
one of its vehicles with hydraulic disc and drum 
brakes would no longer comply with the require- 
ments of section S7.9 of Standard No. 105, if it 
were burnished according to this new procedure. 
That section of Standard No. 105 requires the 
vehicle to stop from 60 mph in a specified distance 



even if the vehicle experiences a partial service 
brake failure. With respect to vehicles with a 
GVWR greater than 10,000 pounds. Table II of 
Standard No. 105 specifies that such vehicles 
must stop in 613 feet from 60 mph with a partial 
service brake failure. Ford submitted data show- 
ing that the longest stopping distance for its vehi- 
cle was 737.5 feet and the average stopping dis- 
tance was 626.3 feet. 

However, Ford did not note that S7.9 requires 
only that the vehicle stop in 613 feet in one of the 
four required stops with a partial service brake 
failure. Since Ford's longest stopping distance for 
this condition was 737.5 feet and the average stop- 
ping distance for the four stops was 626.3 feet, the 
average of the other three stopping distances was 
589.23 feet. This average is well within the re- 
quired 613 feet maximum distance. Therefore, 
NHTSA does not believe that Ford's data support 
its asserted compliance problems. 

To the extent that Ford's data were intended to 
show a reduction in the after burnish performance 
capabilities of the truck to a level unacceptable to 
Ford, the agency responds in the same way as it 
did to GM's comment on this point. That is, the 
data show that the vehicle complies with Standard 
No. 105. If the amount by which the vehicle 
exceeds that minimum performance requirement 
is unacceptable to Ford, any redesign of the 
braking system is a result of Ford's product 
standards, not Standard 105. Further, if the new 
burnish procedure gives Ford a more accurate 
representation of how well its braking system 
performs when in service on the public roads, that 
fact supports the agency's decision to implement 
the new burnish procedures. 

IH commented that the changed burnish pro- 
cedure would cause it to have compliance problems 
with section S5.6.1 of Standard No. 121. That 
section requires that the static retardation force 
produced by the parking brakes alone shall be 
such that the quotient of the static retardation 
force/GVWR is not less than 0.14. According to 
IH, under the current burnish procedure, this 
requirement means that it can use parking brakes 
on just one axle of a truck tractor unless the 
GVWR of the tractor is greater than 56,000 
pounds. For tractors with a GVWR over 56,000 
pounds. International Harvester must use parking 
brakes on two axles. However, International 
Harvester stated that under the new burnish 
procedure, it would have to install parking brakes 
on two axles of tractors with a GVWR over 46,000 



PART571;S105-PRE98 



pounds. According to the commenter, this will 
add costs and system complexity to tractors with 
GVWR's between 46,000 and 56,000 pounds. 

International Harvester did not provide enough 
information for the agency to fully evaluate this 
comment. Most notably, the comment does not 
indicate whether the entire Standard No. 121 test 
sequence was run prior to the parking brake force 
measurements. Agency compliance testing of the 
parking brakes is conducted only after conduct- 
ing service brake testing. If the 60 mph loaded 
vehicle service brake tests, which help condition 
the brakes, were not run prior to the parking 
brake force measurements, the parking brake 
force measurements are probably lower than they 
would have been had the complete Standard No. 
121 compliance testing been conducted. 

Assuming that International Harvester did 
conduct the full Standard No. 121 testing for this 
vehicle, the agency has no reason to believe that 
parking brakes should not be required on two 
axles of tractors with a GVWR of more than 
46,000 pounds. If the International Harvester 
data are correct, the parking brakes on one axle of 
such tractors cannot provide a retarding force of 
0.14 even when properly adjusted, if the brake 
linings are conditioned as they most likely would 
be when in service. A retarding force of 0.14 is 
roughly the equivalent of a 14 percent grade. If 
NHTSA accepts the commenter's conclusion that 
the new burnish procedure results in a 17 percent 
reduction in parking brake force, and the new 
burnish procedure more accurately represents 
the normal condition of brake linings in use on the 
roads, the parking brakes of some tractors with a 
GVWR of 55,000 pounds now being used on the 
public roads are only capable of holding on an 1 1.7 
percent grade. If true, this comment raises con- 
cerns as to how well the parking brakes perform 
for vehicles currently in service. It also lends sup- 
port to the agency's decision to implement burnish 
procedures that are more representative of the 
conditioning brakes get while in service. 

Eaton, IH, and M VM A commented that a change 
to the burnish procedures should not be adopted, 
because any change would make obsolete 12 years 
of accumulated test data. These comments do not 
directly challenge the agency's conclusion that the 
new burnish procedures will be far more repre- 
sentative of the break-in that most brakes get 
while in service on the highways. Neither does this 
reasoning challenge the agency's conclusion that 
this new burnish procedure will not favor any new 
or future brake system designs. Instead, these 



comments urge the agency to retain a temperature- 
restricted burnish procedure because that is what 
the agency has used in the past. NHTSA does not 
agree that it should continue to require a burnish 
procedure that favors older brake designs and is 
not representative of real-world conditioning of 
brakes, simply because it has done so in the past. 
Indeed, it appears to be a far more responsible 
course of action to acknowledge the problems of 
the old burnish procedure and try to correct those 
problems in a new burnish procedure at a time 
when there are no service brake stopping distance 
requirements in effect for hydraulically braked 
heavy trucks subject to Standard No. 105, and 
when there are )io service or emergency brake 
stopping distance requirements in effect for air 
braked vehicles subject to Standard No. 121. 

Notwithstanding the agency's disagreement 
with the direct point of these comments, NHTSA 
believes that the implicit point of these comments 
is convincing. The agency reads these comments 
to imply that NHTSA ought to allow the manufac- 
turers sufficient time to develop a new data bank 
using the new burnish procedures before mandat- 
ing that vehicles be certified as complying with 
braking standards that incorporate these new 
burnish procedures. NHTSA believes that this is 
a legitimate concern that must be addressed in 
this rulemaking. The same point was indirectly 
raised in the International Harvester and MVMA 
comments that these new burnish procedures will 
require retesting of some vehicle's braking capa- 
bilities to ensure continuing compliance with the 
applicable standard. 

The agency agrees that it must fully consider 
theeconomic impactsof anew burnish procedure, 
and should minimize those impacts when that is 
possible. This is particularly true in this rulemak- 
ing. This new burnish procedure is not intended to 
impose additional performance requirements for 
heavy vehicles in response to a demonstrated 
safety problem. Rather, the new burnish proce- 
dure is intended to ensure that vehicles are tested 
for compliance with the existing performance 
requirements when the brakes are conditioned to 
the same extent that brakes are typically condi- 
tioned when used by the public on our nation's 
roads, and to eliminate the current disfavoring of 
new brake designs from the burnish procedures. 
Given these purposes, the agency can and should 
minimize the economic impacts associated with 
the transition to a new burnish procedure. 

Accordingly, this rule includes a transition 
period until September 1, 1993. During this period, 



PART 571; S105-PRE 99 



heavy vehicles may be burnished under the old or 
new burnish procedures, at the manufacturer's 
option, before compliance testing. For this transi- 
tion period, the old burnish procedures have been 
modified in accordance with the approach taken 
in the NPRM for this rulemaking. That is, vehi- 
cles will be subjected to 500 snubs for the burnish 
according to the schedule set forth in Table IV. 
However, if the temperature of the hottest brake 
exceeds 550° F, the snubs shall be adjusted to a 
lower speed as necessary to maintain a hottest 
brake temperature of 550° F. If the hottest brake 
temperature exceeds 550° F at the lowest snub 
condition set forth in Table IV (40 to 20 mph), the 
remainder of the snubs shall be run from 40 to 20 
mph without regard to brake temperature. This 
change has been made to accommodate disc brake 
systems, which are designed to operate safely at 
temperatures in excess of 550° F. Since this prob- 
lem was the issue this rulemaking was initiated to 
address, it is appropriate for the agency to address 
this problem now instead of waiting for the end of 
the transition period. 

The agency believes that this transition period 
will effectively minimize any adverse economic 
impacts associated with the change to a new 
burnish procedure. It will allow manufacturers to 
specifically identify any vehicles whose braking 
system would not comply with the performance 
requirements of Standard Nos. 105 and 121 using 
the new burnish procedures. If only a few isolated 
vehicles are affected, the transition period will 
give the manufacturers sufficient time to make 
appropriate design changes to those vehicles. If, 
on the other hand, the new burnish procedures 
will necessitate major design changes to almost all 
vehicles now in production, or result in some other 
adverse economic consequences of which the 
agency is now unaware, the transition period 
would allow the agency time to make appropriate 
regulatory changes to avert such unintended eco- 
nomic impacts. Further, this transition period 
would enable the manufacturers to gather a data 
bank of testing under the new burnish procedures 
before those procedures are mandated, asurged 
in the Eaton, IH, and MVMA comments. 

Tractor-Trailer Loadi)tg During Burnish 

As noted above, the SNPRM proposed that the 
unbraked trailer used to test the braking perform- 
ance of truck tractors would be loaded so that the 
combined weight of the tractor-trailer combi- 
nation is equal to the GVWR of the tractor. Abex 
supported this proposal. 



However, Ford, IH, Bendix,and MVMA opposed 
this proposal in their comments. They explained 
that their objection was based on the fact that the 
proposed change appears to require the use of a 
trailer during the testing of a truck tractor's 
brakes. These commenters stated that most trac- 
tor manufacturers use load racks, instead of trail- 
ers, during such testing. These load racks simu- 
late the weight that a trailer would place on the 
tractor. The commenters stated that a new re- 
quirement that tractor manufacturers use actual 
trailers during testing was unnecessary. Since the 
commenters believed that the agency's intent was 
to prevent overloading of trailers (/trailers were 
used for testing, they suggested that the language 
of the rule be amended to more accurately reflect 
such intent. 

NHTSA believes that these comments reflect a 
misunderstanding of the compliance test proce- 
dures set forth in the Federal motor vehicle safety 
standards. The use of the word "shall" in the 
compliance test procedures means that the agency, 
and no other party, is required to use an unbraked 
flatbed semitrailer during its compliance testing 
for truck tractors. When specifying its compliance 
testing procedures in any of the safety standards, 
the agency is required by the National Traffic and 
Motor Vehicle Safety Act ["the Safety Act"; 15 
U.S.C. 1381 et seqjto specify those procedures in 
"objective terms." 15 U.S.C. 1392(a). One aspect of 
the requirement that a compliance test procedure 
be stated in objective terms is that the procedures 
must, to the maximum extent possible, eliminate 
potential sources of variability in test results. 

In this particular case, the agency has no reason 
to believe that load racks do not provide an 
accurate simulation of the loading imposed on a 
truck tractor by a trailer during the burnish 
procedures, because it is the total load that effects 
the burnish and not the load distribution (provided 
that each axle is loaded sufficiently to protect 
against wheel lock and the vehicle is not equipped 
with a load proportioning valve). However, the 
agency also has no data to support its belief that 
load racks would yield burnish results identical to 
those that are obtained with an unloaded trailer. 
Hence, a provision that the agency could use load 
racks in its compliance testing might introduce 
variability into these standards. The only way to 
learn whether the use of load racks during the 
burnish procedures would introduce variability 
into the standards would be for the agency to 
spend a substantial amount of its research time 
and dollars investigating this subject. NHTSA 
believes that such an expenditure of its research 



PART 571;S105-PRE 100 



efforts for a project that would have no obvious 
safety benefits would be unjustified. Therefore, 
the agency has chosen to draft this final rule so 
that it does not introduce any potential source of 
variability, by simply specifying that an unbraked 
flatbed semitrailer will be used by NHTSA in its 
compliance testing. 

This decision need »ot increase testing costs for 
the manufacturers. It is worth noting that man- 
ufacturers are not even required to conduct test- 
ing before certifying that these vehicles comply 
with these standards, provided that they exercise 
"due care" in making such certifications, as pro- 
vided in section 108(a)(1)(C) of the National Traffic 
and Motor Vehicle Safety Act [15 U.S.C. 
1397(a)(1)(C)]. If manufacturers choose to conduct 
testing in accordance with the compliance test 
procedures, they are free to simulate any or all 
parts of the test procedures. If the agency tests 
reveal a noncompliance, the agency's consideration 
of the appropriateness of a civil penalty will 
necessarily include the issue of whether such 
simulations are reasonable enough to satisfy the 
"due care" standard. 

In this particular case, let us assume that a 
truck tractor manufacturer has chosen to conduct 
testing prior to certifying compliance and has 
employed a load rack during the burnish proce- 
dure. Let us also assume that the manufacturer's 
testing showed that the tractor complied with the 
standard and the manufacturer so certified. If 
NHTSA should subsequently conduct compliance 
testing for the tractor, the agency would burnish 
the tractor using a trailer. Finally, let us assume 
that the testing showed that the individual tractor 
being tested did not comply with the braking 
standards. 

In these circumstances, NHTSA would follow 
its longstanding and well-known enforcement 
policy of notifying the manufacturer of the agency's 
test results and asking the manufacturer for 
further information. In response, the manufac- 
turer would provide the results of its compliance 
testing to the agency, together with its reasons for 
concluding that a load rack is a reasonable simula- 
tion for a trailer during burnish. To support an 
argument that its own tests actually demonstrate 
compliance or to show that it exercised due care in 
its substitution of a load rack for a trailer during 
burnish, the manufacturer would also submit the 
bases for its conclusion that a load rack is a 
reasonable simulation of a trailer for the purposes 
of the burnish. 

At this point, the agency would carefully ana- 



lyze the manufacturer's response. If the agency 
concludes that the difference in test results can be 
explained to the agency's satisfaction, that the 
agency's results do not indicate an unreasonable 
risk to safety, and that the manufacturer's tests 
were reasonably conducted and were in general 
conformity with the standard, the agency would 
consider whether its own test results would sup- 
port a determination of noncompliance. These 
enforcement practices have long been a matter of 
public record. 

Of course, a manufacturer that could show that 
it exercised due care in making its certification 
would still be subject to the statutory obligation to 
recall and remedy its vehicles that do not conform 
to the requirements of Standard Nos. 105 or 121, 
assuming that the agency or the manufacturer 
makes a determination that the vehicles did not 
comply with the applicable standard. However, 
this same obligation would apply even if the 
manufacturer had conducted full compliance test- 
ing and used a flatbed semitrailer to burnish its 
tractors. 

Thus, the agency does not believe that the 
amendment requiring NHTSA to burnish tractors 
using flatbed semitrailers necessarily puts 
manufacturers at risk of a civil penalty solely 
because they chose to use load racks during 
tractor burnish, /^x/css the manufacturer had no 
reason to believe that a load rack was an adequate 
simulation of a trailer. If this were the case, the 
manufacturers' comments that they should be 
allowed to continue using load racks during bur- 
nish would have no merit. However, NHTSA does 
not understand the commenters to be making 
such an assertion, and has no reason to question 
the representativeness of load racks during the 
burnish procedures. Therefore, this rule adopts 
the tractor loading requirements during burnish 
that were proposed in the SNPRM. 

In this same vein, the agency would like to point 
out that this final rule does not adopt a proposed 
change to section S6 of Standard No. 121. That 
proposed change would have allowed final stage 
manufacturers to "demonstrate compliance" with 
Standard No. 121, if the final stage manufacturer 
adhered to the instructions provided with the 
vehicle by the incomplete vehicle manufacturer 
and any intermediate stage manufacturer of the 
vehicle. The proposed language erroneously con- 
veys the impression that the statutory and regula- 
tory requirements for notification and remedy of 
noncomplying vehicles would not be applicable if 
a final stage manufacturer could show that it had 



PART 571; S105-PRE 101 



adhered to the instructions provided with the 
incomplete vehicle by the incomplete vehicle 
manufacturer and any intermediate stage man- 
ufacturers. 

What the proposed language was intended to do 
was to make clear that a final stage manufacturer 
can demonstrate compliance with the statutory 
requirement that it exercise due care in making 
certifications of compliance with Standard No. 
121, if the final stage manufacturer can show that 
it adhered to the instructions provided with the 
incomplete vehicle by the incomplete vehicle 
manufacturer and any intermediate stage man- 
ufacturers. However, such a provision is redun- 
dant. 49 CFR §567.5 and 49 CFR §568.6 already 
permit the final stage manufacturer that has 
adhered to the instructions provided with the 
incomplete vehicle to so state, and rely on its 
adherence to the Instructions provided with the 
incomplete vehicle as the basis for its certification 
of the vehicle. Since these regulatory requirements 
make clear that any final stage manufacturers 
satisfy "due care" responsibilities for certification 
when they adhere to the instructions furnished 
with the incomplete vehicle, it is unnecessary to 
add a similar requirement to Standard No. 121. 
Therefore, this proposed change is not incorporated 
in this final rule. 

Brake Adjustments During Burnish 

The SNPRM proposed that the brakes shall be 
adjusted in accordance with the manufacturer's 
recommendations at specified intervals during 
the burnish procedure. As explained in the 
SNPRM, if a manufacturer recommends that 
brakes be inspected first and adjusted only if 
necessary, that recommendation would be fol- 
lowed. If the inspection were to show that no 
adjustment was necessary, none would be per- 
formed. 

This change was proposed because past inter- 
pretations and preambles have repeatedly stated 
that brake adjustments are permitted during 
burnish. Since these adjustments are permitted, it 
is necessary that the compliance test procedures 
specify how often and when the adjustments will 
be made. Otherwise, the standards would incor- 
porate a potential source of variability, and would 
give rise to the problems described above in the 
Tractor-Trailer Loading During Burnish section. 

Ford commented that it had no objections to the 
brake adjustment provisions proposed in the 
SNPRM. MVMA commented that it agreed with 
the proposed brake adjustment provisions. 



However, Lucas disagreed with the proposal. It 
commented that brake adjustments should only 
be required during burnish if such adjustments / 
are necessary to obtain the specified rate of V 
deceleration during the burnish. The agency did 
not propose or intend to requ ire brake adjustments 
unless the manufacturer recommends them at 
that time. If the vehicle manufacturer recom- 
mends that the brakes be inspected and adjusted 
only if certain conditions exist, the brakes will not 
be adjusted unless those conditions exist. There- 
fore, if Lucas desires that its brakes not be 
adjusted unless certain conditions exist, it should 
recommend that the brakes be inspected and 
adjusted only if those conditions exist. Such a 
recommendation would accomplish Lucas's goal 
without making any change to the proposed require- 
ment. Hence, no change to the proposed language 
has been made in response to this comment. 

Abex also objected to this proposed requirement 
in its comments. Abex stated that regulating 
adjustments during burnish was, in its opinion, 
"unwarranted." The comment went on to state 
that, "We are not aware of any problems that have 
been encountered with the current procedure 
which does not control either the number of 
adjustments that can be made or the specific 
points during burnish where they can be made." / 
As explained above and in the SNPRM, the reason \ 
for proposing this requirement was to establish 
uniformity and specificity for the agency's com- 
pliance test procedures. The need for uniformity 
and specificity are sufficiently compelling in the 
agency's judgment to warrant these provisions. 

Abex continued by stating that many dyna- 
mometers have automatic controls, which means 
the manufacturers can conduct the burnish pro- 
cedures "essentially unattended." The commenter 
stated that this feature allows manufacturers to 
frequently conduct the dynamometer burnish 
through the night or during weekends. According 
to Abex, if the agency requires manufacturers to 
make adjustments at specified times and intervals, 
the requirement will slow up the burnish, increase 
labor costs, or both. 

As discussed above in the section on tractor- 
trailer loading during burnish, NHTSA is not 
requiring the manufactures to follow these proce- 
dures for any testing they choose to conduct. These 
are the procedures the agency will follow during 
its compliance testing. As long as the manufacturer 
exercises due care in connection with the testing it 
conducts, it would satisfy its statutory obligations 
in connection with certifications. Abex apparently I 
has reason to believe that brake adjustments are ^ 



PART 571;S105-PRE 102 



not necessary during dynamometer burnish, since 
it does not make such adjustments at present. 
Assuming that Abex's reasons are sufficient to 
establish that it exercised due care before cert- 
ifying that its brakes complied with this require- 
ment, or if Abex recommends no brake adjust- 
ments during burnish, Abex will not have to 
change its current testing practices under this 
new regulatory provision. If. on the other hand, 
Abex has insufficient reason for concluding that 
no brake adjustment is necessary during dyna- 
mometer testing, Abex should change its practice 
irrespective of any changes to the compliance test 
procedures. Therefore, the agency has concluded 
that the establishment of timing and frequency 
requirements for brake adjustment during burnish 
in the agency's compliance tests need not increase 
the costs or time required for any testing man- 
ufacturers choose to conduct. These requirements 
are adopted as proposed. 

Regulatory Imimcts 

A. Costs and Benefits to Manufacturers and 
Consumers. 

NHTSA has analyzed this rule and determined 
that it is neither "major" within the meaning of 
Executive Order 12291 nor "significant" within 
the meaning of the Department of Transportation 
regulatory policies and procedures. The main 
impact of this rule will be to provide burnish 
procedures that are more representative of the 
actual "break-in" that vehicles' brakes typically 
receive while in use on the nation's roads, without 
favoring any particular braking system design. 
As noted above, there are no stopping distance 
requirements currently in effect for service brakes 
on hydraulically braked vehicles, and no stopping 
distance requirements in effect for either service 
brakes or emergency brakes on air braked vehicles. 
Hence, these new burnish procedures will not 
affect certifications of compliance by manufac- 
turers of those braked systems. 

It is possible that the new burnish procedures 
could affect certifications of compliance with 
applicable stopping distance requirements for 
parking brake systems. The extent to which the 
changed burnish procedures will affect those 
certifications is uncertain. No commenter sub- 
mitted evidence that any complying parking brake 
systems will no longer comply as a result of the 
change in burnish procedures. To address this 
possibility, however, this rule provides for a five 
year transition period to the new burnish pro- 



turers may continue to certify vehicles using the 
old burnish procedures. At the same time, the 
manufacturers can can experience with the 
effects of the new burnish procedure's effect on 
the performance of their braking systems. The 
transition period will allow time for the man- 
ufacturers to make appropriate changes to their 
braking systems in an orderly fashion, and at 
minimal cost. Because the agency anticipates that 
this rule will have only minimal economic im- 
pacts, it has not prepared a full regulatory 
evaluation. 



B. Small Business Impacts. 

The agency has also considered the impacts of 
this rule as required by the Regulatory Flexibility 
Act. I hereby certify that this rule will not have a 
significant economic impact on a substantial 
number of small entities. Few of the truck tractor 
manufacturers affected by this burnish procedure 
are small entities. Many of the trailer manufac- 
turers may qualify as small entities. However, 
this rule will not significantly increase the pro- 
duction or certification costs for those manufac- 
turers that do not qualify as small entities. There 
are currently no stopping distance requirements 
applicable to trailers. Thus, these new burnish 
procedures will not make it more difficult for 
small manufacturers of trailers to certify com- 
pliance with service brake stopping distance 
requirements. Standard 121 specifies parking 
brake requirement for air braked trailers, but 
trailer manufacturers, except possibly the largest 
trailer manufacturer who also makes brakes, 
usually depend on their brake manufacturer to 
provide the information necessary for certification 
to the parking brake requirements. Accordingly, 
any inceased certification burden for parking 
brake systems that might be associated with this 
new burnish procedure would be borne by brake 
manufacturers (which generally do not qualify as 
small entities) and the large trailer manufacturers. 
Small organizations and governmental jurisdic- 
tions will be affected as purchasers of these 
vehicles. However, the cost impacts of this rule 
will be minimal, as described above. Accordingly, 
a regulatory flexibility analysis has not been 
performed. 

C. Environmental Impacts 

NHTSA has considered the environmental im- 
plications of this rule, in accordance with the 



PART 571;S105-PRE 103 



National Environmental Policy Act, and deter- 
mined that it will not significantly affect the 
human environment. Accordingly an environ- 
mental impact statement has not been prepared. 

List of Subjects in Jt9 CFR Part 571 

Imports, Motor vehicle safety, Motor vehicles. 
Rubber and rubber products, Tires. 

In consideration of the foregoing, 49 CFR 
571.105, Hydraulic Brake Systems, and 49 CFR 
571.12, A ir Brake Systems, are amended as follows: 

PART 571 - FEDERAL MOTOR VEHICLE 
SAFETY STANDARDS 

The authority citation for Part 571 continues to 
read as follows: 

Authority: 15 U.S.C. 1392, 1401, 1403, 1407; 
delegation of authority at 49 CFR 1.50. 

§571.105 Standard No. 105: Hydraulic brake 
systems. 

1. S7.4.2 of §571.105 is amended by revising 
S7.4.2.1 and S7.4.2.2 to read as follows: 

S7.4.2 Vehicles with GVWR greater than 10,000 
pounds. 

S7 .i.2.1 Burnish. Vehicles manufactured before 
September 1, 1993, may be burnished according 
to the procedures set forth in S7. 4. 2. 1(a) or 
S7. 4. 2.1(b) of this section, at the manufacturer's 
option. Vehicles manufactured on or after Septem- 
ber 1, 1993, shall be burnished according to the 
procedures set forth in S7. 4. 2. 1(b) of this section. 

(a) Burnish the brakes by making 500 snubs at 
10 fsps in the sequence specified in Table IV and 
within the speed ranges indicted. Except where 
an adjustment is specified, after each brake ap- 
plication accelerate to the next sped specified and 
maintain that speed until making the next brake 
application at a point 12 mile from the initial point 
of the previous brake application. If a vehicle 
cannot attain any speed specified in 1 mile, 
continue to accelerate until the specified speed is 
reached or until the vehicle has traveled 1.5 miles 
from the initial point of the previous brake ap- 
plication, whichever occurs first. If during any of 
the brake applications specified in Table IV the 
hottest brake reaches 550° D, make the remainder 
of the 500 brake applications from that snub 
condition, except that a higher or lower snub 
condition shall be followed (up to the 60 mph 
initial speed) as necessary to maintain a hottest 
brake temperature of 500° F ± 50° F. However, if 
at a snub condition of 40 to 40 mph, the temperature 
of the hottest brake exceeds 550° F, make the 
remainder of the 500 brake applications from that 



snub condition, without regard to brake temp- 
erature. The brakes shall be adjusted three times 
during the burnish procedure, in accordance with 
the manufacturer's recommendations after 125, 
250, and 375 snubs. 

TABLE IV 



Series Snubs 



Snub conditions (highest speed 
indicated, miles per hour) 



1 


175 


40-20 


2 


25 


45-20 


3 


25 


50-20 


4 


25 


55-20 


5 


250 


60-20 



(b) Burnish the brakes by making 500 snubs 
between 40 mph and 20 mph at a deceleration rate 
of lOpfps. Except where an adjustment is specified, 
after each brake application accelerate to 40 mph 
and maintain that speed until making the next 
brake application at a point 1 mile from the initial 
point of the previous brake application. If the 
vehicle cannot attain a speed of 40 mph in 1 mile, 
continue to accelerate until the vehicle reaches 40 
mph or until the vehicle has traveled 1.5 miles 
from the initial point of the previous brake 
application, whichever occurs first. The brakes 
shall be adjusted three times during the burnish 
procedure, in accordance with the manufacturer's 
recommendations after 125, 250, and 375 snubs. 

S7.4.2.2 Brake adjustment - post burnish. After 
burnishing, adjust the brakes in accordance with 
the manufacturer's recommendations. ***** 

2. S7.6 of §571. 105 is revised to read as follows: 
S7.6 First reburnish Repeat S7.4, except make 
35 burnish stops or snubs In the case of vehicles 
burnished in accordance with S7. 4. 2. 1(a) of this 
section, reburnish the vehicle by making 35 snubs 
from 60 to 20 mph, but if the hottest brake 
temperature reaches 500° F ± 50° F, make the 
remainder of the brake applications from the 
highest snub condition listed in Table IV that will 
maintain the hottest brake temperature at 50° F ± 
to° F. If at a snub condition of 40 to 20 mph, the 
temperature of the hottest brake exceeds 550° F, 
make the remainder of the 35 brake applications 
from that snub condition without regard to brake 
temperature. 
§571.121 Standard No. 121: Air brake systems. 



PART 571; S105-PRE 104 



3. S6 of §571.121 is revised to read as follows: 
S6 Cunditioiity. The requirements of S5 shall be 

met by a vehicle when it is tested according to the 
conditions set forth below, without replacing any 
brake system part or making any adjustments to 
the brake system except as specified. Except as 
otherwise specified, where a range of conditions is 
specified, the vehicle must be capable of meeting 
the requirements at all points within the range. 

4. S6.1 of §571.121 is amended by revising 
S6.1.1 and S6.1.8.1 to read as follows: 

S6.1 Road test conditions. 

S6.1.1. Except as otherwise specified, the vehicle 
is loaded to its gross vehicle weight rating, 
distributed proportionally to its gross axle weight 
ratings. During the burnish procedure specified 
in S6.1.8, truck tractors shall be loaded to their 
GVWR by coupling them to an unbraked flatbed 
semitrailer, which semitrailer shall be loaded so 
that the weight of the tractor-trailer combination 
equals the GVWR of the truck tractor. The load on 
the unbraked flatbed semitrailer shall be located 
so that the truck tractor's wheels do not lock 
duringburnish. ***** 

S6.1.8*** 

S6. 1.8.1. Vehicles manufactured before Septem- 
ber 1, 1993 may be burnished according to the 
procedures set forth in S6. 1.8. 1(a) or S6. 1.8. 1(b) of 
this section, at the manufacturers option. Vehicles 
manufactured on or after September 1, 1993 shall 
be burnished according to the procedures set forth 
in S6. 1.8. 1(b) of this section. 

(a) With the transmission in the highest gear 
appropriate for the series given in Table IV, make 
500 brake applications at a deceleration rate of 
lOfsps, or at the vehicles maximum deceleration 
rate if less than 10 fsps, in the sequence specified. 
Except where an adjustment is specified, after 
each brake application accelerate to the next 
speed specified and maintain that speed until 
making the next brake application at a point 1 
mile from the initial point of the previous brake 
application. If a vehicle cannot attain any speed 
specified in 1 mile, continue to accelerate until the 
specified speed is reached or until the vehicle has 
traveled 1.5 miles from the initial point of the 
previous brake application, whichever occurs first. 
If during any of the brake applications specified 
in Table IV the hottest brake reaches 550° F, 
make the remainder of the 500 brake applications 
from that snub condition, except that a higher or 
lower snub condition shall be used as necessary to 
maintain an after-stop temperatire of the hottest 



brake exceeds 550° F, make the remainder of the 
500 brake applications from that snub condition, 
without regard to brake temperature. The brakes 
shall be adjusted three times during the burnish, 
with each adjustment made in accordance with 
the manufacturer's recommendations. Any auto- 
matic pressure limiting valve is in use to limit 
pressure as designed, except that any automatic 
front axle pressure limiting valve is bypassed if 
the temperature of the hottest brake on a rear axle 
exceeds the temperature of the hottest brake on a 
front axle by more than 125° F. A bypassed valve 
is reconnected if the temperature of the hottest 
brake on a front axle exceeds the temperature of 
the hottest brake on a rear axle by 100° F or more. 

TABLE IV 

Series Snubs Snub conditions (highest speed 
indicated, miles per hour) 



40-20 
45-20 
50-20 
55-20 
60-20 



(b) With the transmission in the highest gear 
approprrate for a speed of 40 mph, 500 snubs 
between 40 mph and 20 mph at a deceleration rate 
of 10 fsps, or at the vehicle's maximum deceleration 
rate if less than 10 fsps. Except where an adjust- 
ment is specified, after each brake application 
accelerate to 40 mph and maintain that speed 
until making the next brake application at a point 
1 mile from the initial point of the previous brake 
application. If the vehicle cannot attain a speed of 
40 mph in 1 mile, continue to accelerate until the 
vehicle reaches 40 mph or until the vehicle has 
traveled 1.5 miles from the initial point of the 
previous brake application, whichever occurs first. 
Any automatic pressure limiting valve is in use to 
limit pressure as designed. The brakes shall be 
adjusted three times during the burnish procedure, 
in accordance with the manufacturer's recom- 
mendations, after 125, 250, and 375 snubs, and 
shall be adjusted after burnish in accordance with 
the manufacturer's recommendations. ***** 

5. S6.2.6 of §571.121 is revised to read as 
follows: 

S6.2 Dynamometer test conditions. ***** 



1 


175 


2 


25 


3 


25 


4 


25 


5 


250 



PART 571; S105-PRE 105 



S6.2.6. Brakes are burnished before testing as adjusted three times during the burnish pro- 
follows: Place the brake assembly on an inertia cedure, after 100, 100, and 300 stops, and at the 
dynamometer and adjust the brake as recom- conclusion of the burnishing, in accordance with 
mended by the brake manufacturer. Make 200 the manufacturer's recommendations. ***** 
stops from 40 m.p.h. at a deceleration of 10 fsps, 

with an initial brake temperature on each stop of Issued on March 9, 1988 
not less than 315° F and not more than 385° F. 

Make 200 additional stops from 40 m.p.h. at a Diane K. Steed 

deceleration of 10 f.s.p.s. with an initial brake Administrator 

temperature on each stop of not less than 450° F 53 F.R. 8190 

and not more than 550° F. The brakes shall be March 14, 1988 



PART 571; S105-PRE 106 



PREAMBLE TO AN AMENDMENT TO FEDERAL MOTOR VEHICLE 
SAFETY STANDARD NO. 105 

Hydraulic Brake Systems 

(Docket No. 88-12; Notice 2) 

PIN: 2127-AC50 



ACTION: Final rule. 



SUMMARY: Standard No. 105, Hydraulic Brake Sys- 
tems, requires a vehicle to have one or more brake 
system indicator lamps, to warn its driver about 
certain tjrpes of brake failure and to indicate appli- 
cation of the parking brake. Section S5.3.2 of the 
standard requires that the brake system indicator 
lamps be activated automatically either when the 
ignition switch is turned to the "on" position or to a 
position between "on" and "start," to check whether 
the lamp bulbs are burned out. This notice amends 
the standard to provide that the activation as a 
check of lamp function is not required when a starter 
interlock is in operation. 

DATES: The amendments made by this rule are 
effective June 29, 1989. 

SUPPLEMENTARY INFORMATION: Standard No. 
105, Hydraulic Brake Systems, requires vehicles to 
have one or more brake system indicator lamps, to 
provide a warning to drivers about certain types of 
brake failure and to indicate application of the 
parking brake. Section S5.3.2 of the standard re- 
quires that the brake system indicator lamps be 
activated automatically either when the ignition 
switch is tiu^ned to the "on" position or to a position 
between "on" and "start," to check whether the lamp 
bulbs are burned out. 

On August 18, 1988, NHTSA published in the 
Federal Register (53 FR 31379) a notice of proposed 
rulemaking (NPRM) to amend Standard No. 105 to 
provide that activation as a check of lamp function 
not be provided under any condition in which a 
vehicle cannot be started due to operation of an 
interlock switch. The proposal represented an exten- 
sion of an existing provision. For many years, section 
S5.3.2 has provided that activation as a check of 
lamp function is not required for automatic trans- 
mission vehicles when the transmission shift lever is 
in a forward or reverse drive position. In the NPRM, 
the agency explained the rationale for the existing 
provision as follows: 

. . . (S)ince the purpose of section S5.3.2 of 



Standard No. 105 was to provide an automatic 
check of lamp function each time the vehicle 
was started, it was unnecessary to require the 
check function in situations where the vehicle 
could not be started. Standard No. 102, Trans- 
mission Shift Lever Sequence, Starter Interlock, 
and Transmission Braking Effect, requires for 
vehicles equipped with automatic transmissions 
that the engine starter be inoperative when the 
transmission shift lever is in a forward or re- 
verse drive position. Since vehicles equipped 
with automatic transmissions could not be 
started when the transmission shift lever is in a 
forward or reverse drive position, it was unnec- 
essary to require the check function when the 
transmission shift lever is in either of those 
positions. 53 FR 31380. 

As discussed in the NPRM, Mazda submitted a 
petition for rulemaking requesting an amendment 
of section S5.3.2's provision limiting the conditions 
under which the lamp check function must be pro- 
vided. That company stated that the provision, 
which applied only to automatic transmission vehi- 
cles, should also apply to manual transmission vehi- 
cles which are equipped with a clutch pedal inter- 
lock switch. Mazda stated that this type of interlock 
switch prevents the engine from starting unless the 
clutch pedal is fully depressed, and is analogous to 
the starter interlock required by Standard No. 102 
for automatic transmission vehicles. 

Mazda also asserted that overall cost effectiveness, 
and to a lesser degree, safety, would be enhanced by 
its requested amendment. According to the peti- 
tioner, the amendment would enable manufacturers 
to employ a single wiring harness for the brake 
system indicator lamp circuit for vehicles equipped 
with both manual and automatic transmissions. 
That company stated that it currently designs, pro- 
duces and installs two separate brake system indi- 
cator lamp wiring harnesses, one for manual trans- 
mission vehicles and the other for automatic 
transmission vehicles, which results in unnecessary 
additional costs. Mazda also stated that its re- 



PART 571; S105-PRE 107 



quested amendment would provide an incentive for 
manufacturers to provide clutch pedal starter inter- 
lock switches for vehicles not so currently equipped. 
That company stated that unexpected motion of the 
vehicle during engine activation would be reduced 
as the clutch pedal would be depressed more often in 
a wider variety of vehicles prior to engine activation. 

In the NPRM, NHTSA stated that it agreed with 
the petitioner that, for purposes of section S5.3.2's 
provision limiting the conditions under which the 
lamp check function must be provided, a clutch 
pedal interlock switch for manual transmission ve- 
hicles is analogous to the starter interlock required 
by Standard No. 102 for automatic transmission 
vehicles. Since the purpose of section S5.3.2 of Stan- 
dard No. 105 is to provide an automatic check of 
lamp function each time the vehicle is started, the 
agency tentatively concluded that it was unneces- 
sary to require the check function under any condi- 
tion where a vehicle cannot be started due to opera- 
tion of an interlock switch. The agency therefore 
granted Mazda's petition and proposed to amend 
Standard No. 105 accordingly. NHTSA stated that it 
believed that the proposed amendment would in- 
crease manufacturer flexibility without any adverse 
impact on safety. 

NHTSA received comments on the NPRM from 
Generals Motors, Ford, Chrysler, Volkswagen and 
the Motor Vehicle Manufacturers Association. All of 
them supported the proposal. 

Volkswagen also suggested that Standard No. 105 be 
amended so that the activation of the brake indicator 
lamp when the parking brake is applied satisfies the 
check of lamp requirement. NHTSA notes that the 
amendment suggested by that commenter is not 
within the scope of this particular rulemaking. How- 
ever, the agency has proposed a requirement along 
those lines in its rulemaking to establish an interna- 



tionally harmonized passenger car brake standard. 
See 52 FR 1474, 1483, January 14, 1987. NHTSA will 
continue to handle the issue raised by Volkswagen in 
the context of that rulemaking. 

Based on the reasons discussed above and in the 
NPRM, and on its consideration of the comments, 
NHTSA is adopting the proposed amendment as a 
final rule. Since the amendment imposes no new 
requirements but instead increases manufacturer 
flexibility by relieving a restriction, NHTSA has 
determined that an effective date of 30 days after 
publication in the Federal Register is in the public 
interest. 

In consideration of the foregoing, 49 CFR Part 571 
is amended as follows: 

S5.3.2 of § 571.105 is revised to read as follows: 

S5.3.2 (a) Except as provided in paragraph (b) of 
this section, all indicator lamps shall be activated as 
a check of lamp function either when the ignition 
(start) switch is turned to the "on" (run) position 
when the engine is not running, or when the igni- 
tion (start) switch is in a position between "on" (run) 
and "start" that is designated by the manufacturer 
as a check position. 

(b) The indicator lamps need not be activated 
when a starter interlock is in operation. 

Issued on May 24, 1989 



Jeffrey R. Miller 
Acting Administrator 

54 F.R. 22904 
May 30, 1989 



PART 571; S105-PRE 108 



PREAMBLE TO AN AMENDMENT TO FEDERAL MOTOR 
VEHICLE SAFETY STANDARD NO. 105 

Hydraulic Brake Systems; Air Brakes 

(Docket No. 88-03; Notice 2) 

RIN:2127-AD76 



ACTION: Final rule. 

SUMMARY: Standards No. 105, Hydraulic Brake 
Systems, and No. 121, Air Brake Systems, specify 
procedures for the burnishing or "breaking-in" of a 
vehicle's brakes. Under the two standards' test pro- 
cedures, a vehicle's brakes are burnished prior to 
conducting some of the performance tests for vehicle 
braking. Today's notice amends these standards to 
specify, for all types of vehicles, that automatic brake 
adjusters on vehicles so equipped must remain oper- 
ational during the burnish procedures and subsequent 
brake tests. 

EFFECTIVE DATE: This rule will become effective 
September 1,1991. Optional compliance is permitted 
October 30, 1989 

SUPPLEMENTARY INFORMATION: Standards No. 

105, Hydraulic Brake Systems, and No. 121, Air Brake 
Systems, specify procedures for the burnishing or 
"breaking-in" of a vehicle's brakes. Under the two 
standards' test procedures, a vehicle's brakes are 
burnished prior to conducting some of the performance 
tests for vehicle braking. 

On July 27, 1983, NHTSA published in the Federal 
Register (48 FR 29560) a notice of proposed rulemaking 
(NPRM) to amend the burnish procedures of Standards 
No. 105 and No. 121, as they apply to heavy vehicles. 
One of the proposed changes concerned automatic 
adjusters. The agency noted that Standard No. 105 
specifies for hydraulic-braked vehicles that automatic 
adjusters can be disconnected prior to the burnish 
procedure, but if disconnected, they must remain 
disconnected throughout the brake tests. If the devices 
are not disconnected, a brake adjustment is permitted 
at the end of the burnish and all remaining tests are 
performed with the adjusters connected. On the other 
hand, NHTSA has interpreted Standard No. 121 to 
require for air-braked vehicles that automatic adjusters 
not be disconnected. Today's final rule affirms that 
' interpretation. The July 1983 NPRM proposed to 
specify in both standards, for heavy vehicles, that 



automatic adjusters remain operational during brake 
tests. Under that proposal, vehicles with gross vehicle 
weight ratings (GVWR's) of 10,000 pounds or less 
would continue to have been permitted to be tested 
with automatic adjusters deactivated. 

Some of the commenters on the June 1983 NPRM 
argued that there is no reason to treat vehicles with a 
GVWR in excess of 10,000 pounds differently from 
vehicles with a GVWR of 10,000 pounds or less. These 
commenters stated that if deactivation of automatic 
adjusters is permitted for light vehicles, heavier 
vehicles should be offered the same option. 

On May 23, 1985, NHTSA published in the Federal 
Register {50 FR 21313) a supplemental NPRM (SNPRM) 
concerning a number of the issues raised by com- 
menters in response to the June 1983 notice. With 
respect to automatic adjusters, the agency stated that 
it agreed with the implicit point that the reasons for 
and against permitting the deactivation of automatic 
adjusters apply equally to all vehicles with those 
adjusters, regardless of size. NHTSA announced in 
that notice that rather than address the question of the 
deactivation of automatic brake adjusters in a piecemeal 
fashion, it would instead issue a notice addressing that 
issue for all vehicles. 

On January 14, 1988, NHTSA published in the 
Federal Register (53 FR 934) an NPRM proposing to 
amend Standards No. 105 and No. 121 to specify, for all 
types of vehicles, that automatic brake adjusters 
remain operational during the burnish procedures and 
subsequent brake tests. The proposal allowed for a 
post-burnish brake adjustment in accordance with the 
manufacturer's recommendations as furnished to the 
purchaser (i.e., in the owner's manual). Nine comments 
were received. Of these, seven commenters expressed 
general concurrence with the proposed approach, and 
two objected to it. 

Austin Rover, Volkswagen of America, the Heavy 
Duty Manufacturers Association, and Bendix Heavy 
Vehicle Systems, (commenting on Standard No. 121 
only) expressed support for the proposal. 



PART 571; S105-PRE 109 



General Motors and Chrysler supported the proposal, 
but felt it was inappropriate to require the specific 
brake adjustment information in the owner's manual. 
NHTSA agrees that requiring this technical informa- 
tion in the owner's manual serves little or no useful 
purpose to the consumer. The final rule has been 
revised to specify that after burnishing, the brakes are 
to be adjusted in accordance with the manufacturer's 
recommendation. This will provide manufacturers 
with flexibility to specify recommended adjustments 
in service literature, rather than being required to 
provide that information in the owner's manual 

General Motors, in a comment that is beyond the 
scope of today's rulemaking, also suggested that 
NHTSA issue an SNPRM to clarify the provisions of 
Standards No. 105 and No. 121 that are applicable to 
various types of vehicles. Chrysler recommended that 
the wording of S7.4.1.2 and S7.4.2.2 in Standard No. 
105 be revised to eliminate language addressing the 
lock out of automatic adjusters. NHTSA eliminated 
the language in S7.4.2.2 in a March 14, 1988, final rule. 
Burnish Procedures for Heavy Duty Vehicles, (53 FR 
8190). Today's final rule eliminates the language 
referring to adjuster lock out contained in S7.4.1.2. 

Rockwell International and Bendix Heavy Vehicle 
Systems both recommended that NHTSA allow manual 
adjustment of automatic adjusters during burnish 
procedures under Standard No. 121. Although these 
comments are outside the scope of today's rulemaking, 
NHTSA notes that such adjustments are not precluded 
by the existing regulatory language. The March 1988 
rule provides, with regard to heavy vehicles, that the 
brakes be adjusted in accordance with the man- 
ufacturer's recommendations at specified intervals 
during the burnish procedure, as well as at the end of 
the procedure. Under that rule, automatic adjusters 
are permitted to be manually adjusted at the same 
times as other types of brake adjustments during 
burnish. See, 53 FR 8201-2. That requirement is not 
being changed by today's rule. 

Rockwell also suggested that S5.3 of Standard No. 
121 be revised to allow the readjustment of brakes 
prior to each test sequence. This comment is beyond 
the scope of today's rulemaking. 

Freightliner Corp. indicated that permitting different 
standards for vehicles with automatic, as opposed to 
manual, brake adjusters unfairly penalizes man- 
ufacturers using automatic adjusters. Freightliner 
also provided a comment outside the scope of today's 
rulemaking, relating to brake adjustment intervals 
during brake burnishing. This issue was addressed in 
the March 1988 final rule. 

Ford and Bendix Chassis and Brake Division (a 
supplier of passenger car brake components to Ford) 
submitted comments opposing the proposal to prohibit 
the deactivation of automatic adjusters during bur- 
nishing and testing under Standard No. 105. Ford 



believed that the proposed revisions had no relation to 
improved safety, would provide no benefit to Ford's 
customers, and would require the redesign of brakes ^ 
on various Ford vehicles, resulting in additional costs. I 
Bendix pointed out that its brakes are subject to over- 
adjustment when the automatic adjusters are activated 
during the burnishing and testing, although it is not 
aware of any over-adjustment problems occurring 
during actual use by customers. Bendix also explained 
that redesign of its brakes to include an automatic 
adjuster that would be insensitive to the type of stops 
required by Standard 105 would require a major 
retooling effort and a substantial test and development 
program. Finally, Bendix stated that the increased 
costs of such an effort were not justified, and that the 
proposal should be adopted because it results in no 
benefit to the public, or improvement in safety. 

Since the close of the pubHc comment period on the 
NPRM, NHTSA has been advised by Ford that it is 
changing the designs of its brake systems so that they 
will no longer require deactivation of the automatic 
adjusters during burnishing and testing. As a result. 
Ford has indicated that it no longer objects to the 
revised standard as proposed as long as adequate lead 
time is provided. The final rule provides a lead time 
which NHTSA believes should be adequate for all 
manufacturers, including Ford. 

In the past, problems were sometimes experienced 
with automatic brake adjusters during burnish pro- i 
cedures. For some vehicles, the swelling of linings at ' 
high temperatures made it difficult to complete the 
burnish procedures, an occurence which led the agency 
to permit automatic adjusters to be disconnected 
during testing under Standard No. 105. However, 
newer designs for linings and automatic adjusters 
have essentially eliminated these problems, partic- 
ularly for lighter vehicles. NHTSA is aware of only one 
manufacturer, Ford, which currently specifies that 
the automatic adjusters on any of its vehicles with a 
GVWR of 10,000 pounds or less be deactivated for 
purposes of brake testing. However, as noted above. 
Ford has notified NHTSA of its intention to modify the 
brakes on these models to eliminate the need for 
deactivation. 

One of the purposes behind the various test condi- 
tions and procedures specified in Standards No. 105 
and No. 121 is to test vehicles as they will perform 
when used on the road. Since automatic brake adjusters 
are operational during normal use, specifying that 
they be operational during brake testing helps approx- 
imate real-world conditions and provides a better test 
of real-world performance. 

While it may not be considered normal or typical, the 
potential exists for motorists to drive their vehicles in / 
a manner that could result in the automatic adjusters V 
over-adjusting, an occurence which could lead to 
unexpected brake overheating and thus fade. NHTSA 



PART 571; S105— PRE 110 



believes it is important to amend the rule to reduce the 
possibility of over-adjusting. 

As indicated above, the March 1988 final rule did not 
cover burnish procedures for vehicles with a GVWR of 
10,000 pounds or less. Under today's rule, manual 
adjustment for vehicles with a GVWR of 10,000 
pounds or less is permitted only at the end of the 
burnish procedure. This is consistent with Standard 
No. 105's current requirement for vehicles whose 
automatic adjusters are not deactivated. It is also 
consistent with the agency's proposal for an inter- 
nationally harmonized passenger car brake standard. 
See 52 FR 1474, January 14, 1987. 

NHTSA believes that compliance with today's rule 
will not impose an unreasonable burden upon Ford or 
any other manufacturer. The necessary designs and 
technology needed to overcome any tendency toward 
over-adjusting are available inexpensively and are in 
use by virtually all other manufacturers. NHTSA has 
estimated that the cost of adding the improved adjuster 
design to be no more than $.60 per vehicle. In addition, 
neither Ford nor Bendix submitted any data showing 
that over-adjustment problems during burnish and 
testing still exist with the Ford brake system. NHTSA 
believes that requiring adjusters to be activated during 
testing and burnishing procedures is appropriate and 
promotes the agency's goal of improved motor vehicle 
safety. Finally, as discussed above. Ford has indicated 
its intention to change its existing brake designs 
voluntarily so as to eliminate the need for deactivation 
of the adjusters. Since Ford has been the last man- 
ufacturer to avail itself of the provisions allowing 
lockout of adjusters, there appears to be no reason to 
retain these provisions. 

Today's rule will become effective on September 1, 
1991. Optional compliance will be permitted effective 
30 days after publication in the Federal Register. The 
time period will enable manufacturers to conduct 
compliance testing, as well as make any minor changes 
to their vehicles that might be necessary in order to 
ensure compliance. 
PART 571 -[AMENDED] 

In consideration of the foregoing, 49 CFR Part 571- 
105 is amended as follows: 

S7 is revised to read as follows: 

S7. Test procedures and sequence. Each vehicle shall 
be capable of meeting all the applicable requirements 
of S5. when tested according to the procedures and in 
the sequence set forth below, without replacing any 
brake system part or making any adjustments to the 
brake system other than as permitted in burnish and 
reburnish procedures and in S7.9 and S7.10. (For 
vehicles only having to meet the requirements of 
S5.1.2 and S5.1.3 in section S5.1, the applicable test 
procedures and sequence are S7.1, S7.2, S7.4, S7.9, 



S7.10 and S7.18. However, at the option of the man- 
ufacturer, the following test procedures and sequence 
may be conducted: S7.1, S7.2, S7.3, S7.4, S7.5, S7.6, 
S7.7, S7.8, S7.9, S7.10 and S7.18. The choice of this 
option shall not be construed as adding to the require- 
ments specified in S5.1.2 and S5.1.3.) For vehicles 
manufactured before September 1, 1991, automatic 
adjusters may be locked out, at the option of the 
manufacturer, when the vehicle is prepared for testing. 
If this option is selected, adjusters must remain locked 
out for the entire sequence of tests. For vehicles 
manufactured on or after September 1 , 1991 , automatic 
adjusters must remain activated at all times. A vehicle 
shall be deemed to comply with the stopping distance 
requirements of S5.1 if at least one of the stops at each 
speed and load specified in each of S7.3, S7.5, S7.8, 
S7.9, S7.10, S7.15, or S7.17 (check stops) is made 
within a stopping distance that does not exceed the 
corresponding distance specified in Table II. When the 
transmission selector control is required to be in 
neutral for a deceleration, a stop or snub shall be 
obtained by the following procedures: (1) Exceed the 
test speed by 4 to 8 mph; (2) close the throttle and coast 
in gear to approximately 2 mph above the test speed; (3) 
shift to neutral; and (4) when the test speed is reached, 
apply the service brakes. 

3. S7.4.1.2 is revised to read as follows: 

S7.4.1.2 Brake adjustment— post burnish. After bur- 
nishing, adjust the brakes in accordance with the 
manufacturer's published recommendations. 

4. S7.4.2.2 is revised to read as follows: 

S7. 4.2.2 Brake adjustment— post burnish. After bur- 
nishing, adjust the brakes in accordance with the 
manufacturer's published recommendations. 
Section 571.121 [Amended] 

5. S6 is revised to read as follows: 

S6. Conditions. The requirements of S5 shall be met 
by a vehicle when it is tested according to the conditions 
set forth below, without replacing any brake system 
part or making any adjustments to the brake system 
except as specified. Unless otherwise specified, where 
a range of conditions is specified, the vehicle must be 
capable of meeting the requirements at all points 
within the range. On vehicles equipped with automatic 
brake adjusters, the automatic brake adjusters must 
remain activated at all times. 

Issued on September 26, 1989. 



Jeffrey R. Miller 
Acting Administrator 

54 F.R. 40080 
September 29, 1989 



PART 571; S105-PRE 111-112 



PREAMBLE TO AN AMENDMENT TO FEDERAL MOTOR 

VEHICLE SAFETY STANDARD NO. 105 

Hydraulic Brake Systems 

(Docket No. 91-21; Notice 2) 
RIN:2127-AD34 



ACTION: Final rule. 

SUMMARY: This rule amends Federal Motor 
Vehicle Safety Standard No. 121, Air Brake Sys- 
tems, to require automatic brake adjusters on all 
air-braked vehicles and adjustment indicators on 
air-braked vehicles with external adjustment 
mechanisms. This rule also amends Standard No. 
105, Hydraulic Brake Systems, to require auto- 
matic brake adjusters on vehicles with hydraulic 
brake systems. However, the rule does not require 
adjustment indicators on hydraulically-braked 
vehicles because there do not appear to be signifi- 
cant problems with monitoring automatic brake 
adjusters on such vehicles. These amendments 
should improve the braking performance of 
vehicles by ensuring that their brakes are properly 
adjusted. 

DATES: Effective Dates: The amendments to 
Standard No. 105 become effective October 20, 
1993. 

The amendments to Standard No. 121 become 
effective October 20, 1994. 

SUPPLEMENTARY INFORMATION: 

Background 

General Information 
Proper brake adjustment is critical for maintain- 
ing safe stopping performance. Devices known as 
automatic brake adjusters automatically maintain 
proper brake adjustment, thus eliminating the 
need for frequent inspection and manual adjust- 
ment of the brakes. Automatic brake adjusters 
have been used on passenger cars and light trucks 
since the early 1960s and have been standard 
equipment on all such vehicles sold in recent 
years in the United States. In addition, the vast 
majority of medium and heavy duty vehicles with 
hydraulic brake systems have automatic brake 



adjusters. Automatic brake adjusters were intro- 
duced for use on heavy duty air-braked vehicles 
in the early 1960s and are widely used today. The 
installation rates of automatic brake adjusters by 
manufacturers of heavy duty air-braked vehicles 
range from 30 to 100 percent of their fleets. 

Safety Need and Practicability of Automatic 
Adjustment Devices 

Notwithstanding the importance of proper brake 
adjustment for maintaining safe stopping perform- 
ance, numerous studies have shown that brake 
adjustment is not being maintained on some air- 
braked medium and heavy duty vehicles that are 
not equipped with automatic brake adjusters. (See 
Automatic Slack Adjusters for Heavy Vehicle Air 
Brake Systems, DOT HS 807 724, February 
1991.) When brakes are under-adjusted, stopping 
ability is reduced and the probability of a crash 
is increased. When brakes are over-adjusted, 
maintenance costs and the possibility of a crash 
are increased as a result of excessive lining wear, 
wheel lock, or brake drum cracking. Such 
improper brake adiustment contributes to a 
significant number of crashes, including those in 
which vehicles are unable to stop in time and 
those in which there are "runaways" on steep 
mountain grades. 

As detailed in the notice of proposed rule- 
making (NPRM) for this rulemaking (56 FR 
20396, May 3, 1991), several studies highlight the 
problems associated with improper brake adjust- 
ment, especially on air-braked vehicles. These 
studies include the Office of Technology Assess- 
ment's (OTA's) September 1988 report Gearing 
Up for Safety, NHTSA's March 1987 Heavy 
Truck Safety Study Report to Congress, the 
National Transportation Safety Board's investiga- 
tions of heavy truck crashes, and a Federal High- 
way Administration study. 



PART 571: S105— PRE-113 



Based on the above-mentioned concerns, the 
National Transportation Safety Board rec- 
ommended that NHTSA develop a Federal Motor 
Vehicle Safety Standard requiring all newly 
manufactured commercial vehicles to have equip- 
ment ensuring that brakes are always properly 
adjusted. 

Automatic brake adjusters are now used on 
approximately 60 percent of new medium and 
heavy duty vehicles with air brakes. However, 
one major, and a number of smaller vehicle 
manufacturers, do not provide automatic brake 
adjusters as standard equipment, and many pur- 
chasers do not order them as optional equipment. 

NHTSA believes that automatic brake adjuster 
use has stabilized at about the current 60 percent 
level. NHTSA has conducted a large-scale fleet 
evaluation to assess the performance and reliabil- 
ity of automatic brake adjusters, as compared to 
manual adjusters on heavy commercial vehicles 
with S-cam air brakes. NHTSA collected brake 
adjustment data from several hundred fleet 
vehicles equipped with automatic and manual 
brake adjusters for approximately five years. The 
conclusions regarding the fleet examination are 
detailed in the NPRM. Among the principal 
conclusions were that: 

• Automatic brake adjusters generally maintained 
brake adjustments within the limits specified by 
the vehicle manufacturer. The medium percent- 
age of out-of-adjustment brakes for the fleet 
applications was about four percent. This rep- 
resents a far lower out-of-adjustment rate than 
is commonly found in roadside check studies of 
brake adjustment for manually-adjusted air 
brakes. 

• In the most successful applications, automatic 
brake adjusters consistently exhibited out-of- 
adjustment percentages of less than one per- 
cent. Thus, automatic brake adjusters dem- 
onstrated the potential for very effective 
performance levels. 

• The incidence of brake over-adjustment with 
automatically-adjusted brakes was low. In the 
fleet test, there was no case of an automatic 
brake adjuster over adjusting a brake enough to 
cause brake over-heating, wheel lockup, or 
excessive brake lining wear. 



Automatic Adjusters and Indicators 
on Air Brake Systems 

There are three principal types of air-braked 
systems used in this country: 1) S-cam actuators, 
2) wedge type acmators, and 3) disc brakes. For 
S-cam brakes, which comprise about 95 percent 
of air-brake systems, two major types of auto- 
matic brake adjusters are available. One adjusts 
on the basis of actual shoe-to-drum clearance. The 
other adjusts on the basis of the air chamber push 
rod stroke. All wedge type brakes, which com- 
prise about three percent of the market, have an 
internal automatic adjustment mechanism. As for 
disc brakes which comprise about two percent of 
air-brake systems, some have external self-adjust- 
ing mechanisms, while others have internal 
adjustment features. The external adjustment 
mechanism of an air disc brake system operates 
similarly to those on S-cam brakes. 

Brake adjustment indicators improve brake 
adjustment by increasing the convenience of 
checking brake adjusters and their proper func- 
tioning. Without brake adjustment indicators, 
measuring brake adjustment requires following a 
laborious and time-consuming manual procedure 
in which the push rod length must be measured 
before and during brake application. The proce- 
dure is especially difficult for brake chambers 
located at positions under the vehicle that are dif- 
ficult to reach. Also, a person checking brake 
adjustment must know the specific adjustment 
data for each chamber because some manufactur- 
ers have slightly different stroke lengths for the 
same size chamber. The procedure is also com- 
plicated because the chamber's make and model 
may be difficult to identify when it is covered 
with road dirt and corrosion. 

Several types of brake adjustment indicators are 
currently available. One type involves air brake 
chambers with paint markings on push rods that 
indicate the level of adjustment. However, such 
markings may not be useful in certain applica- 
tions (e.g., with wedge brakes when the push rod 
is enclosed in a sleeve and with S-cam brakes 
having push rods with protective rubber boots). A 
second type of brake adjustment indicator is 
installed by inserting a guide arm and sliding 
stem assembly into a small hole in the air booster 
can. A third method involves attaching a hose 
clamp to the air chamber push rod to mark the 



PART 571; SI 05— PRE- 11 4 



fully adjusted brake position relative to the air 
chamber housing. To check the brake adjustment, 
the space between the air chamber housing and 
hose clamp is compared with a bar gauge. 

Notice of Proposed Rulemaking 

On May 3, 1991. NHTSA published an NPRM 
in which the agency proposed to amend Standard 
No. 121 to require automatic brake adjusters and 
adjustment indicators on vehicles with air brake 
systems. (56 FR 20396) The NPRM also pro- 
posed to amend Standard No. 105 to require auto- 
matic brake adjusters on vehicles with hydraulic 
brake systems. NHTSA decided not to propose 
requiring adjustment indicators on hydraulically- 
braked vehicles because the agency believed that 
there were no significant problems with automatic 
brake adjusters for these vehicles or with check- 
ing the adjustment of such systems. 

Among the issues discussed in the NPRM were 
(1) the need to require automatic brake adjusters 
in passenger cars and other hydraulically braked 
vehicles, (2) specific provisions in the proposed 
language to require automatic brake adjusters on 
passenger cars, (3) the need for automatic brake 
adjusters on air-braked vehicles to correct for 
both under and over-adjustment, (4) the apparent 
absence of a need for automatic adjustment 
indicators for hydraulically braked vehicles, (5) 
visibility requirements for adjustment indicators 
on air-braked vehicles, (6) the necessary leadtime 
for the proposal, and (7) the costs associated with 
the rulemaking. 

Comments to the NPRM and the 
Agency's Response 

NHTSA received about 35 comments in 
response to the NPRM. These were from vehicle 
manufacturers, brake manufacturers, manufactur- 
ers of brake adjusters and adjustment indicators, 
heavy vehicle users, trade associations, and oth- 
ers. The majority of commenters generally agreed 
with the proposal to require brake adjusters on 
both hydraulic and air-braked vehicles and to 
require adjustment indicators on air-braked 
vehicles. In addition, commenters addressed spe- 
cific matters in the proposed regulation, including 
the issues of over-adjustment, visibility require- 
ments, and other provisions in the proposed regu- 
latory text. 

The agency has considered the points raised by 
the commenters in developing the final rule. The 



agency's discussion of the more significant com- 
ments and other relevant information is set forth 
below. The notice first addresses issues about 
automatic adjusters and indicators on vehicles 
equipped with air brakes because the safety prob- 
lem primarily involves, and consequently the 
agency's rulemaking efforts focus on, these 
vehicles. The notice then discusses adjustment 
devices on hydraulically-braked vehicles. 

Air-Braked Vehicles 
1 . General Considerations 

As explained above, the safety problem with 
out-of-adjustment brakes primarily involves air- 
braked vehicles. Accordingly, the agency's rule- 
making efforts have focused on requiring auto- 
matic adjusters and adjustment indicators on such 
vehicles. 

In response to the NPRM's proposal to require 
automatic adjusters on air-braked vehicles, all but 
one commenter addressing this issue supported 
requiring automatic adjusters on air-braked 
vehicles. Those supporting the rulemaking 
included the American Trucking Associations 
(ATA), Truck Trailer Manufacturers Association 
(TTMA), General Motors (GM), Ford, and Advo- 
cates for Highway and Auto Safety (AHAS). 
AHAS stated that the amendments would mitigate 
the extent and severity of fatal and injury produc- 
ing accidents. Only one commenter, Mr. Robert 
Crail, a brake consultant, disputed the need for 
and effectiveness of automatic adjusters on air- 
braked vehicles. Mr. Crail stated that automatic 
adjusters are not accurate enough to be mandated, 
citing raw data about automatic slack adjusters. 

Based on the comments and other available 
information, NHTSA has determined that requir- 
ing automatic adjusters on air-braked vehicles will 
improve the brake performance of these vehicles. 
As the NPRM explained, out-of-adjustment brakes 
pose a significant safety problem that could be 
alleviated by requiring automatic brake adjusters. 
The agency notes that Mr. Crail 's critical com- 
ments were based, in part, on raw data gathered 
from unscreened sources and uncontrolled test 
conditions. Therefore, his conclusions based on 
the data are questionable. While NHTSA 
acknowledges that older brake adjuster designs 
may not perform as well as properly maintained 
manual adjusters, the new generation of currently 
produced automatic adjusters provide superior 
brake adjustment. In addition, even the previous 



PART 571; S105— PRE-115 



generation of automatic brake adjusters are often 
superior to manual adjusters because some owners 
of vehicles with manual adjusters do not take the 
time to properly adjust or otherwise properly 
maintain their brakes. 

2. Proposed Regulatoiy Text 

The NPRM proposed amending Standard No. 
121 to require all vehicles with air brakes to be 
equipped with automatic adjusters. Specifically, 
the NPRM proposed that the standard be amended 
to require these devices on trucks, buses, and 
trailers, as follows: 

Each vehicle shall be equipped with a service 
brake system acting on all wheels. Wear of the 
service brakes shall be compensated for by 
means of a system of automatic adjustment, 
which maintains brake adjustment within the 
manufacturer's recommended adjustment limits. 
The condition of service brake adjustment shall 
be provided by a brake adjustment indicator 
that is discernible when viewed with 20/40 
vision, using an ordinary flashlight with two D- 
cell batteries from a position 8 feet away on 
the adjacent pavement surface. The brake 
adjustment indicator shall be capable of 
displaying the service brake adjustment condi- 
tions of: under-adjustment, over-adjustment, 
and fully adjusted within the manufacturer's 
specified limits. 

Commenters addressed various aspects of the 
proposed regulatory text, including specifying that 
brake adjustment be maintained within the manu- 
facturer's recommended adjustment limits, having 
adjusters correct for under and over adjustment, 
having indicators display the conditions of under, 
over, and full adjustment, and having visibility 
requirements. Along with the comments address- 
ing each of these considerations, the agency's 
response to the comments is presented below. 

a. Brake Adjustment within Manufactnrer' s 
Recommended Adjustment Limits 

As explained above, the NPRM proposed that 
brake adjustment would have to be maintained 
"within the manufacturer's recommended adjust- 
ment limits." The agency had tentatively believed 
that requiring adjustment within the manufactur- 
er's recommended adjustment limits would pro- 
vide a more specific performance requirement. 

Several commenters, including White GMC/ 
Volvo, GM. Ford, Midiand-Grau, and a brake 
indicator manufacturer, criticized the proposal to 



require maintaining brake adjustment within the 
manufacturer's recommended adjustment limits. 
These commenters believed that the proposal was 
unnecessary, ambiguous, and would unreasonably 
burden manufacturers. GM and Ford stated that 
the proposal was potentially ambiguous since 
determining what "maintaining brake adjust- 
ment" means could be interpreted several ways. 
Accordingly, these commenters believed that 
some compliance test would be necessary if the 
agency adopted this provision. White GMC/ 
Volvo, GM, and Ford believed that the proposal 
might be interpreted as requiring the manufacturer 
to be responsible for brake adjustment throughout 
the vehicle's life, even though the manufacturer is 
typically responsible for compliance only until the 
first consumer purchase. In addition, some com- 
menters were concerned that the proposal did not 
specify an objective measure about the proper 
level of adjustment. This consideration led Mid- 
land-Grau to recommend that the standard incor- 
porate the Federal Highway Administration's 
requirements in appendix G to subchapter B of 
Chapter III, Title 49, Code of Federal Regula- 
tions. FHWA, based on input from the Commer- 
cial Vehicle Safety Alliance and brake chambers 
manufacturers, has established a set of brake 
adjustment tables that are published in the North 
American Uniform Vehicle Out-of-Service Cri- 
teria. The States rely on these roadside inspection 
tables to place a vehicle out of service if the 
adjustment limits are exceeded. 

After reviewing the comments and the available 
information, NHTSA has deteiTnined that the final 
rule should not include a reference to maintaining 
adjustment within the manufacturer's rec- 
ommended limits. The agency agrees with com- 
menters that such a provision would not provide 
any significant safety benefits but might cause 
unnecessary complications and confusion. In 
terms of safety benefits, the final rule addresses 
the most important issue by requiring each 
vehicle to be equipped with a service brake sys- 
tem including means for automatic adjustment to 
compensate for wear of the system. The reference 
to the manufacturer's adjustment limits would 
have been superfluous and potentially confusing. 
Nevertheless, as explained below, the agency has 
decided to reference the FHWA's regulations 
about "Vehicle Out-of-Service Criteria." By not 
including reference to maintaining adjustment 
based on the manufacturer's recommendations, 



PART 571; S105— FRE-116 



this amendment is consistent witii the proposed 
requirement about brake adjustment in Standard 
No. 135, Passenger Car Braice Systems. (56 FR 
30528, July 3, 1991). Accordingly, the final rule 
specifies that "Wear of the service brakes shall 
be compensated for by means of a system of 
automatic adjustment."" without reference to a 
manufacturer's adjustment limits. The agency 
notes that there is no objective criteria as to what 
constitutes "maintains adjustment." In addition, 
as a general rule, the agency does not establish 
extended durability testing. The agency believes 
that to require that the adjustment be maintained 
throughout the lifetime of the vehicle is unrealis- 
tic, dependent upon the vehicle's exposure, and 
beyond the scope of NHTSA's authority. 

As for Midland-Grau's recommendation to use 
FHWA's regulations for "Driver Out-of-Service 
Criteria" for brake adjustment, NHTSA has 
decided to reference these provisions in Standard 
No. 121 because they are relevant to in-use heavy 
truck operation regulated by FHWA. Because 
amendments to Standard No. 121 require the use 
of brake adjustment indicators which require the 
display of underadjustment, a reference to adjust- 
ment limits is necessary. Those limits are speci- 
fied in Appendix G to Subchapter B of Chapter 
III, 49 CFR Parts 200 to 399. 

b. Brake Over-adjustment and Under-adjust- 
ment 

The NPRM tentatively concluded that auto- 
matic brake adjusters should have the capability 
of correcting for both under and over-adjustment. 
The NPRM also proposed that a brake adjustment 
indicator be capable of displaying the brake 
adjustment conditions of under-adjustment, over- 
adjustment, and fully adjusted. The notice 
requested comments about whether these require- 
ments were feasible and whether they should be 
specified in the regulatory text. 

Twelve commenters, primarily heavy brake and 
vehicle manufacturers, opposed requiring brake 
adjusters to correct for over-adjustment. These 
commenters also opposed requiring the brake 
adjustment indicators to identify the over-adjusted 
and fully adjusted conditions. User groups, such 
as the Owner-Operator Independent Drivers 
Association supported these proposals. Navistar, 
Haldex, Bendix, Midland-Grau, Rockwell, Ford, 
the MVMA, Chrysler, Eaton, and the ATA 
believed that requiring the device to control for 
over-adjustment and having the adjustment indica- 



tor identify this condition were unnecessary and 
impracticable. MVMA stated that the incidence of 
over-adjustment is very infrequent and poses a 
minimal risk to safety. In addition, several manu- 
facturers explained that the condition of over- 
adjustment can be ascertained by excessive wear, 
abuse of the equipment, and in extreme cases, 
smoke. The commenters also stated that the pro- 
posal was impracticable because there was no 
current technology that reliably indicates the over- 
adjusted condition. After reviewing the comments 
and available information, NHTSA concludes that 
requiring brake adjusters to correct for over- 
adjustment and having adjustment indicators show 
the over-adjusted and fully-adjusted conditions are 
unnecessary for safety and would be impractica- 
ble. In terms of the safety need, the fleet evalua- 
tion cited in the NPRM concluded that the 
incidence of brake over-adjustment was extremely 
low. NHTSA further notes that potential problems 
associated with over-adjustment will not be 
significant. The driver typically will be aware of 
over-adjustment because the brake system will 
drag and may begin to smoke. In terms of prac- 
ticability, the NPRM's tentative determination 
about the availability of automatic brake adjusters 
to correct for over-adjustment appears to be 
inconsistent with the current state of brake tech- 
nology. The agency now agrees with the com- 
ments that regulating over-adjustment would be 
impracticable given that such devices are not 
readily available. Based on the above, the final 
rule does not require brake adjusters to correct for 
over-adjustment and does not require the adjust- 
ment indicators to show the over-adjusted and 
fully-adjusted conditions. 

As for the condition of under-adjustment, most 
commenters, including Rockwell, MVMA, Ford, 
and GM believed that the agency should intro- 
duce requirements to prevent this brake condition. 
MVMA stated that the primary motivation and 
safety benefit underlying automatic brake adjust- 
ers is to minimize the incidence of under-adjust- 
ment. 

After reviewing the comments and the available 
information, NHTSA has decided to adopt provi- 
sions requiring brake adjusters to correct for the 
condition of service brake under-adjustment and 
have a device that indicates the under-adjusted 
condition. The agency agrees with the com- 
menters that under adjustment poses a significant 
risk to safety. In addition, NHTSA believes that 



PART 571; S105— PRE-117 



this requirement is practicable since there cur- 
rently are several devices that are capable of 
indicating the under-adjusted condition. Accord- 
ingly, Sections 5.1.8 and S5.2.2 are amended to 
read, in relevant part, "(b) Brake indicator. .. the 
condition of service brake under-adjustment shall 
be provided by a brake adjustment indicator ... 

c. Visibility Requirements for Brake Adjust- 
ers 

The NPRM proposed that the brake adjustment 
indicator be discernible when viewed with 20/40 
vision, using an ordinary flashlight with two D- 
cell batteries from a position at least eight feet 
away on the adjacent pavement surface. The 
agency believed that these visibility requirements 
would allow a person to check brake adjustment 
without having to crawl under the vehicle. 

Commenters offered various views about the 
proposed visibility requirements. Manufacturers of 
aftermarket add-on indicators favored the pro- 
posal, while vehicle manufacturers and custom 
builders objected. Users of brake equipment 
offered mixed views. 

Several commenters, including Mack, Navistar. 
GM, the National Truck Equipment Association 
(NTEA), Haldex, the Truck Trailer Manufacturers 
Association (TTMA), and Flxible stated that the 
proposed visibility requirements were impractica- 
ble, especially for those vehicle configurations in 
which the line of sight to the air brake chambers 
is obscured. In many vehicles, including buses, 
beverage haulers, walk-in vans, ambulances, low- 
bed trucks, utility trailers, and tank-trucks, the 
brake adjustment indicator may only be inspected 
by crawling under a vehicle. Mack explained that 
many vehicle configurations make it difficult or 
impossible to view the chamber from eight feet 
away because brake chambers are frequently 
located in positions that are obscured by tires, 
hoods, and other vehicle components. In addition, 
Rockwell stated that in-service environmental fac- 
tors such as mud, salt, and grease would prevent 
the reading of the adjustment indicator unless the 
chamber were wiped off. 

These practicability concerns with the proposed 
visibility requirements led commenters to rec- 
ommend modifying the proposal. GM rec- 
ommended a simplified requirement in which the 
indicator would have to be discernible when 
viewed with 20/40 vision from outside or the 
underside of the vehicle. Ford suggested that the 



visibility requirement allow inspection from either 
side of or under the vehicle. 

After reviewing the comments, NHTSA has 
decided not to adopt the detailed visibility pro- 
posal because the requirement would raise signifi- 
cant practicability problems. The agency notes 
that the proposed eight foot requirement would 
necessitate extensive redesign of certain vehicle 
configurations such as drop floor and moving 
vans. In addition, the proposed visibility require- 
ment would be impracticable for evaluating brake 
adjusters that have been covered by road contami- 
nants such as dirt, grime, and snow. NHTSA 
believes that by not adopting the eight foot view- 
ing requirement, the standard will encourage 
closer hands-on inspection of the equipment. 
Based on the above considerations, the agency 
has decided not to require that the adjustment 
indicator be readable at a distance of eight feet. 
The visibility provision now states that "the 
condition of service brake under-adjustment shall 
be provided by a brake adjustment indicator that 
is discernible when viewed with 20/40 vision 
from a location adjacent to or underneath the 
vehicle." 

d. Vehicle Type 

The NPRM proposed that all air-braked 
vehicles be equipped with an adjustment indica- 
tor, regardless of brake system type. The NPRM 
explained that there were three principal types of 
air brake systems: S cam brakes which account 
for 95 percent of the brake market; wedge type 
brakes, three percent of the market; and disc 
brakes, two percent of the market. While S cam 
brakes have external adjustment mechanisms, 
wedge brakes and some disc brakes have internal 
mechanisms. 

Several commenters, including Volvo GM 
Heavy Truck, Navistar, GM, Bendix, Rockwell, 
and MVMA, stated that adjustment indicators are 
only practicable with external adjustment designs 
such as S cam brakes with exposed push rods. 
MVMA stated that there was little if any need to 
require adjustment indicators on internally 
adjusted brakes. Like hydraulic brakes, air-brake 
systems with internal adjustment designs would 
have to be significantly redesigned to incorporate 
an adjustment indicator. Rockwell believed that 
the nominal benefits from having wedge brakes 
and internally adjusted disc brakes equipped with 
indicators did not wanant the significant costs 
that would be needed to redesign these systems. 



PART 571; S105— PRE-118 



Bendix and Lear Siegler explained that some 
external actuators are equipped with a protective 
boot or a scraper seal. 

After reviewing the comments and the available 
information, NHTSA has determined that 
although all air brakes should have a system of 
automatic adjustment, it is not necessary to 
require adjustment indicators on internally 
adjusted brakes. The agency is not aware of any 
significant adjustment problems with internally 
adjusted brakes. In addition, such a requirement 
for these designs would not be practicable given 
the significant feasibility concerns and redesign 
costs to require an adjustment indicator on 
internally adjusted brake systems. The agency 
notes that S cam brakes, except the approximately 
one percent that have protective pushrod boots, 
have exposed air chamber pushrods which easily 
can be marked to indicate brake adjustment. 

S cam brakes whose pushrods are covered 
by protective boots cannot be simply marked, 
since the markings would not be visible to outside 
inspection. The NPRM did not propose to exempt 
booted systems from having to have adjustment 
indicators, describing two designs that have the 
potential to indicate adjustment of such systems. 
In commenting to the docket, Lear Siegler, a 
major air chamber manufacturer, stated that air 
brake actuators equipped with protective boots 
should be exempt from adjustment indication in 
its cuiTcnt technological fonn. Bendix commented 
that brake actuators with pushrod boots or scraper 
seals should be exempted. 

After a review of the comments to the docket 
and other infonnation on this issue, the agency 
has decided not to require adjustment indicators 
on service brake systems that have pushrod boots. 
Systems having scraper seals and exposed 
pushrods will be required to have adjustment 
indicators, since the pushrods can be easily 
marked and inspected. Brake actuators with 
pushrod boots are made to provide performance 
and reliability under severe operating conditions, 
such as corrosive or hazardous material handling 
and refuse collection and disposal. The heavy- 
duty, durable adjustment indicators, adequately 
integrated into the actuator system, that would be 
necessary to withstand these severe operating 
environments, would cost substantially more than 
indicators on exposed pushrods. Brake systems 
with pushrod boots account for perhaps one per- 
cent of the brake actuator market, as previously 



noted. These systems are being required to have 
automatic brake adjusters. Further, many booted 
systems are used with rolling diaphragm brake 
chambers (roto chambers) that have longer strokes 
than conventional chambers and thus provide a 
greater operating range for automatic slack adjust- 
ers and a longer period of use before the 
underadjustment condition is reached. While the 
agency is not requiring brake systems with booted 
pushrods to have adjustment indicators, it would 
revisit this issue if the number of these systems 
increase substantially in the future. Thus, the 
agency is only requiring externally adjusted 
brakes with exposed pushrods to be equipped 
with adjustment indicators. The agency estimates 
that about 94 percent of air brakes will be 
equipped with indicators. 

3. Miscellaneous Concerns 

Several commenters, including brake indicator 
manufacturers and user groups, requested that the 
agency require air-braked vehicles that are cur- 
rently in use to be retrofitted with automatic 
adjusters and adjustment indicators. NHTSA notes 
that the National Traffic and Motor Vehicle 
Safety Act of 1966 (15 U.S.C. 1381) authorizes 
the agency to promulgate safety standards for new 
vehicles only. The Act does not provide the 
agency with out authority to require the retro- 
fitting of in-use vehicles. Therefore, the agency 
cannot require in-use vehicles to be equipped with 
automatic brake adjusters or adjustment indica- 
tors. 

Flxible commented that it should be allowed 
the option of using manual slack adjusters during 
its certification testing. NHTSA notes that Flxible 
can do whatever it wants in its compliance test- 
ing, if it can establish, should it become necessary 
to do so, that use of its test procedure constitutes 
due care. Nevertheless, NHTSA believes that 
Flxible may have difficulty establishing due care 
if it uses manual adjusters during its certification 
testing, because an earlier rulemaking prohibited 
the disconnecting of automatic adjusters during 
agency compliance testing. (54 FR 40080, 
September 28, 1989). That notice explained that 
an important purpose behind the test conditions 
and procedures is to test vehicles as they will per- 
form when used on the road. Since automatic 
brake adjusters are operational during normal use, 
specifying that they be operational during agency 
compliance testing helps approximate real-world 



PART 571; S105— PRE-119 



conditions and provides a better test of real-world 
performance. 

Advocates for Highway and Auto Safety asked 
whether dollies are required to be equipped with 
automatic adjusters and adjustment indicators 
under the proposals. The requirement for auto- 
matic adjusters and adjustment indicators is 
applicable to dollies since section 571.3 defines a 
"trailer converter dolly" as "a trailer chassis 
equipped with one or more axles, a lower half of 
a fifth wheel and a drawbar." Since trailer chassis 
are trailers and trailers are subject to the require- 
ment, trailer converter dollies also are subject to 
the requirement. 

The ATA requested an exclusion from the 
automatic adjuster requirements for vehicles 
involved in "permit" operations such as 
transporting hazardous waste and explosives. 
While NHTSA has the authority to set standards 
based on vehicle type, it does not typically have 
the authority to set standards based on end use 
(aside from school buses). Even if it had such 
authority, vehicle manufacturers could not predict, 
in many instances, which vehicles were ultimately 
going to be used for permit operations and thus 
could not identify which vehicles were excluded. 
Many vehicles used in permit operations are 
standard trucks and trailers with no special fea- 
tures. If the agency were to attempt to exclude the 
permit operation vehicles by excluding whole 
vehicle types, the exclusion would be overbroad. 
The agency notes that a variety of vehicle types 
are used for these permit operations, and if 
NHTSA were to exclude all of these types, it 
would be excluding many vehicles not used for 
permit operations. In addition, the professed rea- 
son to exclude vehicles in permit operations (i.e., 
the presumed frequency of manual brake adjust- 
ments) can be accomplished with brakes equipped 
with automatic adjusters. Some truckers involved 
in dangerous activities adjust their brakes every 
day instead of relying on their automatic adjust- 
ers, because automatic adjusters are equipped with 
external adjusting mechanisms similar to the man- 
ual adjusters. Therefore, if a permit hauler desires 
to adjust its brakes manually, it can do so. Based 
on the above, the agency believes that heavy 
haulers involved in permit operations should be 
required to comply with the automatic adjustment 
requirements. 

International Transquip recommended a salt 
spray test and a stroke cycle test for accuracy, 



performance, and readability. NHTSA notes that 
these tests were not proposed in the NPRM and 
does not believe they are necessary at this time. 
The agency believes that a safety need for these 
additional requirements could not be established. 
In addition, the existing SAE Recommended Prac- 
tice on automatic adjusters already requires 
environmental chamber tests along with cycle 
testing. If additional information indicated that 
these tests would provide significant safety bene- 
fits at reasonable costs, the agency would con- 
sider proposing them. 

MGM Brakes commented that the SAE Truck 
and Bus Brake Actuator Sub-Committee has writ- 
ten and approved a recommended practice for 
cam or disc brake actuators. However, the SAE 
has withheld this document from publication 
because its policy is to not publish any rec- 
ommended practice that will require another 
manufacturer to infringe a patent. Apparently, one 
air brake actuator manufacturer was recently 
issued a patent on a stroke indicator marking sys- 
tem. Notwithstanding the SAE's concern about 
patent infringement, NHTSA notes that this rule 
specifies a general performance standard. There- 
fore, the agency does not anticipate that restric- 
tions caused by patents will be a problem because 
there are many different indicator designs and air 
chamber push rods may be marked in many ways. 

Hydraulically-Braked Systems 

1. Brake Adjusters 

The NPRM discussed the need for automatic 
brake adjusters on hydraulically-braked vehicles, 
including passenger cars. The notice explained 
that all new passenger cars have been manufac- 
tured with automatic adjusters for several years. 
The agency stated that such a requirement would 
be consistent with the agency's proposal in Stand- 
ard No. 135 about international brake harmoni- 
zation (52 FR 1474, January 14, 1987, 56 PR 
30528, July 3, 1991). The proposal requested 
comments on whether passenger cars should be 
covered by this amendment to Standard No. 105. 
The proposal also requested comment about 
whether other hydraulically-braked vehicles 
should be required to have automatic brake 
adjusters. 

No commenter expressly supported equipping 
passenger cars and other hydraulic braked 
vehicles with automatic brake adjusters. However, 
several commenters, including General Motors 



PART 571; SI 05— PRE- 120 



and the Motor Vehicle Manufacturers Association 
(MVMA), imphcitly supported this requirement 
by commenting that an immediate effective date 
for such vehicles was feasible, provided that the 
requirements did not require the development of 
new designs. Chrysler and Toyota questioned the 
need for such a requirement, claiming that 
hydraulically-braked vehicles are already 
equipped with such devices. 

In addition. Ford and GM commented that, in 
the interests of international brake harmonization, 
the requirements about brake adjusters in Stand- 
ard No. 105 and 135 should be identical. This 
consideration led Ford to state that the proposal 
in Standard No. 10105 about automatic correction 
for over-adjustment was not needed. 

After reviewing these comments, NHTSA has 
determined that Standard No. 105 should be 
amended to require automatic brake adjusters. 
Because vehicles subject to Standard No. 105 
typically are equipped with these devices, the 
agency does not anticipate that the requirement 
would pose a burden on manufacturers. In addi- 
tion, amending Standard No. 105 to require these 
devices will result in consistency between that 
Standard and Standard No. 135. The agency notes 
that such consistency is important because under 
the Standard No. 135 proposal, a manufacturer 
could comply with either standard during the five- 
year phase-in period for Standard No. 135. 

2. Adjustment Indicators 

The NPRM stated that even though brake 
adjusters would be required on hydraulically- 
braked vehicles, automatic adjustment indicators 
would not be required on these vehicles. The 
notice explained that the agency believed that 
there were no significant problems with automatic 
brake adjusters for hydraulically-braked vehicles 
or with checking the adjustment of the brakes on 
such vehicles. Nevertheless, the agency requested 
comments about whether adjustment indicators 
should be required on hydraulically-braked 
vehicles. 

Chrysler believed that allowing continued vol- 
untary compliance would be more appropriate 
than mandating installation tlirough rulemaking. 
GM and MVMA stated that indicators should not 
be required on hydraulic brakes because no safety 
need for such a requirement has been dem- 
onstrated. 

NHTSA continues to believe that there is no 
significant safety problem with automatic adjust- 



ers for hydraulically-braked vehicles or with 
checking the adjustment of such vehicles. Accord- 
ingly, the agency has decided not to require 
adjustment indicators on hydraulically-braked 
vehicles. 

Effective Date 

The NPRM proposed that the amendments 
become effective two years after promulgation of 
the final rule. The agency proposed the same 
leadtime for both air-braked and hydraulically- 
braked vehicles. 

With respect to automatic brake adjusters on 
air-braked vehicles, the notice explained that most 
truck and bus manufacturers already offer auto- 
matic brake adjusters as standard equipment. The 
agency acknowledged that most truck trailer 
manufacturers do not offer automatic brake 
adjusters as standard equipment; about 30 percent 
of all new trailers are presently ordered with auto- 
matic brake adjusters. In addition, the agency esti- 
mated that about 60 percent of all new medium 
and heavy trucks, buses, and trailers already have 
automatic brake adjusters. NHTSA believed that a 
switch from manual to automatic brake adjusters 
would not require major redesigns of more than 
a few, if any, vehicles because automatic brake 
adjusters are already available for most vehicles 
with manual adjusters and the overall brake sys- 
tem is about the same size, with or without auto- 
matic adjusters. The NPRM further stated that 
manufacturers of automatic brake adjusters could 
easily supply enough adjusters to equip all new 
air-braked trucks, buses, and trailers within two 
years. 

The NPRM also stated that two years was 
sufficient leadtime for the brake adjustment 
indicator requirement, noting that two major air 
brake manufacturers, with over 75 percent of the 
market, already mark their push rods with a visual 
indicator for under-adjustment. The notice stated 
that other manufacturers should be able to 
develop a brake adjustment indicator within two 
years. The agency requested comments on the 
adequacy of the leadtime generally and specifi- 
cally for any particular types of vehicles or brake 
systems which would require extensive redesign. 
The notice explained that the agency would con- 
sider providing longer leadtime for vehicles or 
brake systems which needed additional leadtime. 

Thirteen commenters addressed the proposed 
leadtime for requiring brake adjusters and adjust- 



PART 571; S105— PRE-I21 



merit indicators on air-braked vehicles. The Inter- 
national Brotherhood of Teamsters and a brake 
consultant believed that a leadtime of one year or 
less was appropriate, claiming that the equipment 
is already available. Haldex stated that a one year 
lead time would be possible provided that the 
issue of adjustment indicators was separated. Sev- 
eral commenters, including Ford, the National 
School Transportation Association (NSTA), the 
American Petroleum Institute, the Owner-Operator 
Independent Drivers Association, TTMA, GM, 
and MVMA believed that the proposed two year 
leadtime was appropriate for requirements similar 
to those being adopted in this final rule. Chrysler 
believed that leadtime of three years would be 
necessary for some manufacturers to develop 
automatic adjusters and indicators. 

NHTSA continues to believe that a two year 
leadtime will provide manufacturers adequate 
time to equip air-braked vehicles with brake 
adjusters and adjustment indicators. The agency 
notes that the final rule omits several provisions 
that would have raised significant practicability 
concerns for some vehicle and brake designs. 
NHTSA further notes that although some manu- 
facturers already comply or could quickly bring 
their vehicles into compliance with the require- 
ments, a significant number of small trailer manu- 
facturers would have difficulty complying with 
the amendments unless a two year leadtime is 
provided. 

As for hydraulically-braked vehicles, the notice 
also proposed that the amendment become effec- 
tive two years after publication of the final rule. 
The NPRM requested comment on whether a 
shorter leadtime for hydraulically-braked vehicles 
was appropriate since these vehicles are typically 
produced with automatic brake adjusters. 

GM and MVMA stated that an immediate 
effective date for hydraulically-braked vehicles 
would be acceptable, provided that the amend- 
ments did not require the development of new 
designs. Ford stated that the two year time period 
was more than adequate. No commenter requested 
a leadtime for hydraulically-braked vehicles 
longer than two years. 

Based on the comments and available informa- 
tion, NHTSA has determined that a one year lead- 
time is appropriate for requiring automatic adjust- 
ers on hydraulically-braked vehicles. Those com- 
menters that addressed the issue indicated that an 
immediate effective date would be acceptable. No 



commenter stated that an effective date longer 
than one year was necessary or that a one year 
leadtime would pose an unreasonable burden. 
Based on its review of hydraulically-braked 
vehicles, NHTSA believes that all such passenger 
cars and light trucks are equipped with an auto- 
matic adjuster. As for hydraulically-braked 
medium and heavy duty vehicles, the agency 
notes that these vehicles are typically manufac- 
tured by specialty manufacturers that purchase the 
axle sets and brake components from major 
manufacturers. The agency believes that the major 
manufacturers or trade groups representing the 
specialty manufacturers would have expressed 
their concern if a shorter leadtime had posed a 
hardship. 

This final rule does not have any retroactive 
effect. Under section 103(d) of the National Traf- 
fic and Motor Vehicle Safety Act (15 U.S.C. 
1392(d)), whenever a Federal motor vehicle safety 
standard is in effect, a state may not adopt or 
maintain a safety standard applicable to the same 
aspect of performance which is not identical to 
the Federal standard. Section 105 of the Act (15 
U.S.C. 1394) sets forth a procedure for judicial 
review of final rules establishing, amending or 
revoking Federal motor vehicle safety standards. 
That section does not require submission of a 
petition for reconsideration or other administrative 
proceedings before parties may file suit in court. 

Part 571— [Amended] 

In consideration of the foregoing, 49 CFR Part 
571 is amended as follows: 

1. The authority citation for Part 571 continues 
to read as follows: 

Authority: 15 U.S.C. 1392, 1401, 1403, 1407; 
delegation of authority at 49 CFR 1.50. 

§571.105 [Amended] 

2. S5.1 of §571.105 is amended by adding the 
following after the current heading: 

Each vehicle shall be equipped with a service 
brake system acting on all wheels. Wear of the 
service brake shall be compensated for by means 

of a system of automatic adjustment. 

***** 

§571.121 [Amended] 

3. S5.1.8 of §571.121 is revised to read as fol- 
lows: 



PART 571; S105— PRE-122 



S5.1.8 Brake distribution and automatic adjust- 
ment. Each vehicle shall be equipped with a serv- 
ice brake system acting on all wheels. 

(a) Brake adjuster. Wear of the service brakes 
shall be compensated for by means of a system 
of automatic adjustment. The readjustment limits 
shall be in accordance with those specified in 
Appendix G to Subchapter B of Chapter III - 
"Minimum Periodic Inspection Standards," 49 
CFR Parts 200 to 399. 

(b) Brake indicator. For each brake equipped 
with an external automatic adjustment mechanism 
and having an exposed pushrod, the condition of 
service brake under-adjustment shall be displayed 
by a brake adjustment indicator that is discernible 
when viewed with 20/40 vision from a location 
adjacent to or underneath the vehicle. 

4. S5.2.2 of §571.121 is revised to read as fol- 
lows: 

S5.2.2 Brake distribution and automatic adjust- 
ment. Each vehicle shall be equipped with a serv- 
ice brake system acting on all wheels. 



(a) Brake Adjuster. Wear of the service brakes 
shall be compensated for by means of a system 
of automatic adjustment. The readjustment limits 
shall be in accordance with those specified in 
Appendix G to Subchapter B of Chapter III — 
"Minimum Periodic Inspection Standards," 49 
CFR Parts 200 to 399. 

(b) Brake Indicator. For each brake equipped 
with an external automatic adjustment mechanism 
and having an exposed pushrod, the condition of 
service brake under-adjustment shall be displayed 
by a brake adjustment indicator in a manner that 
is discernible when viewed with 20/40 vision 
from a location adjacent to or underneath the 
vehicle. 

Issued on October 14, 1992. 



Marion C. Blakey 
Administrator 



57 F.R. 47793 
October 20, 1992 



PART 571; S105— PRE-123 



MOTOR VEHICLE SAFETY STANDARD NO. 105 
Hydraulic Brake Systems 



51. Scope. This standard specifies requirements 
for hydraulic service brake and associated parking 
brake systems. 

52. Purpose. The purpose of this standard is to 
insure safe braking perfomiance under normal and 
emergency conditions. 

53. Application. This standard applies to pas- 
senger cars, multipurpose passenger vehilces, 
trucks, and buses with hydraulic service brake sys- 
tems. 

54. Definitions. Antilock system means a portion 
of a service brake system that automatically con- 
trols the degree of rotational wheel slip at one or 
more road wheels of the vehicle during braking. 

Backup system means a portion of a service 
brake system, such as a pump, that supplies 
energy in the event of a primary brake power 
source failure. 

Brake power assist unit means a device 
installed in a hydraulic brake system that reduces 
the operator effort required to actuate the system, 
and that if inoperative does not prevent the opera- 
tor from braking the vehicle by a continued 
application of muscular force on the service brake 
control. 

Brake power unit means a device installed in a 
brake system that provides the energy required to 
actuate the brakes, either directly or indirectly 
therugh an auxiliary device, with the operator 
action consisting only of modulating the energy 
application level. 

Hydraulic brake system means a system that 
uses hydraulic fluid as a medium for transitting 
force from a service brake control to the service 
brake, and that may incorporate a brake power 
assist unit, or a brake power unit. 

Initial brake temperature means the average 
temperature of the service brakes on the hottest 
axle of the vehicle 0.2 miles before any brake 
application. 

Lightly loaded vehicle weight means: 



(a) for vehicles with a GVWR of 10,000 
pounds or less, unloaded vehicle weight plus 500 
pounds (including driver and instrumentation); 

(b) for vehicles with a GVWR greater than 
10,000 pounds, unloaded vehicle weight plus 500 
pounds (including driver and instrumentation). 

Parking mechanism means a component or sub- 
system of the- drive train that locks the drive 
train when the transmission control is placed in a 
parking or other gear position and the ignition 
key is removed. 

Pressure component means a brake system 
component that contains the brake system fluid 
and controls or senses the fluid pressure. 

Skid number means the frictional resistance of 
a pavement measured in accordance with Amer- 
ican Society for Testing and laterials (ASTM) 
Method E-274-70 (as revised July, 1974) at 40 
mph, omitting water delivery as specified in para- 
graphs 7. 1 and 7.2 of that method. 

Snub means the braking deceleration of a 
vehicle from a higher reference speed to a lover 
reference speed that is greater than zero. 

Spike stop means a stop resulting from the 
application of 200 pounds of force on the service 
brake control in 0.08 second. 

Split senice brake system means a brake sys- 
tem consisting of two or more subsystems 
actuated by a single control designed so that a 
leakage-type failure of a pressure component in a 
single subsystem (except structural failure of a 
housing that is common to two or more sub-sys- 
tems) shall not impair the operation of any other 
subsystem. 

Stopping distance means the distance traveled 
by a vehicle from the point of application of force 
to the brake control to the point at which the 
vehicle reaches a full stop. 

Variable proportioning brake system means a 
system that automatically adjusts the braking 
force at the axles to compensate for vehicle static 



PART 571; S 105-1 



axle loading and/or dynamic weight transfer 
between axles during deceleration. 

S5. Requirements. 

S5.1 Service brake systems. [Each vehicle 
shall be equipped with a service brake system act- 
ing on all wheels. Wear of the service brake shall 
be compensated for by means of a system of auto- 
matic adjustment. (57 F.R. 47793 — October 20, 
1992. Effective: October 20, 1993)] 

S5.1.1 Stopping distance. The service brakes 
shall be capable of stopping each vehicle, other 
than a vehicle which both has a GVWR of not less 
than 8,000 pounds and not greater than 10,000 
pounds and is not a school bus, in four effective- 
ness tests within the distances and from thespeeds 
specified in S5. 1.1.1, S5.1.1.2. S5.1.1.3, and 
S5. 1.1.4. The service brakes shall be capable of 
stopping each vehicle which both has a GVWR of 
not less than 8,000 pounds and not greater than 
10,000 pounds and is not a school bus, in three 
effectiveness tests within the distances and from 
the speeds specified in S5. 1.1.1, S5. 1.1.2, and 
S5.1.1.4. 

S.I .1.1 In the first (prebumished) effectiveness 
test, the vehicle shall be capable of stopping from 
30 mph and 60 mph within the corresponding dis- 
tances specified in Column I of Table II. 

S5.1.1.2 In the second effectiveness test, the 
vehicle shall be capable of stopping from 30 and 
60 mph within the corresponding distances speci- 



fied in Column II of Table II. If the speed attain- 
able in 2 miles is not less than 84 mph, a pas- 
senger car or other vehicle with a GVWR of 
10,000 pounds or less shall also be capable of 
stopping from 80 mph within the corresponding 
distances specified in Column II of Table II. 

55.1.1.3 In the third effectiveness test the vehicle 
shall be capable of stopping at lightly loaded 
vehicle weight from 60 mph within the cor- 
responding distance specified in Column III of 
Table II. 

55.1.1.4 In the fourth effectiveness test, a vehicle 
with a GVWR of 10,000 pounds or less shall be 
capable of stopping from 30 and 60 mph within 
the corresponding distances specified in Column I 
of 7 Table II. If the speed attainable in 2 miles is 
not less than 84 mph, a passenger-car lor other 
vehicle with a GVWR of 10,000 lbs. or less shall 
also be capable of stopping from 80 mph within 
the corresponding distance specified in Column I 
of Table II. 

If the speed attainable in 2 miles is not less 
than 99 mph, a passenger car shall, in addition, 
be capable of stopping from the applicable speed 
indicated below, within the corresponding dis- 
tance specified in Column I of Table II. 



Speed attainable in 2 miles (mph) 



Required to stop 
from (mph) 



Not less than 99 but less than 104 
104 or more 



95 
100 



TABLE I— BRAKE TEST PROCEDURE SEQUENCE AND REQUIREMENTS 



No. 



Sequence 



Test Load 



Light 



GVWR 



Test Procedure 



Require- 
ments 



1. Instrumentation check 

2. First (prebumish) effectiveness test 

3. Burnish procedure 

4. Second effectiveness 

5. First rebumish 

6. Parking brake 

7. Third effectiveness (lightly loaded vehicle) 

8. Partial failure 

9. Inoperative brake power and power assist units 

10. First fade and recovery 

11. Second rebumish 

12. Second fade and recovery 

13. Third rebumish 

14. Fourth effectiveness 

15. Water recovery 

16. Spike stops 

17. Final inspection 

18. Moving barrier test 



S7.3 


S5.1.1.i 


S7.4 


— 


S7.5 


S5.1.1.2 


S7.6 


— 


S7.7 


S5.2 


S7.8 


S5.1.1.3 


S7.9 


S5.1.2 


S7.10 


S5.1.3 


S7.ll 


S5.1.4 


S7.12 


— 


S7.13 


S5.1.4 


S7.14 


— 


S7.15 


S5.1.1.4 


S7.16 


S5.1.5 


S7.17 


S5.1.6 


S7.18 


S5.6 


S7.19 


S5.2.2.3 



(Rev. 10/20/92) 



PART 571; S 105-2 



S5.1.2 Partial failure. 

55.1.2.1 In vehicles manufactured with a split 
service brake system, in the event of a rupture or 
leakage type of failure in a single subsystem, other 
than a structural failure of a housing that is com- 
mon to two or more subsystems, the remaining 
portion(s) of the service brake system shall con- 
tinue to operate and shall be capable of stopping 
a vehicle from 60 mph within the corresponding 
distance specified in Column IV of Table II. 

55.1.2.2 In vehicles not manufactured with a split 
service brake system, in the event of any one rup- 
ture or leakage type of failure in any component 
of the service brake system the vehicle shall by 
operation of the service brake control, be capable 
of stopping 10 times consecutively from 60 mph 
within the corresponding distance specified in 
Column IV of Table II. 

[S5.1.3 Inoperative brake power assist unit or 
brake power unit. A vehicle equipped with one 
or more brake power assist units shall meet the 
requirements of either S5. 1.3.1, S5. 1.3.2, or 
S5. 1.3.4 (chosen at the option of the manufac- 
turer), and a vehicle equipped with one or more 
brake power units shall meet the requirements of 
either S5. 1.3.1, S5. 1.3.3, or S5. 1.3.4 (chosen at the 



option of the manufacturer). (46 F.R. 55 — January 
2, 1981. Effective: 9/1/83)] 

55. 1.3.1 The service brakes on a vehicle equipped 
with one or more brake power assist units or brake 
power units, with one such unit inoperative and 
depleted of all resei^ve capability, shall be capable 
of stopping a vehicle from 60 mph within the cor- 
responding distance specified in Column IV of 
Table II. 

55.1.3.2 Brake power assist units. The service 
brakes on a vehicle equipped with one or more 
brake power assist units, with one such unit inop- 
erative, shall be capable of stopping a vehicle 
from 60 mph — 

(a) In six consecutive stops at an average 
deceleration for each stop that is not lower than 
that specified in Column I of Table III, when the 
inoperative unit is not initially depleted of all 
reserve capability; and 

[(b) In a final stop, at an average deceleration 
that is not lower than 7 fpsps for passenger cars 
(equivalent stopping distance 554 feet) or 6 fpsps 
for vehicles other than passenger cars (equivalent 
stopping distance 646 feet), as applicable, when 
the inoperative unit is depleted of all reserve 
capacity. (46 F.R. 55 — January 2, 1981. Effective: 
9/1/83)] 



[TABLE II— STOPPING DISTANCES 





STOPPING DISTANCE IN FEET FOR TESTS INDICATED 






1 


II 


111 


IV 


Vehicle test 

speed (miles 

per hour) 


1st (prebumish) power and 4ih ef- 
fectiveness: spike effectiveness 
check 


2d 
effectiveness 


3d (lightly loaded vehicle) 
effectiveness 


Inoperative brake 
power and power as- 
sist unit; partial failure 




(a) (b) (c) (d) 


(b) 

(a) and (d) 

(c) 


(a) (b) (c) (d) 


(b) 

(a) and (d) 

(c) 



30 '57 '65 '-69 (1st) '88 '54 '57 '81 51 57 65 81 114 130 170 

'-65 (4th 

and 
spike) 

'72 

35 74 83 91 132 70 74 132 67 74 83 132 155 176 225 

40 96 108 119 173 91 96 173 87 96 108 173 202 229 288 

45 121 137 150 218 115 121 218 110 12! 137 218 257 291 358 

50 150 169 185 264 142 150 264 135 150 169 264 317 359 435 

55 181 204 224 326 172 181 326 163 181 204 326 383 433 530 

60 '216 '242 '267 '388 '204 '216 '388 '194 '216 '242 '388 '456 '517 '613 

80 '405 '459 '510 NA '383 NA NA NA NA NA NA NA NA NA 

95 1607 NA NA NA NA NA NA NA NA NA NA NA NA NA 

100 '673 NA NA NA NA NA NA NA NA NA NA NA NA NA 

' Distances for specified tests. -Applicable to school buses only. NA=Not applicable. 

Note — (a) passenger cars; (b) vehicles other than passenger cars with GVWR of less than 8.000 lbs; (cl vehicles with GVWR of not less 

than 8,000 lbs. and not more than 10,000 lbs.; (d) vehicles with GVWR greater than 10.000 lbs. (46 F.R. 55— January 2, 1981. Effective: 9/ 
1/83)1 



PART 571; S 105-3 



(Rev. 1/2/81) 



[TABLE III— INOPERATIVE BRAKE POWER ASSIST AND BRAKE POWER UNITS 

Average Deceleration, FPSPS Equivalent Stopping Distance, Feet 

StoD No Column 1 — brake power Column 2 — brake power Column 3 — brake power Column 4 — brake 

" ' assist unit assist power unit 

(a) (b) and (c) (a) (b) and (c) (a) (b) and (c) (a) (b) and (c) 

1 16.0 14.0 16.0 13.0 242 277 242 298 

2 12.0 12.0 13.0 11.0 323 323 298 3-^2 

3 10.0 10.0 12.0 10.0 388 388 323 388 

4 9.0 8.5 11.0 9.5 431 456 352 409 

5 8.0 7.5 10.0 9.0 484 517 388 431 

6 7.5 6.7 9.5 8.5 517 580 409 456 

7 '7.0 '6.0 9.0 8.0 554 646 431 484 

8 NA NA 8.5 7.5 NA NA 456 517 

9 NA NA 8.0 7.0 NA NA 484 554 

10 NA NA 7.5 6.5 NA NA 517 596 

11 NA NA '7.0 '6.0 NA NA 554 646 

'Depleted, (a) passenger cars; (b) vehicles other than passenger cars with GVWR of 10.000 lbs. or less; (c) vehicles with GVWR greater 
than 10,000 lbs.; NA=Not Applicable. (46 F.R. 55— January 29'; 1981. Effective: 9/1/83)] 



55.1.3.3 Brake power units. The service brakes 
of a vehicle equipped with one or more brake 
power units with an accumulator-type reserve sys- 
tem, with any one failure in any one unit, shall be 
capable of stopping the vehicle from 60 mph: 

(a) In 10 consecutive stops at an average decel- 
eration for each stop that is not lower than that 
specified in Column II of Table III, when the unit 
is not initially depleted of all reserve capability; 
and 

[(b) In a final stop, at an average deceleration 
that is not lower than 7 fpsps for passenger cars 
(equivalent stopping distance 554 feet) or 6 fpsps 
for vehicles other than passenger cars (equivalent 
stopping distance 646 feet), as applicable, when 
the inoperative unit is depleted of all reserve 
capacity. (46 F.R. 55— January 2, 1981. Effective: 
9/1/83)] 

55.1.3.4 Bral<e power assist and bral<e power 
units. The service brake of a vehicle equipped 
with one or more brake power assist units or brake 
power units with a backup system, with one brake 
power assist unit or brake power unit inoperative 
and depleted of all reserve capability and with 
only the backup system operating in the failed 
subsystem, shall be capable of stopping the 
vehicle from 60 mph in 15 consecutive stops at an 
average deceleration for each stop that is not 
lower than 12 fpsps (equivalent stopping distance 
323 feet). 

S5.1.4 Fade and recovery. The service brakes 
shall be capable of stopping each vehicle in two 
fade and recovery tests as specified below. 



55. 1.4.1 The control force used for the base line 
check stops or snubs shall be not less than 10 
pounds, nor more than 60 pounds, except that the 
control force for a vehicle with a GVWR of 
10,000 pounds or more may be between 10 
pounds and 90 pounds. 

55.1.4.2 (a) Each vehicle with GVWR of 10,000 
pounds or less shall be capable of making five 
fade stops (10 fade stops on the second test) from 
60 mph at a deceleration not lower than 15 fpsps 
for each stop, followed by five fade stops at the 
maximum decleration attainable from 5 to 15 
fpsps. 

(b) Each vehicle with a GVWR greater than 
10,000 pounds shall be capable of making 10 fade 
snubs (20 fade snubs on the second test) from 40 
mph to 20 mph at 10 fpsps for each snub. 

55.1.4.3 (a) Each vehicle with a GVWR of 10,000 
pounds or less shall be capable of making five 
recovery stops from 30 mph at ten fpsps for each 
stop, with a control force application that falls 
within the following maximum and minimum lim- 
its: 

(1) A maximum for the first four recovery 
stops of 150 pounds, and for the fifth stop, of 20 
pounds more than the average control force for 
the baseline check; and 

(2) A minimum of — 

(A) The average control force for the base- 
line check minus 10 pounds, or 

(B) The average control force for the base- 
line check times 0.60, 

whichever result is lower (but in no case lower 
than 5 pounds). 



(Rev. 1/2/81) 



PART 571; S 105^ 



(b) Each vehicle with a GVWR of more than 
10,000 pounds shall be capable of making five 
recovery snubs from 40 mph to 20 mph at 10 
fpsps of each snub, with a control force applica- 
tion that falls within the following maximum and 
minimum limits: 

(1) A maximum for the first four recovery 
snubs of 150 pounds, and for the fifth snub, of 20 
pounds more than the average control force for 
the baseline check (but in no case more than 100 
pounds); and 

(2) A minimum of— 

(A) The average control force for the base- 
line check minus 10 pounds, or 

(B) The average control force for the base- 
line check times 0.60, whichever is lower (but 
in no case lower than 5 pounds). 

S5.1.5 Water recovery. The service brakes shall 
be capable of stopping each vehicle in a water 
recovery test, as specified below. 

55. 1.5.1 The control force used for the baseline 
check stops or snubs shall be not less than 10 
pounds, nor more than 60 pounds, except that the 
control force for a vehicle with a GVWR of 
10,000 pounds or more may be between 10 and 90 
pounds. 

55.1.5.2 (a) After being driven for 2 minutes at a 
speed of 5 mph in any combination of forward 
and reverse directions tlirough a trough having a 
water depth of 6 inches, each vehicle with a 
GVWR of 10,000 pounds or less shall be capable 
of making five recovery stops from 30 mph at 10 
fpsps for each stop with a control force application 
that falls within the following maximum and mini- 
mum limits: 

(1) A maximum for the first four recovery 
stops of 150 pounds, and for the fifth stop, of 45 
pounds more than the average control force for 
the baseline check (but in no case more than 90 
pounds, except that the maximum control force 
for the fifth stop in the case of a vehicle manufac- 
tured before September 1, 1976, shall be not more 
than plus 60 pounds of the average control force 
for the baseline check) (but in no case more than 
110 pounds). 

(2) A minimum of — 

(A) The average control force for the base- 
line check minus 10 pounds, or 



(B) The average control force for the base- 
line check times 0.60, 
whichever result is lower (but in no case lower 
than 5 pounds). 

(b) After being driven for 2 minutes at a speed 
of 5 mph in any combination of forward and 
reverse directions through a trough having a water 
depth o 6 inches, each vehicle with a GVWR of 
more than 10,000 pounds shall be capable of 
making five recovery snubs from 40 mph to 20 
mph at 10 fpsps for each snub, with a control 
force application that falls within the following 
maximum and minimum limits: 

(1) A maximum for the first four recovery 
stops of 150 pounds, and for the fifth stop, of 60 
pounds more than the average control force for 
the baseline check (but in no case more than 110 
pounds); and 

(2) A minimum of — 

(A) The average control force for the base- 
line check minus 10 pounds, or 

(B) The average control force for the base- 
line check times 0.60, whichever is lower (but 
in no case lower than 5 pounds). 

S5.1.6 Spike stops. Each vehicle with a GVWR 
of 10,000 lbs. or less shall be capable of making 
10 spike stops from 30 mph, followed by 
effectiveness (check) stops from 60 mph, at least 
one of which shall be within a corresponding stop- 
ping distance specified in Column I of Table II. 

S5.2 Parking brake system. Each vehicle [with 
a GVWR of 10,000 lbs. or less and each school 
bus with a GVWR greater than 10.000 lbs.] shall 
be manufactured with a parking brake system of 
a friction type with a solely mechanical means to 
retain engagement, which shall under the condi- 
tions of S6, when tested according to the proce- 
dures specified in S7, meet the requirements 
specified in S5.2.1, S5.2.2, or S5.2.3 as appro- 
priate, with the system engaged — 

(a) In the case of a [vehicle with a GVWR of 
10,000 lbs. or less] with a force applied to the 
control not to exceed 125 pounds for a foot-oper- 
ated system and 90 pounds for a hand-operated 
system; and 

(b) In the case of a school bus [with a GVWR 
greater than 10,000 lbs.] with a force applied to 
the control not to exceed 150 pounds for a foot- 
operated system and 125 pounds for a hand-oper- 



PART571; S 105-5 



(Rev. 12/21/81) 



ated system. (46 F.R. 61887— December 21, 1981. 
Effective: 9/1/83) 

55.2.1 Except as provided in S5.2.2, the parking 
brake system on a [passenger car and on a school 
bus] with a GVWR of 10,000 pounds or less shall 
be capable of holding the vehicle stationary (to the 
limit of traction on the braked wheels) for 5 min- 
utes in both a forward and reverse direction on a 
30 percent grade. (46 F.R. 61887— December 21, 
1981. Effective: 9/1/83) 

55.2.2 A vehicle of a type described in S5.2.1 at 
the option of the manufacturer may meet the 
requirements of S5.2.2.1. S5.2.2.2, and S5.2.2.3 
instead of the requirements of S5.2.1 if: 

(a) The vehicle has a transmission or trans- 
mission control which incorporates a parking 
mechanism, and 

(b) The parking mechanism must be engaged 
before the ignition key can be removed. 

55.2.2.1 The vehicle's parking brake and parking 
mechanism, when both are engaged, shall be 
cpable of holding the vehicle stationary (to the 
limit of traction of the braked wheels) for 5 min- 
utes, in both forward and reverse directions, on a 
30 percent grade. 

55.2.2.2 The vehicle's parking brake, with the 
parking mechanism not engaged, shall be capable 
of holding the vehicle stationary for 5 minutes, in 
both forward and reverse directions, on a 20 per- 
cent grade. 

55.2.2.3 With the parking mechanism engaged 
and the parking brake not engaged, the parking 
mechanism shall not disengage or fracture in a 
manner permitting vehicle movement, when the 
vehicle is impacted at each end, on a level surface, 
by a barrier moving at IVi mph. 

55.2.3 The parking brake system on a multipur- 
pose passenger vehicle, truck, and bus (other than 
a school bus) with a GVWR greater than 10,000 
pounds shall be capable of holding the vehicle 
stationary for 5 minutes, in both forward and 
reverse directions, on a 20 percent grade. 

S5.3 Brake system Indicator lamp. Each 
vehicle shall have one or more brake system 
indicator lamps, mounted in front of and in clear 
view of the driver, which meet the requirements of 



S5.3.1 through S5.3.5. However, the options pro- 
vided in S5.3.1(a) shall not apply to a vehicle 
manufactured without a split service brake system; 
such a vehicle shall, to meet the requirements of 
S5.3.1(a), be equipped with a warning indicator 
that activates under the conditions specified in 
S5. 3. 1(a)(4). This warning indicator shall, instead 
of meeting the requirements of S5.3.2 through 
S5.3.5, activate (while the vehicle remains capable 
of meeting the requirements of S5. 1.2.2 and the 
ignition switch is in the "on" position) a continu- 
ous or intermittent audible signal and a flashing 
warning light displaying the words "STOP — 
BRAKE FAILURE" in block capital letters not 
less than one-quarter of an inch in height. 

55.3.1 An indicator lamp shall be activated when 
the ignition (start) switch is in the "on" ("run") 
position and whenever any of conditions (a), (c), 
or (d) occur, or, at the option of the manufacturer, 
whenever any of conditions (b), (c), or (d) occur: 

(a) A gross loss of pressure (such as caused by 
rupture of a brake line but not by a structural fail- 
ure of a housing that is common to two or more 
subsystems) due to one of the following condi- 
tions (chosen at the option of the manufacturer): 

(1) Before or upon application of a differen- 
tial pressure of not more than 225 Ib/in^ 
between the active and failed brake system 
measured at a master cylinder outlet or a slave 
cylinder outlet. 

(2) Before or upon application of 50 pounds 
of control force upon a fully manual service 
brake. 

(3) Before or upon application of 25 pounds 
of control force upon a service brake with a 
brake power assist unit. 

(4) When the supply pressure in a brake 
power unit drops to a level not less than one- 
half of the normal system pressure. 

(b) A drop in the level of brake fluid in any 
master cylinder reservoir compartment to less 
than the recommended safe level specified by the 
manufacturer or to one-fourth of the fluid capac- 
ity of the reservoir compartment, whichever is 
greater. 

(c) A total functional electrical failure in an 
antilock or variable proportioning brake system. 

(d) Application of the parking brake. 

55.3.2 [(a) Except as provided in paragraph (b) of 
this section, all indicator lamps shall be activated 



(Rev. 12/21/81) 



PART 571: S 105-6 



as a check of lamp function either when the igni- 
tion (start) switch is turned to the "on" (run) 
position when the engine is not running, or when 
the ignition (start) switch is in a position between 
"on" (run) and "start" that is designated by the 
manufacturer as a check position. 

(b) The indicator lamps need not be activated 
when a starter interlock is in operation. (54 F.R. 
40080— September 29, 1989. Effective: September 
1, 1991)] 

55.3.3 Each indicator lamp activated due to a 
condition specified in S5.3.1 shall remain acti- 
vated as long as the condition exists, whenever the 
ignition (start) switch is in the "on" ("run") 
position, whether or not the engine is running. 

55.3.4 When an indicator lamp is activated it may 
be steady burning or flashing. 

S5.3.5(a) (a) Each indicator lamp shall display 
word, words, or abbreviation, in accordance with 
the requirements of Standard No. 101 (49 CFR 
571.101) and/or this section, which shall have let- 
ters not less than '/s-inch high and be legible to 
the driver in daylight when lighted. 

(b) If a single common indicator is used, the 
lamp shall display the word "Brake". The letters 
and background of a single common indicator 
shall be of contrasting colors, one of which is red. 

(c)(1) I separate indicator lamps are used for 
one or more than one of the functions described 
in S5.3.1(a) through S5.3.1(d), the display shall, 
except as provided in (c)(1) (A) through (D) of 
this section, include the word "Brake" and 
appropriate aditional labeling. 

(A) If a separate indicator lamp is provided for 
gross loss of pressure, the words "Brake Pres- 
sure" shall be used for S5.3.1(a). 

(B) If a separate indicator lamp is provided for 
low brake fluid, the words "Brake Fluid" shall 
be used for S5.3.1(b), except for vehicles using 
hydraulic system mineral oil. 

(C) If a separate indicator lamp is provided for 
an anti-lock system, the single word "Antilock" 
or "Anti-lock" may be used for S5.3.1(c). 

(D) If a separate indicator lamp is provided for 
application of the parking brake, the single word 
"Park" may be used for S5.3.1(d). 

(2) Except for a separate indicator lamp for an 
anti-lock system, the letters and background of 
each separate indicator lamp shall be of contrast- 
ing colors, one of which is red. The letters and 



background of a separate indicator lamp for an 
anti-lock system shall be of contrasting colors, 
one of which is yellow. 

S5.4 Reservoirs. 

55.4.1 IVIaster cylinder reservoirs. A master 
cylinder shall have a reservoir compartment for 
each service brake subsystem serviced by the mas- 
ter cylinder. Loss of fluid from one compartment 
shall not result in a complete loss of brake fluid 
from another compartment. 

55.4.2 Reservoir capacity. Reservoirs, whether 
for master cylinders or other type systems, shall 
have a total minimum capacity equivalent to the 
fluid displacement resulting when all the wheel 
cylinders or caliper pistons serviced by the res- 
ervoirs move from a new lining, fully retracted 
position (as adjusted initially to the manufacturer's 
recommended setting) to a fully worn, fully 
applied position, as determined in accordance with 
S7. 18(c) of this standard. Reservoirs shall have 
completely separate compartments for each sub: 
system except that in reservoir systems utilizing a 
portion of the reservoir for a common supply to 
two or more subsystems, individual partial 
compartments shall each have a minimum volume 
of fluid equal to at least the volume displaced by 
the master cylinder piston servicing the subsystem, 
during a full stroke of the piston. Each brake 
power unit reservoir servicing only the brake sys- 
tem shall have a minimum capacity equivalent to 
the fluid displacement required to charge the sys- 
tem piston(s) or accumulator(s) to normal operat- 
ing pressure plus the displacement resulting when 
all the wheel cylinders or caliper pistons serviced 
by the reservoir or accumulator(s) move from a 
new lining fully retracted position (as adjusted ini- 
tially to the manufacturer's recommended setting) 
to a fully worn, fully applied position. 

55.4.3 Reservoir labeling. Each vehicle shall 
have a brake fluid warning statement that reads as 
follows, in letters at least Vs of an inch high: 
"WARNING, Clean filler cap before removing. 

Use only fluid from a 

sealed container." (Inserting the recommended 
type of brake fluid as specified in 49 CFR 
§571.116, e.g., "DOT 3".) The lettering shall 
be— 

(a) Permanently affixed, engraved, or 
embossed; 



PART 571: S 105-7 



(Rev. 9/29/89) 



(b) Located so as to be visible by direct view, 
either on or within 4 inches of the brake fluid res- 
ervoir filler plug or cap; and 

(c) Of a color that contrasts with its back- 
ground, if it is not engraved or embossed. 

55.5 Antilock and variable proportioning 
brake systems. In the event of failure (structural 
or functional) in an antilock or variable propor- 
tioning brake system the vehicle shall be capable 
of meeting the stopping distance requirements 
specified in S5.1.2 for service brake system partial 
failure. 

55.6 Brake system Integrity. Each vehicle shall 
be capable of completing all performance require- 
ments of S5 without — 

(a) Detachment or fracture of any component 
of the braking system, such as brake springs and 
brake shoe or disc pad facing, other than minor 
cracks that do not impair attachment of the fric- 
tion facing. All mechanical components of the 
braking system shall be intact and functional. 
Friction facing tearout (complete detachment of 
lining) shall not exceed 10 percent of the lining 
on any single frictional element. 

(b) Any visible brake fluid or lubricant on the 
friction surface of the brake, or leakage at the 
master cylinder or brake power unit reservoir 
cover, seal, and filler openings. 

S6. Test conditions. The performance require- 
ments of S5 shall be met under the following 
conditions. Where a range of conditions is speci- 
fied, the vehicle shall be capable of meeting the 
requirements at all points within the range. 

S6.1 Vehicle weight. 

S6.1.1 Other than tests specified at lightly loaded 
vehicle weight in S7.7, S7.8, and S7.9, the vehicle 
is loaded to its GVWR such that the weight on 
each axle as measured at the tireground interface 
is in proportion to its GAWR, except that [each] 
fuel tank is filled to any level from 100 percent 
of capacity (corresponding to full GVWR loading) 
to 75 percent. (46 F.R. 55— January 2, 1981. Effec- 
tive: 9/1/83) 

However, if the weight on any axle of a vehicle 
at lightly loaded vehicle weight exceeds the axle's 
proportional share of the gross vehicle weight rat- 
ing, the load required to reach GVWR is placed 



so that the weight on that axle remains the same 
as at lightly loaded vehicle weight. 

S6.1.2 For the applicable tests specified in S7.7, 
S7.8, and S7.9, vehicle weight is lightly loaded 
vehicle weight, with the added weight distributed 
in the front passenger seat area in passenger cars 
[multipurpose vehicles and trucks] and in the 
area adjacent to the driver's seat in buses. (46 F.R. 
55— January 2, 1981. Effective: 9/1/83) 

56.2 Test loads. [Reserved.] 

56.3 Tire Inflation pressure. Tire inflation pres- 
sure is the pressure recommended by the vehicle 
manufacturer for the GVWR of the vehicle. 

56.4 Transmission selector control. For S7.3, 

S7.5, S7.8, S7.15, S7.17, S7.1 1.1.2, S7.1 1.2.2, 
S7. 11.3.2, and as required for S7.13, the trans- 
mission selector control is in neutral for all decel- 
erations. For all other tests during all decelera- 
tions, the transmission selector is in the control 
position, other than overdrive, recommended by 
the manufacturer for driving on a level surface at 
the applicable test speed. To avoid engine stall 
during tests required to be run in gear a manual 
transmission may be shifted to neutral (or the 
clutch disengaged) when the vehicle speed 
decreases to 20 mph. 

56.5 Engine. Engine idle speed and ignition tim- 
ing settings are according to the manufacturer's 
recommendations. If the vehicle is equipped with 
an adjustable engine speed governor, it is adjusted 
according to the manufacturer's recommendation. 

56.6 Vehicle Openings. All vehicle openings 
(doors, windows, hood, trunk, convertible top, 
cargo doors, etc.) are closed except as required for 
instrumentation purposes. 

56.7 Ambient temperature. The ambient 
temperature is any temperature between 32° F. 
and 100° F. 

56.8 Wind velocity. The wind velocity is zero. 

56.9 Road surface. Road tests are conducted on 
a 12-foot-wide, level roadway having a skid num- 
ber of 81. Burnish stops are conducted on any sur- 
face. The parking brake test surface is clean, dry 
smooth Portland cement concrete. 



(Rev. 1/2/81) 



PART 571; S 105-8 



S6.10 Vehicle position. The vehicle is aligned 
in the center of the roadway at the start of each 
brake application. Stops, other than spike stops, 
are made without any part of the vehicle leaving 
the roadway. Except as noted below, stops are 
made without lockup of any wheel at speeds 
greater than 10 mph. There may be controlled 
lockup on an antilock-equipped axle, and lockup 
of not more than one wheel per vehicle, uncon- 
trolled by an antilock system. [Dual wheels on 
one side of an axle are considered a single 
wheel.] Locked wheels at speeds greater than 10 
mph are allowed during spike stops (but not spike 
check stops), partial failure stops, and inoperative 
brake power or power assist unit stops. (46 F.R. 
55)— January 2, 1981. Effective: 9/1/83) 

0.295 DIA MAX- 
0.12 DIA- 



S6.1 1 Thermocouples. The brake temperature is 
measured by plug-type thermocouples installed in 
the approximate center of the facing length and 
width of the most heavily loaded shoe or disc pad, 
one per brake, as shown in Figure 1. A second 
thermocouple may be installed at the beginning of 
the test sequence if the lining wear is expected to 
reach a point causing the first thermocouple to 
contact the metal rubbing surface of a drum or 
rotor. For center-grooved shoes or pads, 
thennocouples are installed within one-eighth of 
an inch to one-quarter inch of the groove and as 
close to the center as possible. 




CO DRILL NO. 31 
0.100 MAX DEPTH 
BEFORE GRIND 



0.040 RECESS UNDER 
GROUND SURFACE 



GRIND TO 1/8- 
MAX BEFORE 
PLACING IN LINING 




0.040 RECESS UNDER 
GROUND SURFACE 



Figure 1 — Typical Plug Thermocuple Installations 



PART 571; S 105-9 



(Rev. 1/2/81) 



56.12 Initial brake temperature. Unless other- 
wise specified, the brake temperature is 150° F to 
200° F. 

56.13 Control forces. Unless otherwise speci- 
fied, the force applied to a brake control is not 
less than 15 pounds and not more than 150 
pounds. 

S7. Test procedures and sequence. [Each 
vehicle shall be capable of meeting all the 
applicable requirements of S5 when testing 
according to the procedures and in the sequence 
set forth below, without replacing any brake sys- 
tem part or making any adjustments to the brake 
system other than as permitted in burnish and 
rebumish procedures and in S7.9 and S7.10. (For 
vehicles only having to meet the requirements of 
S5.1.2 and S5.1.3 in section S5.1, the applicable 
test procedures and sequence are S7.1, S7.2, S7.4, 
S7.9, S7.10, and S7.18. However, at the option of 
the manufacturer, the following test procedures 
and sequence may be conducted: S7.1, S7.2, S7.3, 
S7.4, S7.5, S7.6, S7.7, S7.8, S7.9. S7.10 and 
S7.18. The choice of this option shall not be con- 
strued as adding to the requirements specified in 
S5.1.2 and S5.1.3.) For vehicles manufactured 
before September 1, 1991, automatic adjusters 
may be locked out, at the option of the manufac- 
turer, when the vehicle is prepared for testing. If 
this option is selected, adjusters must remain 
locked out for the entire sequence of tests. For 
vehicles manufactured on or after September 1, 
1991, automatic adjusters must remain activated at 
all times. A vehicle shall be deemed to comply 
with the stopping distance requirements of S5.1 if 
all least one of the stops at each speed and load 
specified in each of S7.3, S7.5, S7.8, S7.9, S7.10. 
S7.15, or 57.17 (check stops) is made within a 
stopping distance that does not exceed the cor- 
responding distance specified in Table II. When 
the transmission selector control is required to be 
in neutral for a deceleration, a stop or snub shall 
be obtained by the following procedures: (1) 
Exceed the test speed by 4 to 8 mph; (2) close the 
throttle and coast in gear to approximately 2 mph 
above the test speed; (3) Shift to neutral; and (4) 
when the test speed is reached apply the service 
brakes. (54 F.R. 40080— September 29, 1989. Effec- 
tive: September 1, 1991)] 

S7.1 Brake warming. Each passenger car, multi- 
purpose passenger vehicle, truck and bus shall be 



equipped with a headlighting ststem designed to 
conform to the requirements of S7.3, S7.4, S7.5, 
or S7.6. 

57.2 Pretest Instrumentation check. Conduct a 
general check of instrumentation by making not 
more than 10 stops from a speed of not more than 
30 mph, or 10 snubs from a speed of not more 
than 40 mph to 10 mph, at a deceleration of not 
more than 10 fpsps. If instrument repair, replace- 
ment, or adjustment is necessary, make not more 
than 10 additional stops or snubs after such repair, 
replacement, or adjustment. 

57.3 Service brake system — first (reburnish) 
effectiveness test. Make six stops from 30 mph. 
Then make six stops from 60 mph. 

57.4 Service brake system — burnish proce- 
dure. 

57.4.1 Vehicles with GVWR of 10,000 pounds 
or less. 

57.4.1.1 Burnish. Burnish the brakes by making 
200 stops from 40 mph at 12 fpsps (the 150 pound 
control force limit does not apply here). The inter- 
val from the start of one service brake application 
to the start of the next shall be either the time nec- 
essary to reduce the initial brake temperature to 
between 230° F and 270° F, or the distance of 1 
mile, whichever occurs first. Accelerate to 40 mph 
after each stop and maintain that speed until mak- 
ing the next stop. 

57.4.1.2 Brake adjustment— post burnish. 

[After burnishing, adjust the brakes in accordance 
with the manufacturer's published recommenda- 
tions. 54 F.R. 40080— September 29, 1989. 
Effective: September 1, 1991.)] 

57.4.2 Vehicles with GVWR greater than 
10,000 pounds. 

S7.4.2.1 Burnish. Vehicles manufactured before 
September 1, 1993 may be burnished according to 
the procedures set forth in S 7.4.2. 1(a) or 
S 7.4.2. 1(b) of this section, at the manufactures 
option. Vehicles manufactured on or after Septem- 
ber 1, 1993 shall be burnished according to the 
procedures set forth in S 7.4.2.1(b) of this section, 
(a) Burnish the brakes by making 500 snubs at 
10 fsps in the sequence specified in Table IV and 



(Rev. 9/29/89) 



PART 571; S 105-10 



within the speed ranges indicated. Except where 
an adjustment is specified, after each braice 
application accelerate to the next speed specified 
and maintain that speed until making the next 
brake application at a point 1 mile from the initial 
point of the previous brake application. If a 
vehicle cannot attain any speed specified in 1 
mile, continue to accelerate until the speed speci- 
fied is reached or until the vehicle has traveled 
1.5 miles from the initial point of the previous 
brake application, whichever occurs first. If dur- 
ing any of the brake applications specified in 
Table IV the hottest brake reaches 500° F. make 
the remainder of the 500 applications from that 
snub condition, except that a higher or lower snub 
condition shall be followed (up to the 60 mph ini- 
tial speed) as necesary to maintain a hottest brake 
temperature of 500° F±50° F. However, if at a 
snub condition of 40 to 20 mph, the temperature 
of the hottest brake exceeds 550° F, make the 
remainder of the 500 brake applications from that 
snub condition, without regard to the brake 
temperature. The brakes shall be adjusted three 
times during the burnish procedure, in accordance 
with the manufacturer's recommendations, after 
125, 250, and 375 snubs. 

Table IV 

Snub condi- 

r. . c u tions (highest 

Series Snubs , '=^ ,. 

speed indi- 
cated) 

1 175 40 to 20 mph 

2 25 45 to 20 mph 

3 25 50 to 20 mph 

4 25 55 to 20 mph 

5 250 60 to 20 mph 

(b) Burnish the brakes by making 500 snubs 
between 40 mph and 20 mph at a deceleration 
rate of 10 fsps. Except where an adjustment is 
specified, after each brake application accelerate 
to 40 mph and maintain that speed until making 
the next brake application at a point 1 mile from 
the initial point of the previous brake application. 
If the vehicle cannot attain a speed of 40 mph in 
1 mile, continue to accelerate until the vehicle 
reaches 40 mph or until the vehicle has traveled 
1.5 miles from the initial point of the previous 
brake application, whichever occurs first. The 
brakes shall be adjusted three times during the 
burnish procedure, the accordance with the manu- 
facturer's recommendations, after 125, 250, and 
375 snubs. 



S7.4.2.2 [Brake adjustment — post burnish. After 
burnishing, adjust the brakes in accordance with 
the manufacturer's published recommendations. 
(54 F.R. 40080— September 29, 1989. Effective: 
September 1, 1991)] 

57.5 Service brake system — second effective- 
ness test. Repeat S7.3. Then (for passenger cars) 
and other vehicles with a GVWR of 10,000 lbs. 
or less make four stops from 80 mph if the speed 
attainable in 2 miles is not less than 84 mph. 

57.6 First reburnish. Repeat S7.42 except make 
35 burnish stops or snubs. In the case of vehicles 
burnished in accordance with S7.4.2.1(a) of this 
section, reburnish the vehicle by making 35 snubs 
from 60 mph to 20 mph, but if the hottest brake 
reaches 500° F±50° F make the remainder of the 
brake applications from the highest snub condition 
listed in Table IV that will maintain the hottest 
brake temperature a 500° F±50° F. If at a snub 
condition of 40 to 20 mph, the temperature of the 
hottest brake exceeds 550° F, make the remainder 
of the 35 brake applications from the snub condi- 
tion without regard to brake temperature. 

57.7 Parl<ing bral<e test. The parking brake 
tests for any vehicle on different grades, in dif- 
ferent directions, and for different loads may be 
conducted in any order. The force required for 
actuation of a hand-operated brake system shall be 
measured at the center of the hand grip area or at 
a distance of 1 V2 inches from the end of the actu- 
ation lever, as illustrated in Figure 2. 



S7.7 Test procedure for requirements of 
S5.2.1. 

57.7.1.1 Condition the parking brake friction ele- 
ments so that the temperature at the beginning of 
the test is at any level not more than 150° F (when 
the temperature of components on both ends of an 
axle are averaged). 

57.7.1.2 Drive the vehicle, loaded to GVWR, onto 
the specified grade with the longitudinal axis of 
the vehicle in the direction of the slope of the 
grade, stop the vehicle and hold it stationary by 
application of the service brake control, and place 
the transmission in neutral. 



PART 571; S 105-11 



(Rev. 9/29/89) 



R-t 




•L" TYPE 



"T" TYPE 



3z: 



* 



— »J L_11/2 

F 
LEVER TYPE A 




F : APPLIED 
R = REACTION 



LEVER TYPE B 



Figure 2 — Location for IVIeasuring Bral<e Application Force (Hand Brake) 



57.7.1.3 With the vehicle held stationary by 
means of the service brake control, apply the park- 
ing brake by a single application of the force 
specified in (a) or (b), except that a series of 
applications to achieve the specified force may be 
made in the case of a parking brake system design 
that does not allow the application of the specified 
force in a single application: 

[(a) In the case of a passenger car or other 
vehicle with a GVWR of 10,000 lbs. or less, not 
more than 125 pounds for a foot-operated system, 
and not more than 90 pounds for a hand-operated 
system; and 

(b) In the case of a school bus with a GVWR 
greater than 10,000 lbs. not more than 150 
pounds for a foot-operated system, and not more 
than 125 pounds for a hand-operated system. (46 
F.R. 55— January 2, 1981. Effective: 9/1/83)] 

57.7.1.4 Following the application of the parking 
brake in accordance with S7.7.1.3, release all 
force on the service brake control and commence 
the measurement of time if the vehicle remains 
stationary. If the vehicle does not remain station- 
ary, reapplication of the service brake to hold the 
vehicle stationary, with reapplication of a force to 
the parking brake control at the level specified in 
S7. 6. 1.3(a) or (b) as appropriate for the vehicle 
being tested (without release of the ratcheting or 
other holding mechanism of the parking brake) 
may be used twice to attain a stationary position. 



57.7.1.5 Following observation of the vehicle in a 
stationary condition for the specified time in one 
direction, repeat the same test procedure with the 
vehicle orientation in the opposite direction on the 
specified grade. 

57.7.1 .6 Check the operation of the parking brake 
application indicator required by S5.3.1(d). 



57.7.2 Test procedures for requirements of 
S5.2.2. (a) Check that transmission must be placed 
in park position to release key; 

(b) Test as in S7.7.1, except in addition place 
the transmission control to engage the parking 
mechanism; and 

(c) Test as in S7.7.1 except on a 20 percent 
grade, with the parking mechanism not engaged. 

57.7.3 Ligiitiy loaded vehicle. Repeat S7.7.1 or 
S7.7.2 as applicable except with the vehicle at 
lightly loaded vehicle weight. 

57.7.4 Non-service brake type parking brake 
systems. For vehicles with parking brake systems 
not utilizing the service brake friction elements, 
burnish the friction elements of such systems prior 
to parking brake tests according to the manufac- 
turer's published recommendations as furnished to 
the purchaser. If no recommendations are fur- 
nished, run the vehicle in an unbumished condi- 
tion. 



(Rev. 1/2/81) 



PART 571; S 105-12 



57.8 Service brake system-lightly loaded 
vehicle (third effectiveness) test. Make six stops 
from 60 tnph with vehicle at Hghtly loaded vehicle 
weight. [This test is not applicable to a vehicle 
which both has a GVWR of not less than 8,000 
pounds and not greater than 10,000 pounds and is 
not a school bus. (46 F.R. 55 — January 2, 1981. 
Effective: 9/1/83)] 

57.9 Service brake system test-partial failure. 

57.9.1 With the vehicle at lightly loaded vehicle 
weight, alter the service brake system to produce 
any one rupture or leakage type of failure, other 
than a structural failure of a housing that is com- 
mon to two or more subsystems. Determine the 
control force, pressure level, or fluid level (as 
appropriate for the indicator being tested) nec- 
essary to activate the brake system indicator lamp. 
Make 4 stops if the vehicle is equipped with a 
split service brake system, or 10 stops if the 
vehicle is not so equipped, each from 60 mph, by 
a continuous application of the service brake con- 
trol. Restore the service brake system to normal at 
completion of this test. 

57.9.2 Repeat S7.9.1 for each of the other sub- 
systems. 

57.9.3 Repeat 57.9.1 and 57.9.2 with vehicle at 
GVWR. Restore the service brake system to nor- 
mal at completion of this test. 

57.9.4 (For vehicles with antilock and/or variable 
proportioning brake systems.) With vehicle at 
GVWR, disconnect functional power source, or 
otherwise render antilock system inoperative. Dis- 
connect variable proportioning brake system. 
Make four stops, each from 60 mph. If more than 
one antilock or variable proportioning brake sub- 
system is provided, disconnect or render one sub- 
system inoperative and run as above. Restore sys- 
tem to normal at completion of this test. Repeat 
for each subsystem provided. Determine whether 
the brake system indicator lamp is activated when 
the electrical power source to the antilock or vari- 
able proportioning unit is disconnected. 

57.10 Service brake system — Inoperative 
brake power unit or brake power assist unit 
test. (For vehicles equipped with brake power unit 
or brake power assist unit.) 



57.10.1 Regular procedure. (This test need not 
be run if the option in S7.10.2 is selected.) On 
vehicles with brake power assist units, render the 
brake power assist unit inoperative, or one of the 
brake power assist unit subsystems if two or more 
subsystems are provided by disconnecting the rel- 
evant power supply. Exhaust any residual brake 
power reserve capability of the disconnected sys- 
tem. On vehicles with brake power units, dis- 
connect the primary source of power. Make four 
stops, each from 60 mph, by a continuous applica- 
tion of the service brake control. Restore the sys- 
tem to normal at completion of this test. For 
vehicles equipped with more than one brake 
power unit or brake power assist unit, conduct 
tests for each in turn. 

57.10.2 Optional procedures— passenger cars 
only. On vehicles with brake power assist units, 
the unit is charged to maximum prior to start of 
test. (Engine may be run up in speed, then throttle 
closed quickly to attain maximum charge on 
vacuum assist units.) Brake power units shall also 
be charged to maximum accumulator pressure 
prior to start of test. No recharging is allowed 
after start of test. 

(a) (For vehicles with brake power assist units.) 
Discormect the primary source of power. Make 

six stops each from 60 mph, to achieve the aver- 
age deceleration for each stop as specified in 
Table III. Apply the brake control as quickly as 
possible. Maintain control force until vehicle has 
stopped. 

At the completion of the stops specified above, 
deplete the system of any residual brake power 
reserve capability. Make one stop from 60 mph at 
an average deceleration of not lower than 7 fpsps 
for passenger cars (equivalent stopping distance 
554 feet), or 6 fpsps for vehicles other than pas- 
senger cars (equivalent stoppng distance 646 feet) 
and determine whether the control force exceeds 
150 pounds. 

(b) (For vehicles with brake power units with 
accumulator type systems.) Test as in S7. 10.2(a), 
except make 10 stops instead of 6 and, at the 
completion of the 10 stops, deplete the failed ele- 
ment of the brake power unit of any residual 
brake power reserve capability before making the 
final stop. 

(c) (For vehicles with brake power assist or 
brake power units with backup systems.) If the 
brake power or brake power assist unit operates 



PART 571; S 105-13 



(Rev. 1/2/81) 



in conjunction with a backup system and tiie 
bacicup system is activated automatically in the 
event of a primary power failure, the backup sys- 
tem is operative during this test. Disconnect the 
primary source of power of one subsystem. Make 
15 stops, each from 60 mph, with the backup sys- 
tem activated for the failed subsystem, to achieve 
an average deceleration of 12 fpsps for each stop, 
(d) Restore systems to normal at completion of 
these tests. For vehicles equipped with more than 
one brake power assist or brake power unit, con- 
duct tests of each in turn. 

S7.11 Service brake system — first fade and 
recovery test. 

87.11.1 Baseline check stops or snubs. 

57.1 1.1.1 Vehicles with GVWR of 10,000 
pounds or less. Make three stops from 30 mph 
at 10 fpsps for each stop. Control force readings 
ma be tenninated when vehicle speed falls to 5 
mph. Average the maximum brake control force 
required for the three stops. 

57.11.1.2 Vehicles with GVWR greater than 
10,000 pounds. With transmission in neutral (or 
declutched), make three snubs from 40 to 20 mph 
at 10 fpsps for each snub. Average the maximum 
brake control force required for the three snubs. 

57.11.2 Fade stops or snubs. 

S7.1 1.2.1 Vehicles with GVWR of 10,000 
pounds or less. Make 5 stops from 60 mph at 15 

fpsps followed by 5 stops at the maximum attain- 
able deceleration between 5 and 15 fpsps for each 
stop. Establish an initial brake temperature before 
the first brake application of 130° F to 150° F. Ini- 
tial brake temperatures before brake applications 
for subsequent stops are those occurring at the dis- 
tance intervals. Attain the required deceleration 
within 1 second and, as a minimum, maintain it 
for the remainder of the stopping time. Control 
force readings may be terminated when vehicle 
speed falls to 5 mph. Leave an interval of 0.4 mile 
between the start of brake applications. Accelerate 
immediately to the initial test speed after each 
stop. Drive 1 mile at 30 mph after the last fade 
stop, and immediately follow the recovery proce- 
dure specified in S7. 11.3.1. 



S7.1 1.2.2 Vehicles with GVWR greater than 
10,000 pounds. With transmission in neutral (or 
declutched), make 10 snubs from 40 to 20 mph at 
10 fpsps for each snub. Establish an initial brake 
temperature before the first brake application of 
130°F. to 150°F. Initial brake temperatures before 
brake application for subsequent snubs are those 
occurring in the time intervals specified below. 
Attain the required deceleration within 1 s and 
maintain it for the remainder of the snubbing time. 
Leave an interval of 30 s between snubs (start of 
brake application to start of brake application). 
Accelerate immediately to the initial test speed 
after each snub. Drive for .5mi at 40 mph after the 
last snub and immediately follow the recovery 
procedure specified in S7. 11.3.2. 

S7.11.3 Recovery stops or snubs. 

57.1 1.3.1 Vehicles with GVWR of 10,000 Ibor 
less. Make five stops from 30 mph at 10 fpsps for 
each stop. Control force readings may be termi- 
nated when vehicle speed falls to 5 mph. Allow 
a braking distance interval of 1 mi. Immediately 
after each stop accelerate at maximum rate to 30 
mph and maintain that speed until making the next 
stop. Record the maximum control force for each 
stop. 

57.1 1.3.2 Vehicles with GVWR greater than 
10,000 lb. Witn transmission in neutural (or 
declutched) make five snubs from 40 to 20 mph 
at 10 fpsps for each snub. After each snub, accel- 
erate at maximum rate to 40 mph and maintain 
that speed until making the next brake application 
at a point 1.5 mi form the point of the previous 
brake application. Record the maximum control 
force for each snub. 



S7.12 Service brake 
reburnish. Repeat S7.6. 



system — second 



57.13 Service brake system— second fade 
and recovery test. Repeat S7.ll except in 
S7.11.2 run 15 fade stops or 20 snubs instead of 
10. 

57.14 Third reburnish. Repeat S7.6. 

57.15 Service brake system — fourth effective- 
ness test. Repeat S7.5. Then (for passenger cars) 
make four stops from either 95 mph if the speed 
attainable in 2 miles is 99 to (but not including) 



PART 571; S 105-14 



104 mph, or 100 mph if the speed attainable in 2 
miles is 104 mph or greater. 

57.16 Service brake system— water recovery 
test. 

57.16.1 Baseline cliecl< stop. Make three stops 
from 30 mph at 10 fpsps for each stop. Control 
force readings may be terminated when vehicle 
speed falls to 5 mph. Average the maximum brake 
control force required for the three stops. 

57.16.2 Wet bral<e recovery stops. With the 
brakes fully released at all times, drive the vehicle 
for 2 minutes at a speed of 5 mph, in any com- 
bination of forward and reverse directions, through 
a trough having a water depth of 6 inches. After 
leaving the trough, immediately accelerate at 
maximum rate to 30 mph without a brake applica- 
tion. Immediately upon reaching that speed make 
five stops, each from 30 mph at 10 fpsps for each 
stop. After each stop (except the last), accelerate 
the vehicle immediately at a maximum rate to a 
speed of 30 mph and begin the next stop. 

57.17 Spil<e stops. Make 10 successive spike 
stops from 30 mph with the transmission in neu- 
tral, with no reverse stops. Make spike stops by 
applying a control force of 200 pounds while 
recording control force versus time. Maintain con- 
trol force until vehicle has stopped. At completion 
of 10 spike stops, make 6 effectiveness stops from 
60 mph. 

57.18 Final Inspection. Inspect — 

(a) The service brake system for detachment or 
fracture of any components, such as brake springs 
and brake shoes or disc pad facing. 

(b) The friction surface of the brake, the master 
cylinder or brake power unit reservoir cover, and 



seal and filler openings, for leakage of brake fluid 
or lubricant. 

(c) The master cylinder or brake power unit 
reservoir for compliance with the volume and 
labeling requirements of S5.4.2 and S5.4.3. In 
determining the fully applied worn condition 
assume that the lining is worn to (1) rivet or bolt 
heads on riveted or bolted linings or (2) within 
'/32 inch of shoe or pad mounting surface or 
bonded linings, or (3) the limit recommended by 
the manufacturer, whichever is larger relative to 
the total possible shoe or pad movement. Drums 
or rotors are assumed to be at nominal design 
drum diameter or rotor thickness. Linings are 
assumed adjusted for normal operating clearance 
in the released position. 

(d) The brake system indicator light(s), for 
compliance with operation in various key posi- 
tions, lens color, labeling, and location, in accord- 
ance with S5.3. 



S7.19 Moving barrier test. (Only for vehicles 
that have been tested according to S7.7.2.) Load 
the vehicle to GVWR, release parking brake and 
place the transmission selector control to engage 
the parking mechanism. With a moving barrier as 
described in paragraph 3.3 of SAE Recommended 
Practice J972 "Moving Barrier Collision Tests," 
November 1966, impact the vehicle from the front 
at 272 mph. Keep the longitudinal axis of the bar- 
rier parallel with the longitudinal axis of the 
vehicle. Repeat the test, impacting the vehicle 
from the rear. 

Note: The vehicle used for this test need not he 
the same vehicle that has been used for the brak- 
ing tests. 



PART 571; S 105-15 



EffKllv*: September 1, 1974 



PREAMBLE TO AMENDMENT TO MOTOR VEHICLE SAFETY STANDARD NO. 106 

Brake Hoses 
(Docket No. 1-5; Notice 8) 



This notice amends 49 CFR 571.106, Motor 
Vehicle Safety Standard 106, Hydraulic Brake 
Hoses, by (1) extending its requirements to all 
motor vehicles and hydraulic, air, and vacuum 
brake hose, brake hose assemblies, and brake 
hose end fittings for use in those vehicles, (2) 
replacing some design-oriented requirements with 
performance requirements for brake hose, brake 
hose assemblies, and brake hose end fittings, and 
(3) establishing comprehensive labeling require- 
ments for brake hose, brake hose assemblies, and 
brake hose end fittings. 

A notice of proposed rulemaking on this sub- 
ject was published on March 30, 1971 (36 F.R. 
5855). It revised and corrected earlier proposed 
amendments and proporsd the elimination of 
many design specifications in favor of broad 
performance requirements. This reorientation 
generated little comment, but extensive comments 
were received on the details of the proposed 
requirements. 

Tests conducted by the NHTSA Safety Sys- 
tems Laboratory and comments to the docket 
both indicated that the extensive sequential test- 
ing proposed in the NPRM could be an unpre- 
dictable measure of brake hose performance and 
much sequential testing was eliminated. One of 
the remaining sequential tests requires that all 
hose assemblies meet the constriction test as well 
as any other single test. 

Several comments indicated confusion con- 
cerning the rule's applicability to components of 
the brake system. The definition of brake hose 
now limits the standard to flexible conduits that 
transmit or contain the fluid pressure or vacuum 
used to apply force to a vehicle's brakes. This 
excludes such hose as that from the brake fluid 
reservoir to the master cylinder, and that from 



the air compressor discharge to its reservoir. 
Chassis plumbing which is flexible falls within 
the definition of brake hose, as does hose from 
the engine to the vacuum booster. 

In response to continued requests for physical 
tolerances and related accommodations for test- 
ing, it is reiterated that the safety standards 
should in all cases be considered as performance 
levels that each vehicle or item of equipment 
must meet, and not as instructions for manu- 
facturer testing. Thus, a 35-hour continuous 
flex test .procedure sets the minimum perform- 
ance level that the hose must meet when the 
NHTSA tests for compliance. The manufacturer 
may certify this performance level on the basis 
of interrupted tests as long as, in the exercise of 
due care, these tests provide assurance that his 
hose complies and will withstand 35 hours of 
continuous flexing. In response to another ques- 
tion, the manufacturer must determine for him- 
self how frequently he should test his products 
to ensure that they comply. 

The standard does not establish varying burst 
strength requirements for different size hose, 
because all sizes may be subject to extreme pres- 
sure conditions. Neither does the standard re- 
move wire-braided air brake hose from the 
adhesion requirements as requested, because the 
NHTSA has concluded that properly embedded 
wire-braided hose will sustain an 8-pound pull, 
and that no sufficient data exists to exempt wire- 
braided hose at this time. 

Labeling requirements have been modified in 
response to comments to permit (1) lettering to 
fit smaller size hoses, (2) antitorque stripes that 
are "clearly identifiable" in order to accommo- 
date a molding process as well as color-striping, 
(3) use of fractions to express the hose inside 



PART 571; S 106— PRE 1 



EffMHva: S*pt«mb*r I, 1974 

diameter, and (4) interruption of the second 
stripe with optional additional information not 
permitted in the legend that interrupts the first 
stripe. In this way, the labeling provision re- 
quires certain safety-related information ex- 
pressed in a specified format, and it also permits 
labeling with additional information by the 
manufacturer at his option. For example, sev- 
eral comments suggested the use of "air-brake" 
in lieu of "A" and inclusion of SAE air brake- 
hose type designations as, a part of labeling air 
brake components. Another comment requested 
metric labeling. As modified, the standard now 
permits all this information to be placed on the 
hose as additional information. 

Labeling requirements for brake hose end fit- 
ting manufacturers no longer include the as- 
sembly completion date. Instead, the assembler 
is required to place a band on each hose assembly 
which indicates the assembly completion date. 
"Brake hose assembly" has been redefined to ex- 
clude assemblies containing used components, 
and this effectively excludes repair operations 
from the requirements of the standard. 

The amendment has been reorganized to 
clearly indicate that it applies to three types of 
hose, hose assemblies, and end fittings. The re- 
quirements and test procedures for each type of 
hose have been grouped together for clarity, in 
response to docket comments. 

Changes to the hydraulic brake hose require- 
ments include revision of many sequential tests. 
The 1,500 psi air pressure resistance test was 
eliminated as an inappropriate measure of hy- 
draulic brake hose performance. The water 
absorption test proposed in the NPRM was di- 
vided into three distinct tests. The test tem- 
perature in the brake fluid compatibility test 
has been lowered to more accurately reflect ve- 
hicle operating conditions and to approach a 
more suitable test temperature for the specified 
procedure. 

Few changes were made to the vacuum brake 
hose section. In response to the request of its 
manufacturers, %2-inch hose has been added to 
the performance requirements data. Distinctions 
between light and heavy duty hose were largely 
eliminated. 



All sequential testing except for the constric- 
tion test and one water absorption-tensile 
strength test has been eliminated from the air 
brake hose requirements. Comments indicated 
that the extensive combination of tests was in- 
appropriate to measure the adequacy of tradi- 
tionally constructed air brake hose. The 
ultraviolet test has been eliminated until suf- 
ficient data is generated to support a minimum 
performance requirement. The standard has 
also been modified to allow use of permanent as 
well as reusable end fittings. As anticipated in 
the NPRM, outside and inside diameter specifi- 
cations have been added to the requirements for 
two types of air brake hose, although these 
specifications do not require the use of Standard 
SAE 100R5 fittings as proposed in the NPRM, 

The suggested standardization on 100R5 fit- 
tings generated the greatest number of comments 
on the rulemaking. Comments generally agreed 
that thread engagement and component attach- 
ment should be standardized. However, dis- 
agreement exists on which fitting is most suitable 
for standardization. Many comments indicated 
that type E fittings are predominant in the in- 
dustry and will be more so in the future and that 
their non-proprietary design permits manufac- 
ture by anyone. The NHTSA has decided, on 
the basis of the comments received, not to stand- 
ardize on any type of fitting at this time. This 
amendment only establishes hose diameters and 
tolerances intended for use in reusable air brake 
hose assemblies as a first step toward standardi- 
zation of the air brake hose assembly. Notice 
and further opportunity to comment will pre- 
cede any rulemaking on the standardization of 
air brake hose assemblies. 

In consideration of the foregoing. Standard 
No. 106, Brake Rosea, 49 CFR Part 571.106, is 
amended to read as set forth below. 

Effective date : September 1, 1974, 

(Sec, 103, 119, Pub. L. 89-563, 80 Stat. 718, 
15 U.S.C. 1392, 1407; delegation of authority at 
49 CFR 1.51.) 

Issued on November 5, 1973. 

James B. Gregory 
Administrator 

38 F.R. 31302 
November 13, 1973 



PART 571; S 106— PRE 2 



Effective: January 29, 1974 



PREAMBLE TO AMENDMENT TO MOTOR VEHICLE SAFETY STANDARD NO. 106 

Brake Hoses 
(Docket No. 1-5; Notice 9) 



This notice amends Standard No. 106, Brake 
hoses, 49 CFR 571.106, to require a manufacturer 
designation in place of the manufacturer identifi- 
cation code assigned by the National Plighway 
Traffic Safety Administration (NHTSA) which 
is presently required by the labeling provision. 

The NHTSA has not completed consideration 
of comments to its manufacturer's identification 
code proposal published June 7, 1973 (38 F.R. 
14968). General Motors has stated that produc- 
tion of 1975 model vehicles that conform to 
Standard 106 will require the immediate manu- 
facture of brake hose that conforms to Standard 
106. This amendment modifies the identification 
i«quirements to permit the use of manufacturer 
designations, such as those presently in use, until 
the NHTSA issues a final rule on the manufac- 
turer's identification code proposal. At that time 
the standard would be amended again to require 
whatever code might be assigned by the NHTSA. 

Other matters raised by petitions for recon- 
sideration are presently under consideration and 



will be answered in accordance with the proce- 
dures of 49 CFR 553.35, Petitions for recon- 
sideration. 

In consideration of the foregoing. Standard 106 
(49 CFR 571.106) is amended .... 

Effective date: January 29, 1974. Because this 
amendment creates no additional burden, and be- 
cause of the immediate need for an effective re- 
quirement applicable to equipment to be produced 
for the 1975 model year, it is found for good 
cause shown that notice and public procedure 
thereon are impracticable, and that an immediate 
effective date is in the public interest. 

(Sees. 103, 119, Pub. L. 89-563, 80 Stat. 718, 
15 U.S.C. 1392, 1407; delegation of authority at 
49 CFR 1.51.) 

Issued on January 23, 1974. 

James B. Gregory 
Administrator 

39 F.R. 3680 
January 29, 1974 



PART 571; S 106— PRE 3^ 



Effective: September 1, 1974 
January 1, 1975 



PREAMBLE TO AMENDMENT TO MOTOR VEHICLE SAFETY STANDARD NO. 106-74 

Brake Hoses 
(Docket No. 1-5; Notice 10) 



This notice responds to petitions for recon- 
sideration of amended Standard 106, Brake hoses, 
49 CFR 571.106, published November 13, 1973 
(38 F.R. 31302). In response to comments by 
36 manufacturers and users of brake hoses, tlie 
National Highway Traffic Safety Administration 
(NHTSA) amends the definitions, labeling, and 
performance provisions of the standard in several 
respects. 

The Motor Vehicle Manufacturers Association, 
the American Trucking Association, and three 
manufacturers questioned the applicability of the 
standard to nylon and thermoplastic tubing used 
in the chassis plumbing of air brake systems. 
They asserted that Notice 7 offered no opportunity 
for comment on the properties and use of this 
material and that no safety need could justify 
its inclusion in the standard. The comments 
point to a distinction in industry terminology be- 
tween "tubing" and "hose" to argue that NHTSA 
use of the term "hose" limited the proposal to 
traditional applications of six SAE hose types 
at articulating points in the air brake system. 

The NHTSA considers that the broad defini- 
tion of "Airbrake hose" provided an opportunity 
to comment on the issue of tubing. Notice 7 de- 
fined "Airbrake hose" as "a flexible hose for use 
in an airbrake system . . ." and it clarified this 
definition in the preamble to the notice. 

Major revisions have been made in the air- 
brake hose portion of the proposal by elim- 
inating the six types previously specified. 
Thus an airbrake hose under the proposal may 
be manufactured from any material as long as 
the hose can meet the performance require- 
ments of the standard. 

The NHTSA included "flexible" in its definition 
of hose, despite the common meaning of hose as 



flexible pipe or tubing, to emphasize the exclusion 
of relatively inflexible elements of an airbrake 
system such as copper tubing commonly found in 
chassis tubing. Finally, the broad term "air 
brake system" adequately gives notice of the 
standard's applicability to the chassis plumbing 
portion of that system. The NHTSA deter- 
mined that a safety need exists to include flexible 
chassis plumbing in this standard because it is 
used in the same environment as hose located at 
articulating points and is subject to many of the 
same types of stress, including heat, cold, and 
pressure. A failure of either flexible conduit 
creates as great a safety hazard. For these rea- 
sons, the petitions that tubing be excluded from 
the standard are denied. 

Manufacturers who commented on the use of 
nylon and thermoplastic in air brake systems ex- 
pressed confidence that their products, which are 
in widespread use as chassis plumbing, will meet 
the requirements of the standard. They re- 
quested testing to exclude inadequate materials 
which might also meet the present requirements. 
The NHTSA expects to propose additional re- 
quirements after review and testing demonstrate 
that traditional hose materials presently in use 
will not be excluded arbitrarily. In the interim, 
the NHTSA's safety defect authority can pre- 
vent the use of inadequate materials. 

To accommodate the inclusion of nylon and 
thermoplastic, the comments also requested a 
revision of the tensile strength value for the 
smaller nylon and thermoplastic hose. This 
change has been made. It should be stressed 
that the applicability of this standard to nylon 
and thermoplastic tubing does not affect tubing 
construction or characteristics. 



PART 571; S 106— PRE 5 



Effective: September 1, 1974 
January 1, 1975 



"Brake hose" is defined in the final rule as "a 
flexible conduit that transmits or contains the 
fluid pressure or vacuum used to apply force to 
a vehicle's brakes." Wagner Electric and several 
other manufacturers argued that a definition like 
this which differs from accepted industry term- 
inology should include a list of the parts of the 
brake system it covers. Actually, the use of 
general language different from industry term- 
inology is specifically intended to avoid identifica- 
tion with specific designs and thereby permit 
the definition to accommodate future designs as 
they develop. The preamble refers to specific 
lines only in response to manufacturer requests 
for interpretations, and the NHTSA will con- 
tinue to provide interpretations to interested 
persons upon request. The NHTSA interprets 
the term "flexible" to exclude copper or steel 
tubing. In response to Chrysler, General Motors, 
Ford, and Mercedes-Benz, the NHTSA reiterates 
that the vacuum and hydraulic booster lines that 
service power brake systems transmit or contain 
pressure used to apply force to a vehicle's brakes 
within the meaning of the definition. Accessory 
air lines such as those to the power air horn and 
windshield wipers are, of course, excluded. 

The definition of "brake hose assembly" in the 
rule covered both combinations of clamps and 
hose and combinations of end fittings and hose. 
The NHTSA has deleted reference to clamps, in 
agreement with manufacturers who pointed out 
that the mounting of a slip-on clamp and hose is 
an essentially different manufacturing operation 
that, if regulated, should be subject to different 
performance requirements from brake hose as- 
semblies. The clamp assemblies are subject to 
NHTSA safety defect authority. Comments dis- 
agreed for various reasons on the exclusion of 
hose assemblies containing used components from 
the standard. The NHTSA concludes that the 
exclusion is realistic and justified. 

The standard now defines "permanently at- 
tached end fittings" to make clear that 3-piece 
hose fittings which utilize sacrificial sleeves or 
ferrules are permanently attached end fittings 
and that the hose used with them is not pro- 
hibited by S7.1. In addition to the action taken 
with respect to the definition, %-in and V2-in 
hose sizes have been added to Table III under 



both Type I and Type II hose in order that their 
use may be continued. 

The definition of "rupture" has been modified 
slightly to make clear that the two types of 
failure included in the definition are "separation 
of the hose from its end fitting" and "leakage". 
Both a small leak and a hose burst constitute 
"leakage" under this definition. 

Manufacturers of brake hose assemblies and 
vehicles petitioned for numerous \^ariations in 
the labeling provisions. The many proposed 
changes in brake hose assembly labeling illustrate 
the importance of uniform labeling in a field 
where differing combinations of responsibility 
exist between manufacturers and installers of 
hose assembly components. 

The NHTSA has determined that the basic 
assembly banding technique set forth in Notice 
8 remains the clearest uniform identification 
method for assembly manufacturers. The band 
may be freely attached at any point on the as- 
sembly to minimize binding and wear as long as 
it is retained by the end fittings. An exception 
to the banding requirement has been made for the 
vehicle manufacturer who assembles and installs 
his own brake hose assemblies, because his assem- 
blies are integrally related to the vehicle, and the 
vehicle certification and identification informa- 
tion serves to identify and certify the hose as- 
sembly. The manufacturer may choose to band 
those hose assemblies subject to being rebuilt, to 
delimit his responsibiilty in the event a rebuilt 
assembly fails. 

Manufacturers will be permitted to mark the 
date of manufacture by day or month on the 
assembly and hose. The identification code re- 
quired on each component is not yet available for 
issuance and therefore an amendment of the 
standard has already been issued to permit use 
of a manufacturer designation in place of the 
code (39 F.R. 3680, January 29, 1974). That 
language has been revised to allow the use of a 
manufacturer designation that does not consist of 
the block capital letters otherwise required by 
S5.2.2, S5.2.3, and S5.2.4. 

The labeling requirements now reflect the use 
of nominal inside and outside diameter desig- 
nations. The hose labeling has been modified 
from "not less than 6 inches" to "not more than 



PART 571; S 106— PRE 6 



Effective: September 1 , 1 974 
January 1, )975 



6 inches" in response to many requests. Toyotii's 
request for one-stripe labeling of required and 
optional information has been denied, to ensure 
that the required information appears at least 
once on hose as short as 4 inciies. The NUTS A 
has denied requests for rearrangements of tlie 
required information, conchiding that tliey would 
not make it clearer to the user. In response to 
Midland-Ross' request for clarification, it is re- 
iterated that, while the NHTSA requires certain 
safety-related information expressed in a certain 
format, it does not prohibit the addition of other 
information elsewhere on hydraulic, air, or 
vacuum hose. 

Several manufacturers of hydraulic brake hose 
assemblies argued that end-fitting labeling in- 
formation becomes meaningless once a fitting is 
permanently attaclied to a hose. They reasoned 
that the crimping process deforms the fitting, its 
coating, and possibly the lettering, so that no 
fitting manufacturer would certify his prodiict 
to the assembler, and that the responsibility for 
the fitting's conformity would in any case fall 
on the assembler. 

While the NHTSA expects the labeling in- 
formation to serve a useful purpose on reusable 
and 3-piece permanently attached end fittings, 
the limited benefit of markings on a crimped 
fitting justifies their elimination. In fact the 
one performance requirement that applies to fit- 
tings has been modified to reflect the crimping 
process and it effectively becomes the assembler's 
responsibility to meet this corrosion resistance 
provision. 

There were several general comments on the 
performance requirements and the test proce- 
dures. There were requests for physical toler- 
ances, especially for the expansion test apparatus, 
and related accommodations for test purposes. 
These arise from misunderstanding of the legal 
nature of the safety standards, which are per- 
formance levels that each vehicle or item of motor 
vehicle equipment must meet, and not instructions 
for manufacturer testing. In the case of a cali- 
bration factor, for example, the NHTSA set an 
exact performance level by stating its require- 
ment without a tolerance. Then, in compliance 
testing, it determines the calibration factor of 
its equipment and gives the benefit of that factor 
to the manufacturer in assessing the test results. 



(correspondingly, the manufacturer should deal 
with an exact performance le\el by determining 
the calibration factor of his equipment and pe- 
nalizing his test results by that amount. Manu- 
facturer testing should be directed at proving the 
equipment's capability in the exercise of due care, 
by testing under conditions at least as adverse 
as any that could be established in accordance 
with the procedures. For example, to accept 
Goodyear's suggested room temperature range 
of 65° to 90°F. would permit the NHTSA to 
test at any temperature within the range, and a 
manufixcturer would correspondingly have to test 
to assure himself that his product would conform 
at every point within the range. 

Toyota expressed some confusion about sequen- 
tial testing. As stated in S5.3, S7.3, and S9.2, a 
particular hose, end fitting, or hose assembly 
need not meet further requirements after having 
met the constriction requirements and any one 
other requirement listed. A particular hose as- 
sembly, therefore, would have to meet the con- 
striction requirement in each case and then one 
other selected requirement, of which S5.3.6. Wafer 
absorption and tensile strength, is one example. 

The constriction requirement requires that any 
cross section which the NHTSA chooses to ex- 
amine will be a certain percentage of the nominal 
diameter. Again the manufacturer may utilize 
whatever test method convinces him in the exer- 
cise of due care that his i)roduct conforms to the 
constriction requirement. Chrysler objected to 
the application of the constriction test to hose 
assemblies, citing situations where restrictions 
are designed into brake systems for pressure con- 
trol. The NHTSA has determined that the estab- 
lished percentages limit constrictions to a safe 
level. 

With regard to the requirements as a group, 
it is noted that, while a hose must conform to 
any of the requirements, it need not be tested 
to requirements that are obviously inapplicable. 
For instance, thermoplastic tubing need not be 
subjected to the adhesion test because it is ob- 
vious that there are no layers in this constric- 
tion which could fail to adhere. 

Numerous comments were addressed to specific 
hydraulic performance requirements. The expan- 
sion and burst-strength requirements included a 



PART 571 ; S 106— PRE 7 



Effective: September t, 1974 
January 1, 1975 

30-minute waitinp; period, which has been elim- 
inated as unnecessary. The procedure is modified 
to better describe the test sequence, and two 
values in Table I are corrected. 

With regard to mounting hose assemblies hav- 
ing L-shnped end fittings in a flexing macliine. 
the te'-'. procedures liave been modified to permit 
the use of adapters to secure the assembly to the 
machine with the same orientation as a straight 
assembly. 

The low-temperature resistance test for hy- 
draulic hose has been modified from — f)5°F. 
to — 40°F. in line with air and vacimm hose test 
values. 

A hydraulic hose assembler objected that use 
of SAE RM-1 compatibility fluid liad not been 
proposed in Notice 7 and therefore could not be 
specified in the final rule. Notice 7 proposed use 
of "brake fluid conforming to Standard No. 116." 
This means that the NHTSA could ha\e cliosen 
any such fluid for use in its tests, and that the 
manufacturer would have to test with each fluid 
or otherwise assure himself in the exercise of 
due care that his hose assembly could meet the 
requirements using eacli fluid conforming to 
Standard No. 116. Specification of a single fluid 
is therefore a relaxation of the proposed require- 
ment. The Society of Automotive Engineers 
Referee Materials Subcommittee, which contracts 
for production of RM-1 fluid, has assured the 
NHTSA of its continued availability for at least 
the next 3 years. A modification of the require- 
ments has been made for mineral -type systems. 

The NHTSA agrees with Wagner Electric 
that the end fitting corrosion requirement must 
accommodate the crimping and labeling process, 
and the requirement is amended to permit dis- 
placement of the protective coating necessary to 
mark the fittings and attach it to a hose. 

Several comments were addressed to the air 
brake hose requirements. Clarifying language 
has been added to make clear that air brake hose 
assemblies may be constructed with permanent 
or reusable end fittings. Table III now includes 
A- and B-type hose in %- and V2"ii^ special 
diameters to assure its continued availability, 
particularly for replacement purposes. The con- 
striction test value of 66 percent remains un- 
changed because the calculation method is 



already consistent with hydraulic value of 64 
percent. 

Table IV is revised to include outside dimen- 
sions. New, smaller radii for tubing tests can- 
not be adopted, however, until there has be«n 
notice and opportunity to comment. In answer 
to Toyota's request for interpretation, it is cor- 
rect that the test cylinder radii are directly pro- 
portional to the diameter of the ho.se being tested. 
Suggestions to examine the inner as well as 
outer layers of hose subjected to the low-tem- 
perature resistance test will be considered in 
future rulemaking, since interested persons 
should be given notice and opportunity to com- 
ment. The same considerations apply to Samuel 
Moore Company's suggested higher test tempera- 
ture in the oil-resistance requirement, more 
demanding percentages in the length change 
requirement and the high-temperature burst 
strength test. The oil resistance test specimen 
has been modified to one-third of an inch in 
width because i/^-in specimens can not be cut 
from the smaller hose sizes. The burst strength 
value is reduced to 800 psi to accommodate nylon 
and thermoplastic tubing while retaining a safety 
performance level five times that of normal 
operating conditions. 

The application of air pressure has been re- 
tained in the length change test and the air 
pressure test, despite requests for "optional" pres- 
sure sources. Hidden options of tliis type are 
generally undesirable in the safety standards, 
since they make uncertain the level of required 
performance, and complicate the comparison of 
manufacturer and NHTSA test results. The 
manufacturer is free to use pressure sources other 
than air as long as his results assure him that 
the hose would meet the requirement if air were 
used. 

Manufacturers proposed alternative means of 
testing the adhesion of hose layers because of the 
difficulty associated with testing wire-braided 
and small diameter hose. As pointed out in the 
petitions, sufficient care in conducting the present 
test will prevent these difficulties. Any manu- 
facturer who believes that the alternative pro- 
cedure has significant advantages should submit 
a petition for rulemaking with supporting data. 



PART 571; S 106— PRE 8 



Some comments on the adliesion test argued 
for the averaging of test residts witliout specify- 
ing any objection to the present procedure. At 
this time, it does not appear that averaging 
would be desirable for purposes of this standard. 
In another area, some tensile strength test values 
have been reduced in recognition of the use of 
tubing in nonarticulating applications. The dis- 
tinction betwfeen permanent and reusable fittings 
is eliminated, consistent with the rationale that 
the components may operate under the same con- 
ditions. 

The NHTSA denies Wagner Electric's re- 
quested re-establishment of the air pressure test 
procedures which appeared in Notice 7. These 
procedures were modified because comments ob- 
jected to the measuring technique. As noted 
previously, the manufacturer may use any test 
method which assures him the equipment meets 
the requirement as stated. 

One significant question was raised with regard 
to the vacuum hose requirements. Table V in- 
advertently listed the- same hose lengths and 
cylinder radii for the low and high temperature 
resistance tests. A new column of values is 
added to that table. 

Because of the additional leadtime required 
to purchase conforming brake hose and assemblies 
for use in vehicles which must conform to the 
standard, the effective date of the standard as it 
applies to vehicles is delayed 4 months to Jan- 



Effective: September 1, 1974 
January 1, 1975 

uary 1, 1975. An amendment to the presently 
effective Standard lOfi permits compliance either 
with that standard or with this standard, as it 
is effective September 1, 1974. 

Interested persons are reminded that, in addi- 
tion to the amendments set forth below, an amend- 
ment of Standard lOG has already been issued 
which permits the use of a manufacturer desig- 
nation in place of the identification code called 
for in the rule as first issued. (.".9 F.R. .3680, 
January 29, 1974.) 

In consideration of the foregoing, both Stand- 
ard No. 106, 49 CFR .571.106, in its presently 
effective form and Standard No. 106 as it is effec- 
tive September 1, 1974, and January 1, 1975, are 
amended. 

The present Standard No. 106 is amended by 
the addition of a new paragraph .... 

Effective dates: September 1, 1974, for equip- 
ment covered by the standard; January 1, 1975, 
for vehicles to which the standard applies. 

(Sees. 103, 119, Pub. L. 89-563, 80 Stat. 718, 
15 U.S.C. 1392, 1407; delegation of authority at 
49 CFR 1.51.) 

Issued on February 20, 1974. 

James B. Gregory 
Administrator 

39 F.R. 7425 
FebruaiY 26, 1974 



PART 571; S 106— PRE 9-10 



Efftcllv*: Saplambtr 1, 1974 
March 1, 1975 
September 1, 1975 



PREAMBLE TO AMENDMENT TO MOTOR VEHICLE SAFETY STANDARD NO. 106-74 

Brake Hoses 
(Docket No. 1-5; Notice 11) 



This notice amends Standard No. 106, Brake 
hoses, 49 CFR 571.106, by modifyinj^; the defini- 
tion of "permanently attached end fitting", the 
effective date for brake hose assemblies and ve- 
hicles, several labeling requirements, and certain 
tensile strength, constriction, and corrosion re- 
sistance requirements, in response to petitions for 
reconsideration of amendments published Jan- 
uary 29, 1974 (39 FR. 3680) (Notice 9) and 
February 26, 1974 (39 FR 7425) (Notice 10). 
In addition, Toyo Kogyo Company, in a letter 
request for interpretation, pointed out an in- 
advertent change of language in Notice 8 (38 FR 
31302, November 13, 1973) which is corrected in 
this notice. 

Notice 9 

Notice 9 amended the standard to permit the 
use of "a designation that identifies the manufac- 
turer" of an end fitting, hose or hose assembly 
in place of a manufacturer identification code 
which the NHTSA is not yet prepared to issue. 
Any designation which is filed with the NHTSA 
may be used until the permanent code is imple- 
mented. The only comment on Notice 9 was 
made by Weatherhead Company, which objected 
to any interim marking on grounds of expense 
and advocated elimination of all label identifica- 
tion from' the hose. The NHTSA considers iden- 
tification other than a colored thread to be 
reasonable and necessary for rapid recognition, 
and Weatherhead 's first petition is denied. 

Although not raised by Weatherhead in its 
petition, several assemblers have objected that the 
manufacturer designation requirement conflicts 
with the general industry practice of marking 
hose with the distributor's designation. The 
NHTSA requirement that the manufacturer des- 
ignation appear on one side of the hose in the 



required format does not in any way prevent 
labeling of hose with the distributor's designa- 
tion on the opposite side of the hose along with 
other optional information. 

Weatherhead petitioned for revision of the 
identification requirements to permit designations 
other than block capital letters and numerals. 
The necessary language has already been added 
to the standard in Notice 10. 

Weatherhead also requested a modification of 
the definition of "end fitting" that would exclude 
end fitting components from the labeling require- 
ments in order to accommodate the practice of 
assembler intermixing of components made by 
different manufacturers. Such an exclusion of 
components, combined with the present exclusion 
of labeling crimped-on fittings, would eliminate 
all identification requirements for all fittings. 
While unlabeled crimped fittings may be traced 
through the hose assembler's band, "renewable" 
or reuseable fittings must be labeled at least once 
to permit location of any defective fitting which 
was attached to new hose and then reused after 
it passed out of the control of the assembler and 
the NHTSA. Although the NHTSA does not 
find labeling of each part of a fitting to be fea- 
sible, it does not consider it unduly burdensome 
for an assembler to ensure that the newly as- 
sembled fitting is composed entirely of parts 
made by the manufacturer whose designation 
appears on one part. This also responds to Inter- 
national Harvester's request for interpretation on 
labeling multi-piece fittings. 

Notice 10 

Notice 10 amended the standard in response to 
petitions for reconsideration of the regulation as 
it had been issued in final form November 13, 



PART 571; S 106— PRE 11 



Effective: September 1, 1974 
Morch 1, 1975 
September 1, 1975 

1973 (38 FR 31302). The twelve petitions for 
reconsideration of tliis notice emphasized con- 
fusion over the status of hose, fittings, and as- 
semblies manufactured before the effective date, 
and disagreement with certain labeling require- 
ments and the applicability of the standard to 
particular hose types and applications. 

The use of hose and fittings manufactured 
before the September 1, 1974, effective data raises 
two problems. The most difficult of these prob- 
lems is that the components may not conform to 
any or all of the performance requirements of 
Standard 106, and therefore could not be made 
into assemblies or vehicles after the appropriate 
effective date. To alleviate this "existing stock" 
problem, Notice 10 delayed the effective date of 
the standard for vehicles 4 months to permit the 
utilization of non-106 components. This did not 
solve the problem, however, as pointed out by 
Ford and by White Motor Corporation, because 
the hose and fittings made immediately before 
the effective date must be made into assemblies 
after the effective date before they can be used 
in vehicles. This notice therefore delays the 
effective date of the standard for six months as 
it applies to assemblies. The March 1, 1975, date 
is set with reference to materials submitted by 
vehicle and hose and fitting manufacturers that 
support a delay somewhat longer than 4 months 
to absorb existing stocks. Because it will take 
some months to stock inventories with conform- 
ing assemblies after March 1, 1975, the effec- 
tive date of the standard for vehicles is delayed 
until September 1, 1975. 

The delay in effective date for assemblies and 
vehicles will minimize difficulties in the transition 
to hose marked witli the DOT symbol. This 
transition problem arises because of the require- 
ment that the DOT appear on conforming hose, 
fittings, and assemblies, but that it not appear 
on hose to which no safety standard applies, that 
is, hose manufactured before the standard's effec- 
tive date. This principle has been consistently 
followed in the labeling of tires and other items 
of motor vehicle equipment to avoid confusion 
in the meaning of the symbol and the concept of 
compliance. The problem does not arise in the 
labeling of hydraulic hose for use in passenger 
cars because a standard already applies and the 



DOT symbol can be used to indicate compliance 
with it. 

The difficulty in labeling brake hose with the 
DOT symbol is not that of a September 1, 1974. 
"midnight changeover". The problem is that any 
hose assemblies used in new vehicles iliust con- 
form to the standard as of the effective date for 
vehicles. With the present change, the hose and 
fittings used as original equipment must bear the 
DOT symbol as of September 1, 1975. The new 
effective dates provide six months to absorb pre- 
standard stock in assemblies and then six more 
months to prepare conforming assemblies for 
use in 1976 model vehicles. What stock remains 
can, of course, be sold in the replacement market. 

The greatest number of petitions concerned the 
applicability of the standard to specific hose 
types and applications in the vehicle. Three 
petitions again sought the exclusion of plastic 
tubing from the standard, stating reasons which 
have already been responded to in detail in the 
preamble to Notice 10. The major concern in 
this area appears to be whether specific tubing 
assemblies are subject to the high tensile strength 
tests for "relative motion"'. This term has raised 
numerous requests for interpretation, and to 
make clearer the tensile strength distinction, 
"relative motion" has been replaced with more 
specific wording. The new language specifies 
that hose assemblies (other than coiled nylon 
tube assemblies which meet the requirements of 
BMCS Regulations (49 CFR §393.45)) used be- 
tween chassis and axles or between towing and 
towed vehicles must meet the higher tensile 
strength requirements. 

The American Trucking Association (ATA) 
mistakenly concluded that the signal line between 
tractor and trailer was totally excluded from the 
standard, and also the line to any reservoir and 
to the spring brakes. All these lines fall within 
the definition of brake hose because the signal 
pressure, the pressure to the reservoir, and the 
pressure to the spring brake chamber in each 
case is "used to apply force to tlie brakes''. This 
wording should not be misread as restricted to 
pressure directly used to apply the brakes. 

The definition of brake hose has been reworded 
to avoid a problem in another area. As presently 
worded only hose actually used in the brake sys- 



PART 571; S 106— PRE 12 



tem would qualify as brake hose and be entitled 
to be labeled with the DOT symbol. The re- 
wording permits hose '"manufactured for use in 
a brake system" to be labeled with the DOT 
symbol even if it is used, for example, as a 
supply line to the windshield wiper system. 

Weatherhead requested further definition of the 
term "flexible" as it is used in the definition of 
brake hose. The NHTSA continues to believe 
that this concept can best be treated on a case- 
by-case request for interpretation and, as noted 
in Notice 10, will continue to make interpreta- 
tions upon request. 

Chrysler petitioned for a change in the word- 
ing of the definition of "brake hose", apparently 
directed toward the exclusion of the hydraulic 
brake booster assembly from the standard. Ford, 
General Motors, and the Motor Vehicle Manufac- 
turers A.si=ociation (MVMA) also petitioned to 
exclude the hydraulic booster lines on the grounds 
that they are subject to a different working en- 
vironment than brake hose. The most important 
difference is the constant flow of fluid through 
them, requiring a long, complicated, tuned, and 
expandable hose. The NHTSA has concluded 
that the difference in requirements for the hy- 
draulic booster system justifies special perform- 
ance requirements for this application. Until 
these requirements are developed, hydraulic 
brake booster hose running from pump to ac- 
cumulator will be considered to be exempt from 
the requirements of this standard. Hose running 
from accumulator to booster will also be exempted 
if redundant booster is provided. This exemp- 
tion applies to hoses for which Rolls Royce 
petitioned for exemptions from certain test re- 
quirements. 

White Motor Corporation petitioned to include 
"the chassis portion" in the definition of brake 
hose assembly, incorrectly assuming that the dis- 
cussion of chassis plumbing in the preamble to 
Notice 10 limited the definition to brake line 
mounted to the frame at one point. Chassis 
plumbing was emphasized in Notice 10 only be- 
cause inclusion of that part of the brake system 
in the standard had been questioned by several 
petitioners. In answer to White, Standard No. 
106 is not limited to hose "installed on the chassis 
to the point of the last mechanical connection", 



Effaelive: September 1, 1974 
March 1, 1975 
September I, 1975 

but includes any hose equipped with end fittings 
for use in a brake system. 

The ATA expressed dissatisfaction at the 
applicability of hose assembly requirements to 
assemblies made in the field from all-new com- 
ponents. The NHTSA has accommodated emer- 
gency repairs by excluding hose assemblies which 
contain used components, whether renewable or 
reusable. There is no reason, however, to rou- 
tinely exempt the smaller assemblers from the 
requirements of the standard simply because 
past practices have permitted fabrication of as- 
semblies in the field by anyone who has the 
necessary equipment. In this regard, the NHTSA 
believes the practice of refabrication of hose 
assemblies in the correct length in the field for 
emergency repairs promotes safety, by not forcing 
substitution of a permanent assembly which is 
only a "close fit". For this reason Weatherhead's 
petition to require permanent fittings on all brake 
hose is denied. 

Several questions were raised with regard to 
end fittings. Most important to manufacturers 
is elimination of the reference to two- and three- 
piece end fittings in the definition of permanently 
attached end fittings. This definition, as well as 
the reference in S5.2.3, has been changed to 
eliminate this design restriction. 

The status of intake manifold connectors and 
booster check valves typically clamped to the ends 
of vacuum booster hose were also questioned. 
"Brake hose end fitting" is defined as "a coupler, 
other than a clamp, designed for attachment to 
the end of a brake hose." As typically configured, 
the couplers are the clamps, and the intake mani- 
fold connection and brake booster check valve 
are engine components to which the brake hose 
has been attached by the clamp couplers. There- 
fore neither component is subject to Standard 106. 

Several petitions addressed the labeling of fit- 
tings, as well as hose and assemblies. Two of the 
major concerns, use of the DOT symbol and the 
marking of multi-piece end fittings, ha\e been 
discussed earlier. 

Labeling of brake hose "at intervals of no more 
than six inches, measured from the end of one 
legend to the beginning of the next" can create 
several problems; for example, spray painting 
of a vehicle frame in which hose has been 



PART 571; S 106— PRE 13 



Effective: September 1, 1974 
March 1, 1975 
September 1, 1975 

mounted. Mack argued that the legend need ap- 
pear only once on hose which has been made 
into an assembly and mounted in a vehicle. The 
NHTSA has concluded that the value of the con- 
tinuous line and legend, as a ready source of the 
hose characteristics on bulk hose and as aid to 
untwisted installation, is exhausted when an as- 
sembly has been mounted. Therefore S5.2.2 has 
been modified to require only that the legend 
appear at least once on assemblies mounted in 
vehicles. It is emphasized that masking material 
used in painting must be removed so that the 
labeling does appear on the completed vehicle. 
Only the required information may appear along 
one side of the hose. 

The labeling distance of a maximum 6 inches 
between legends is intended to ensure adequate 
repetition on bulk hose without restricting the 
size of the legend. A manufacturer is free to 
make the legend as short or long as he feels is 
necessary to make the information clear, and on 
this basis, Midland-Ross' petition to require 
labeling at 6-inch intervals measured from the 
beginning of one legend to the beginning of the 
next is denied. Weatherhead expresses confu- 
sion over a Notice 10 preamble reference to the 
complete legend appearing in 4 inches. This 
statement was only intended to illustrate a situa- 
tion where a mixture of optional and required 
labeling would interfere with the appearance of 
complete labeling on some hose assemblies, and 
it did not imply a requirement that the legend 
must be 4 inches long. 

Although no manufacturer specifically re- 
quested a change, the NHTSA has concluded 
that clarity would not be substantially degraded 
by permitting required label information to ap- 
pear in any order. The requirement for a specific 
order of label information has accordingly been 
deleted in order to reduce waste associated with 
hose cutting. The lettering height of one-eighth 
of an inch is considered necessary for clarity and 
will be retained. 

Mack requested confirmation that end fitting 
labeling may be covered with paint until a person 
strips off the paint to read the labeling. This 
interpretation is incorrect. To be useful, label 
information must be clearly visible for easy 
reference. 



Midland-Ross requested clarification of the use 
of the letters "SP". These letters distinguish, 
two types of air brake hose: regular i/^-inch 
hose and hose that requires special reusable fit- 
tings. Tliis is the only situation where different 
hoses share the same size designation. The 
NHTSA cannot agree with Midland that wider 
use of the letters would clarify the use of other 
components. 

Weatherhead challenged as discriminatory the 
required labeling by manufacturers of hose as- 
semblies other than those assembled and installed 
by a vehicle manufacturer in vehicles manufac- 
tured by him. The argument relied in part on 
a statutory requirement that "every manufac- 
turer . . . shall furnish to the distributor or 
dealer at the time of delivery of such vehicle 
or equipment . . . the certification that . . . [it] 
conforms ... in the form of a label or tag . . ." 
(15 U.S.C. §1403). 

This section covers vehicles and equipment only 
"at that time" of delivery" to a distributor or 
dealer. In contrast, the exception in question 
applies to hose assemblies mounted in vehicles 
by their manufacturers which do not fall under 
the language of § 1403. 

Weatherhead also requested an alternative la- 
beling procedure in place of banding which the 
NHTSA has determined is not desirable because 
it detracts from the uniformity of the labeling 
procedure, and accordingly this petition is 
denied. 

Several manufacturers have requested approval 
of specific banding techniques, including a molded 
rubber ring, a metal band crimped together, and 
an adhesive label which adheres to the hose. 
The NHTSA interprets a band as a label which 
encircles the hose completely, and attaches to 
itself. To constitute labeling at all, the band 
must, of course, be affixed to the hose in such a 
manner that it can not be easily removed. 

Manufacturers raised objections to the specific 
performance requirements as they apply to hose 
types. Manufacturers of hydraulic hose assem- 
blies requested exclusion of various types of end 
fittings from the constriction requirements to 
permit L-shaped and T-shaped fittings, distribu- 
tion blocks, and residual valves, which are de- 
signed to have small diameters. The NHTSA 



PART 571; S 106— PRE 14 



has concluded that the major constriction prob- 
lems occur in joining the hose to the fitting, and 
has amended the constriction requirements so 
that they apply only to that part of the fitting in 
which hose is inserted. 

Weatherhead requested a calibration factor 
for the expansion test procedure used with hy- 
draulic hose. Tlie NHTSA explained in its last 
notice that, although calibration factors exist and 
must be taken into account in any performance 
test, it is inappropriate to state a calibration 
factor as part of the performance requirement. 
Weatherhead's petition is accordingly denied. 

Several manufacturers pointed out the inad- 
vertent substitution of "rupture" as the perform- 
ance requirement to be met in the tensile strength 
tests of hydraulic hose and air brake hose. This 
language has been replaced with a requirement 
of no separation of the end fittings from the 
hose. With regard to "rupture", it should be 
noted that the definition of the term was not sub- 
stantively changed in Notice 10, but only re- 
arranged for clarity. 

Another omission has been corrected by the ad- 
dition of language to tlie corrosion resistance re- 
quirements of air and vacuum brake hose fittings 
to allow the same displacement of a protective 
coating which is permitted for hydraulic hose end 
fittings. It is noted for the benefit of manufac- 
turers who have requested interpretation that dis- 
coloration of a brass end fitting is not of itself 
considered to be corrosion. 

Most manufacturers objected to the restrictive 
elements of Table III, making various argiunents 
for increasing the number of sizes available for 
use with reusable fittings. Table III, however, 
is intended to be a first step toward standardiza- 
tion of reusable fittings and hose, and dislocations 
of former practices must be expected in restrict- 
ing the choice of available sizes and types. The 
petitions to eliminate Table III restrictions, or 
to add new sizes to it, are denied for these reasons. 
Weatherhead argued that permanent as well as 
reusable hose should be subject to size limits, but 
the NHTSA has found that this would be a de- 
sign restriction without corresponding safety 
benefit. The hose used witli permanent fittings 
is generally assembled by high volume manufac- 
turers, not repair operations in the field, and the 



Effective: September 1, 1974 
March 1, 1975 
September 1, 1975 

mismatch problem, to which standardization of 
reusable hose is addressed, should not occur. The 
petition is therefore denied. 

In response to Parker-Hannifin's inquiry, the 
NHTSA favors no one fitting type among the 
choice of reusable air brake fittings. 

Stratoflex questioned a leakage requirement in 
a hydrostatic test of air brake hose when at the 
same time an air pressure test permits a limited 
amount of air leakage. The NHTSA makes the 
distinction on the basis of the rubber composition 
which permits air but not water to permeate the 
hose wall. 

With regard to vacuum hose requirements, 
Midland-Ross petitioned for the use of wording 
in S9.2.9 that appeared in Notice 8, believing it to 
be more clear than the language substituted for 
it in Notice 10. On balance, the NHTSA agrees 
that "adjacent layers" accurately describes heavy 
as well as light hose construction, and it is re- 
established. It should be understood that this 
wording includes separation of the outer cover 
from the tube. 

Toyo Kogyo, in a letter request for interpreta- 
tion, questioned a language change between the 
Notice 7 proposal (36 FR 5855, March 30, 1971) 
and the Notice 8 rule, in S9.2.8. The swell test 
of vacuum hose called for "no leakage . . . after 
which there shall be no separation of the inner 
tube from the fabric reinforcement of the hose." 
By error, the Notice 8 requirement instead called 
for no "collapse," which would require absolutely 
no deformation of the hose in terms of decreased 
interior diameter. The NHTSA did not intend 
to increase the requirement and this notice re- 
establishes the intended performance level. It 
should be noted that a "no collapse" requirement 
would have been inconsistent with the shorter 
vacuum test requirements of S9.2.7. 

One manufacturer asked for an explanation of 
the use of "[Reserved]". This term is used in the 
Code of Federal Regulations to indicate an omis- 
sion or deletion, to avoid having to renumber the 
following units. It does not indicate reservation 
for any specific purpose. 

Several minor changes are made to the stand- 
ard -to correct typographical errors found in 
Notice 10. It is also noted that the Notice 10 



PART 571; S 106^PRE 15 



EffecHve: September 1, 1974 
March 1, 1975 
September 1, 1975 

amendment of S5.2.3 appearing in the Federal 
Register appeared to delete paragraph (e), which 
in fact remains in the standard. 

In consideration of the foregoing, both Stand- 
ard No. 106 (49 CFR 571.106) in its presently 
effective form, and Standard No. 106-74 (49 
CFR 571.106-74) as it is effective September 1, 
1974, are amended, 

Effective dates. September 1, 1974, for brake 
hose and brake hose end fittings; March 1, 1975, 



for brake hose assemblies; September 1, 1975, for 
vehicles to which the standard applies. 

(Sees. 103, 112, 114, 119, Pub. L. 89-563, 80 
Stat. 718 (15 U.S.C. 1392, 1401, 1403, 1407) ; 
delegation of authority at 49 CFR 1.51.) 

Issued on June 24, 1974. 

James B. Gregory 
Administrator 

39 F.R. 24012 
June 28, 1974 



PART 571; S 106— PRE 16 



ElhcHv*: March I, 1975 



PREAMBLE TO AMENDMENT TO MOTOR VEHICLE SAFETY STANDARD NO. 106-74 

Brake Hoses 
(Docket No. 1-5; Notice 12) 



This notice amends Standard No. 106-74, 
Brake hoses, 49 CFR 571.106-74, to provide that 
hose assemblies of the same internal diameter 
are subjected to the same tensile strength re- 
quirements. This amendment responds to a 
petition for reconsideration of the most recent 
amendments of Standard No. 106-74 (Notice 11) 
filed by Samuel Moore and Company on July 1, 
1974. 

The National Highway Traffic Safety Admin- 
istration (NHTSA) is responding to this peti- 
tion before considering all other comments on 
Notice 11 because of the effect of this ruling on 
Standard No. 121, Air brake systems, which be- 
comes effective January 1, 1975, for trailers and 
March 1, 1975, for trucks and buses. The design 
and testing of air brake systems for the standard 
has been based in part on the continued avail- 
ability and use of %-inch OD plastic tubing, a 
popular substitute for i^-inch ID hose in some 
tractor-to-trailer applications. Samuel Moore 
has pointed out that, although %-inch tubing 
and i/i'i^^h hose deliver the same air supply 
under the same circumstances, Standard No. 
106-74 subjects the tubing to greater tensile 
strength requirements than hose. As a result the 
tubing may have to be withdrawn from the 
market because it is unable to meet the higher 
requirements. Designers of the new air brake 
systems must know immediately if %-inch tub- 
ing can continue to be used. 

The NHTSA intends that all brake hose sub- 
ject to the standard, including traditional rubber 
hose and the newer plastic tubing, be subject to 
appropriate tests for the environment and use 
in which they serve. In this situation %-inch 



OD tubing has the equivalent bore of 14-inch ID 
hose. The NHTSA hereby amends the standard, 
by adding "in nominal internal diameter" to 
S7.3.10 and S7.3.11 following each size designa- 
tion, to test these products to the same tensile 
strength requirements. 

A typographical error in Notice 11 which 
changed the meaning of the tensile strength re- 
quirements is corrected here by the addition of 
parentheses around the phrase "other than a 
coiled nylon tube assembly which meets the re- 
quirements of § 393.45 of this title" appearing 
in S7.3.10 and S7.3.11. 

Additionally, Notice 11 attempted to resolve 
an ambiguity in Notice 10 concerning the dele- 
tion of subparagraph (e) of S5.2.2 of the stand- 
ard. Notice 11 mistakenly referred to S5.2.3, 
and it should be noted that, in actuality, it was 
the Notice 10 amendment of S5.2.2 appearing in 
the Federal Register that appeared to delete 
paragraph (e), which in fact remains in the 
standard. 

In consideration of the foregoing, Standard 
No. 106-74 (49 CFR 571.106-74) is amended 

Effective date : March 1, 1975. 

(Sec. 103, 119, Pub. L. 89-563, 80 Stat. 718 
(15 U.S.C. 1392, 1407); delegation of authority 
at 49 CFR 1.51.) 



Issued on August 2, 1974. 



James B. Gregory 
Administrator 

39 F.R. 28436 
August 7, 1974 



PART 571; S 106— PRE 17-18 



Effactlve: November II, 1974 



PREAMBLE TO AMENDMENT TO MOTOR VEHICLE SAFETY STANDARD NO. 106-74 

Brake Hoses 

(Docket No. 1-5; Notice 14) 



This notice amends Standard No. 106-74, 
BraJce hoses, 49 CFR 571.106-74, to permit, for 
a limited time, the manufacturing of brake hose 
assemblies whicli comply with the standard in 
all respects except that they are constructed with 
hose or end fittings which do not meet certain 
labeling requirements. 

A notice of proposed rulemaking was pub- 
lished on October 3, 1974 (39 F.R. 35676) (No- 
tice 13), which proposed amendment of the 
standard to facilitate the depletion of inven- 
tories of brake hose that is not properly labeled. 
All of the comments supported the proposal. 
Several of those commenting suggested that the 
proposed temporary exception ro the labeling 
requirements be extended to cover end fittings 
as well as hose. These manufacturers pointed 
to large inventories of end fittings, manufactured 
before September 1, 1974, which meet all of the 
performance requirements of the standard, but 
which could not be used because they are not 
properly labeled. As with the brake hose dis- 
cussed in Notice 13, safety of performance is not 
a major issue. The NHTSA has determined 
that the use of both non-conforming hose and 
end fittings in assemblies manufactured before 
September 1, 1975, while it may make enforce- 
ment by this agency temporarily more difficult, 
is appropriate and in the public interest. 

In its petition for reconsideration of Notice 11 
(39 F.R. 24012, June 28, 1974), Wagner Electric 
Corporation requested an amendment to permit 
the labeling of brake hose assemblies with DOT- 
marked bands in accordance with S5.2.4 before 



March 1, 1975, the date assembly labeling be- 
comes effective. The NHTSA takes this oppor- 
tunity to respond to AVagners petition ahead of 
other petitions for reconsideration of Notice 11 
in order to clarify the standard's scheme of ef- 
fective dates. 

Even though Standard 106-74 has already 
been published, there are no requirements in it 
applicable to air brake hose assemblies or to 
\'acuum brake hose assemblies until March 1, 
1975. Consequently, use of the DOT symbol on 
such assemblies manufactured before that date 
would be inconsistent with the established mean- 
ing of that symbol as a certification of compli- 
ance with applicable standards. Use of the 
symbol to indicate "anticipatory compliance", as 
AVagner has suggested, would foster confusion 
in both the meaning of the symbol and the con- 
cept of the certification required by Section 
108(a)(3) of the National Traffic and Motor 
Vehicle Safety Act of 1966. Accordingly, Wag- 
ner's petition is denied. 

The problem of excessive inventories of pre- 
standard hose and end fittings arose from incor- 
rect assumptions about the effective date of the 
standard as applied to hose assemblies which are 
not completed until the hose is installed in the 
vehicle. No parallel misunderstanding can arise 
with respect to the September 1, 1975 effective 
date for vehicles, so brake hose assemblers can 
plan their production schedules accordingly. 

In consideration of the foregoing, Standard 
No. 106-74 (49 CFR 571.106-74) is amended by 
the addition of a new section .... 



PART 571; S 106— PRE 19 



Effective: November 11, 1974 

Effective date; November 11, 1974. Because Issued on November 6, 1974. 

this amendment relieves a restriction, the Na- 
tional Highway Traffic Safety Administration 

finds, for good cause shown, that an immediate James n. Gregory 

effective date is in the public interest. Administrator 

(Sees. 103, 119, Pub. L. 89-563, 80 Stat. 718 
(15 U.S.C. 1392, 1407) ; delegation of authority 39 F.R. 39725 

at 49 CFR 1.51.) November 11, 1974 



PART 571; S 106— PRE 20 



EffccNva: March 17, 197 S 



PREAMBLE TO AMENDMENT TO MOTOR VEHIQE SAFETY STANDARD NO. 106-74 

Brake Hoses 

(Docket No. 1-5; Notice 16) 



This notice amends 49 CFR 571.106-74, Stand- 
ard No. 106-74, Brake hoses, by modifying sev- 
eral labeling requirements and the deformation 
test requirement for vacuum brake hose, in re- 
sponse to petitions for reconsideration of amend- 
ments which were published June 28, 1974 (39 
F.R. 24012) (Notice 11). Several of the petitions 
are denied; others requested changes which are 
outside the scope of a petition for reconsidera- 
tion, and will be considered as petitions for fu- 
ture rulemaking. 

Ford Motor Company petitioned for relaxation 
of the labeling requirements of the standard as 
they apply to brake hose end fittings. Recog- 
nizing that labeling of all components of an end 
fitting is not feasible, the NHTSA in Notice 11 
interpreted S5.2.3 to require that all unlabeled 
components of an end fitting be made by the 
manufacturer whose designation appears on one 
part. Ford pointed out that, because end fitting 
components made by different manufacturers and 
purchased according to the assembler's specifica- 
tions are virtually interchangeable, this inter- 
pretation would preclude the cost saving practice 
of purchasing individual components from the 
source offering the most favorable price. Because 
most of the performance requirements of the 
standard apply to assemblies, responsibility for 
noncompliance and for safety defects will usually 
belong to the assembler. Accordingly, the stand- 
ard is amended to require labeling on at least one 
component of an end fitting, thus permitting the 
practice of mixing parts from different sources 
to continue as requested by Ford. 

Several vehicle manufacturere petitioned for 
changes in the interpretation of the labeling re- 
quirements, to allow labels on hose and end fit- 
tings to be obscured by paint or by masking 



materials. New information indicates that spray 
painting of end fittings leaves their labeling vis- 
ible in most cases and that, in the occasional in- 
stances where labeling is obscured, excess paint 
may be easily scraped off. In addition, painting 
protects the labels and fittings against corrosion. 
Tlierefore, the NHTSA will not consider the 
painting of end fittings to be a violation of the 
standard. Painting of hose labels, however, pre- 
sents different considerations, because removal 
of paint from a hose may damage both the label 
and the hose. Therefore, the label on a hose must 
remain visible after painting unless it is pro- 
tected by masking which can be removed man- 
ually to permit inspection. Because masking 
material can protect the label from obscuration 
by road grime, and because the expense required 
to remove it after painting does not appear 
jtistified, hose labels may remain masked after 
painting provided that the masking material is 
affixed in such a way that no adhesive contacts 
any part of the label. 

BMAV i^etitioned for a relaxation of the de- 
formation test requireemnts for wire-reinforced 
Aacuum hose. S9.2.10 in its present form requires 
a \-acuum brake hose to return to 90 percent of its 
original diameter within 60 seconds after five 
applications of force as specified in SlO.9. The 
NHTSA has determined that a reduction of the 
90 percent figure to 85 percent will facilitate the 
use of wire-reinforced hose having greater re- 
sistance to collapse under vacuum, and is in the 
public interest. Therefore, BifW's petition is 
granted. 

The Rubber Manufacturers Association (RMA) 
and Gates Rubber Company requested an excep- 
tion to the hose labeling requirement for hose 
lengths shorter than the length of a complete 



PART 571 ; S 106— PRE 21 



231-088 O - TJ - 21 



Effaetiva: March 17, 1975 

legend phis the space between legends. These 
petitions are denied. The NHTSA has no reason 
to believe the hose labeling cannot be reduced in 
length to fit virtually any hose length. The 6- 
inch distance between legends specified in S5.2.2 
is a maximum, and for hose which is to be cut 
into short lengths, this distance can be reduced 
or eliminated. Also, lettering width may be re- 
duced because there is no width requirement in 
S5.2.2 for specified lettering. In addition, Notice 
11 modified the standard to permit the required 
information to appear in any order to facilitate 
hose cutting. 

Kugelfischer Georg Schafer & Co. of Germany 
expressed dissatisfaction with the banding re- 
quirement for brake hose assemblies. Requests 
to eliminate this requirement were responded to 
in Notice 10 (39 F.R. 7425, February 26, 1974). 
Kugelfischer also suggested exemption from the 
banding requirement of assemblers who manu- 
facture both the hose and end fittings in their 
assemblies. Such an exemption would make it 
impossible to identify the assembler of a de- 
fective or noncomplying assembly in which hose 
and end fittings were made by the same manu- 
facturer, and to which no band was attached. 
Therefore the Kugelfischer petition is denied. 

Several manufacturers petitioned for substitu- 
tion of a ball-vacuum test for the adhesion test 
described in S8.6 in the case of a hose which is 
reinforced with wire braid. The RMA petitioned 
for a change in the method of expressing the re- 
sults of the adhesion test, to permit averaging of 
the values recorded on the chart. The NHTSA 
has tentatively found these petitions to have 
merit, and is considering the issuance of a notice 
of proposed rulemaking on these subjects. 

Several of the petitions requested changes 
which are outside the scope of a petition for 
reconsideration of a rule. A petition for recon- 
sideration is appropriate to assert that the peti- 
tioner believes that compliance with the rule as 
issued is not practicable, is unreasonable, or is 
not in the public interest, and to suggest changes 
on that basis (49 CFR 553.35(a)). Requests for 
new requirements that do not contest the appro- 
priateness of the issued ones are properly sub- 
mitted as petitions for rulemaking. Gates and 
the RMA petitioned for an amendment of S7.3.3 
to require an internal as well as external inspec- 



tion of the hose surface after an air brake hose 
is subjected to the low temperature resistance 
test of S8.2. Stratoflex petitioned for changes 
in S7.3.10 and S7.3.11 to require higher tensile 
strength values for hoses used in certain applica- 
tions. Stratoflex also petitioned for the addition 
to 87.3 of a flexion resistance test for air brake 
hose. The NHTSA considers these requests to 
merit further consideration and accordingly, the 
NHTSA will treat these petitions as petitions for 
rulemaking. 

Several inconsistencies resulted from amend- 
ments made to the standard in Notice 11. In 
one case, the modification of the definition of 
"Permanently attached end fitting" inadvertently 
changed the requirements for hydraulic brake 
hose assemblies in S5.1. The modification was 
not intended to permit use of renewable fittings 
in hydraulic brake hose assemblies. Accordingly, 
S5.1 is amended to require that hydraulic brake 
hose assemblies incorporate only those perma- 
nently attached end fittings which are attached 
by deformation of the fittings about the hose 
by crimping or swaging. To correct another 
inadvertent error, S6.7.2(c) is amended to bring 
the brake fluid compatibility t«st for hydraulic 
hose into conformity with the constriction test 
as changed by Notice 11. In response to an in- 
quiry from BMW, new entries are made in Tables 
V and VI to cover %6-inch diameter vacuum hose. 
To clarify the meaning of S5.2.2, the words "may 
appear" in the first paragraph are changed to 
read "need appear". In addition, several typo- 
graphical errors have been corrected. 

In consideration of the foregoing. Standard 
No. 106-74 (49 CFR 571.106-74) is amended 

Effective date: March 17, 1975. Because these 
amendments relieve restrictions and create no 
additional burdens, the NHTSA finds, for good 
cause shown, that an immediate effective date is 
in the public interest. 

(Sec. 103, 119, Pub. L. 89-563, 80 Stat. 718 (15 
U.S.C. 1392, 1407) ; delegation of authority at 
49 CFR 1.51) 

Issued on: March 10, 1975. 

Noel C. Bufe 
Acting Administrator 

40 F.R. 12088 
March 17, 1975 



PART 571; S 106— PRE 22 



Effective: M .rch 1, 1976 



PREAMBLE TO AMENDMENT TO MOTOR VEHICLE SAFETY STANDARD NO. 106-74 

Brake Hoses 
(Docket No. 1-5; Notice 17) 



This notice delays for 6 months the effective 
date of the hose label masking requirements of 
49 CFR 571.106-74 (Standard No. 106-74 Brake 
Hoses), in order to allow time for public com- 
ment on a proposal to eliminate those require- 
ments. 

S5.2.2, S7.2, and S9.1 of the standard require 
certain information to be labeled at intervals of 
not more than 6 inches on new hydraulic, air, 
and vacuum brake hose, respectively. Those re- 
quirements were effective September 1, 1974, 
and are unchanged by this notice. S5.2.2, by 
itself and as incorporated by reference in S7.2 
and S9.1, also requires at least one legend of this 
information to remain either visible after paint- 
ing and undercoating, or properly masked, on 
each brake hose in a completed vehicle. This 
requirement, which as a practical matter requires 
masking, would become effective September 1, 
1975, because it applies to vehicles. The NHTSA 
intends to propose, in the near future, an amend- 
ment of Standard No. 106-74 that would elimi- 
nate the requirement entirely. In order to allow 
time for public comment on the proposal, and to 
permit vehicle manufacturers to defer prepara- 
tion for compliance with a requirement which 
might never become effective, this notice delays 



the effective date of the masking requirement. 
There is no change in the requirement that ve- 
hicles manufactured on or after September 1, 
1975, be equipped with brake hoses, brake hose 
end fittings, and brake hose assemblies that 
comply with the standard. 

In consideration of the foregoing, the effective 
date of the requirement in S5.2.2, S7.2, and S9.1 
of 49 CFR 571.106-74 (Standard No. 160-74, 
Brake Hoses), that hose label information remain 
visible on completed vehicles unless properly 
masked, is changed to March 1, 1976. Because 
of the need to allow time for public comment on 
the prospective proposal to eliminate the require- 
ment, the NHTSA for good cause finds that 
notice and public procedure on the delay are 
impracticable and contrary to the public interest. 

(Sec. 103, 112, 114, 119, Pub. L. 89-563, 80 Stat. 
718 (15 U.S.C. 1392, 1401, 1407) ; delegation of 
authority at 49 CFR 1.15.) 

Issued on July 29, 1975. 

James B. Gregory 
Administrator 

40 F.R. 32336 
August 1, 1975 



PART 571; S 106— PRE 28-24 



Effective: Aujosf 27, 1975 



PREAMBLE TO AMENDMENT TO MOTOR VEHICLE SAFETY STANDARD NO. 106-74 

Brake Hoses 
(Docket No. 1-5; Notice 18) 



This notice amends 49 CFR 571.106-74 (Stand- 
ard No. 106-74, Brake Hoses) to permit, until 
August 31, 1976, the manufacturino; of motor 
vehicles with brake hose, brake liose end fittings, 
and brake hose assemblies -which comply with 
all requirements of the standard except certain 
labeling requirements. 

In a notice published on June 28, 1974 (39 
FR 24012, Docket No. 1-5, Notice 11), the fol- 
lowing scheme of effective dates was established : 
September 1, 1974, for brake hose and brake 
hose end fittings; March 1, 1975, for brake hose 
assemblies; and September 1, 1975, for vehicles 
to which the standard applies. This scheme was 
designed to permit an orderly phase-in of parts 
meeting the new standard, by allowing six 
months at each production stage for the deple- 
tion of inventories of non-conforming parts. 

After the September 1, 1974, effective date for 
hose and fittings, it became apparent that, due 
to a misunderstanding within the industry of the 
standard's requirements, stocks of hose and end 
fittings manufactured before that date would not 
be completely converted into assemblies by the 
March 1, 1975, effective date for assemblies. 
Because the only difference between those non- 
conforming components and hose and fittings 
manufactured after September 1, 1974, appeared 
to be one of labeling, the NHTSA added S12. 
to the standard. That section extended until 
August 31, 1975, the period during which such 
components could be used in assemblies, provided 
that they met all of the standard's performance 
requirements (30 FR 39725, Docket No. 1-5, 
Notice 14). 

Since the publication of Notice 14, there has 
been an unforeseen sharp decline in the produc- 



tion of new trucks, causing several component 
manufacturers, distributors, and vehicle manu- 
facturers to have on hand large inventories of 
hose and end fittings manufactured before 
September 1, 1974, and of assemblies manufac- 
tured from them before March 1, 1975. 

A further extension of the time during which 
these inventories could be exhausted was re- 
quested in petitions for rulemaking filed by 
Parker-Hannifin Corp., Wagner Electric Corp., 
Aeroquip Corp., Samuel Moore and Co., Freight- 
liner Corp., and PACCAR, Inc. These peti- 
tioners indicated that, without such an extension, 
components valued at several hundred thousand 
dollars would have to be scrapped, even though 
they comply fully with all performance require- 
ments of the standard. The petitioners requested 
extensions ranging from 6 to 18 months. 

As with the inventories which were the sub- 
ject of the Notice 14 amendment, safety of per- 
formance is not a major issue. The NHTSA 
has determined that, while granting these peti- 
tions may continue to malce enforcement by this 
agency more difficult until these inventories are 
depleted, the avoidance of waste in this situa- 
tion is appropriate and in the public interest. 
Accordingly, a 1-year extension is granted. It 
should be noted that this amendment makes no 
change in the banding requirement for assemblies 
manufactured on and after March 1, 1975. S13(c) 
is merely intended to facilitate the exhaustion of 
stocks of unhanded assemblies which comply with 
the standard in all other respects. 

Because of the imminent effective date of a 
requirement which would otherwise lead to sub- 
stantial economic waste, the NHTSA for good 
cause finds that notice and public procedure on 



PART 571; S 106— PRE 25 



Effective: August 27, 1975 

this amendment are impracticable and contrarv (Sees. 103, 112, 114, 119, Pub. L. 89-563, 80 

to the public interest. ' Stat. 718 (15 U.S.C. 1392, UOl, 1403, 1407); 

In consideration of the foregoing, 49 CFR delegation of authority at 49 CFR 1.51.) 

571.106-74 (Standard No. 106-74, Brake hoses), Issued on August 22, 1975. 

is amended .... t t, r^ 

^ ^ _ James B. Gregory 

Effective date: August 2<, 1975. Because Administrator 
this amendment relieves a restriction, it is found, 

for good cause shown, that an immediate effec- 40 F.R. 38159 

tive date is in the public interest. August 27, 1975 



PART 571; S 106— PRE 26 



Effactiv*: Septambtr 1, 1976 



PREAMBLE TO AMENDMENT TO MOTOR VEHICLE SAFETY STANDARD NO. 106-74 

Brake Hoses 

(Docket No. 1-5; Notice 20) 



This notice delays until September 1, 1976, the 
effective date of the hose label masking require- 
ments of 49 CFR 571.106-74 (Standard No. 
106-74, Brake Hoses), in order to allow further 
time for evaluation of comments on the proopsetl 
amendment of the standard that would eliminate 
those requirements. 

In its present form, S5.2.2 of the standard (by 
itself and as incorporated by reference in S7.2 
and S9.1) requires at least one legend of labeling 
information to remain either visible after paint- 
ing and undercoating, or properly masked, on 
each brake hose in a completed vehicle. As a 
practical matter, this provision requires masking. 
In Notice 17 (40 F.R. 32336, August 1, 1975), 
the requirement's effective date was set as March 
1, 1976. In Notice 19 (40 F.R. 55365, November 
28, 1975), elimination of the masking require- 
ment and several other labeling requirements was 
proposed. The NHTSA has not concluded its 
evaluation of the comments that have been sub- 
mitted in response to that proposal. In order 
to permit vehicle manufacturers to defei' prepara- 
tion for compliance with a requirement which 



might never become effective, this notice delays 
the effective date of the masking requirement for 
6 months. 

In considration of the foregoing, the effective 
date of the requirement in S5.2.2, S7.2, and S9.1 
of 49 CFR 571.106-74 (Standard No. 106-74, 
Brake Hoses), that hose label infonnation remain 
visible on completed vehicles tmless properly 
masked, is changed to September 1, 1976. Be- 
cause of the need for further evaluation of com- 
ments and the otherwise imminent effective date 
of this requirement, the NHTSA for good cause 
finds that notice and public procedure on this 
delay are impracticable and contrary to the pub- 
lic interest. 

(Sees. 103, 112, 114, 119, Pub. L. 89-563, 80 
Stat. 718 (15 U.S.C. 1392, 1401, 1403, 1407) ; dele- 
gation of authority at 49 CFR l.,50.) 

Issued on February 24, 1976. 

James B. Gregory 
Administrator 

41 F.R. 8783 
March 1, 1976 



PART 571; S lOC^PRE 27-28 



Ellactiv*: July 12, 1976 



PREAMBLE TO AMENDMENT TO MOTOR VEHICLE SAFETY STANDARD NO. 106-74 

Brake Hoses 
(Docket No. 1-5; NoHce 21) 



This notice amends the definitions and several 
labeling requirements of Standard No. 106-74, 
Brake Hoses. The definition of "brake hose as- 
sembly" is amended to exclude certain assemblies 
made in the field from all new components for 
repair service. A definition for "vacuum tubing 
connector' is added, and the definition of "brake 
hose" is amended to exclude such connectors. 
The requirement that certain information remain 
either visible or properly masked on brake hoses 
in completed vehicles — the "masking require- 
ment" — is eliminated. In addition, the require- 
ments that hose be labeled "permanently" and 
that a full legend of information appear on any 
hose, regardless of its length, are eliminated. 

The amendment of the definition in Standard 
No. 106-74 (49 CFE 571.106-74) of "brake hose 
assembly" was proposed in Notice 15 (40 F.R. 
8962; March 4, 1975). The remaining amend- 
ment were proposed in Notice 19 (40 F.R. 55365 ; 
November 28, 1975). Sevently-nine comments 
were received in response to the fonner proposal 
and 14 in response to the latter. Any suggestions 
for changes from the proposals not specifically 
mentioned herein are denied, on the basis of all 
the information presently available to this agency. 

NOTICE 15 

Standard No. 106-74 has required the manufac- 
turer of a brake hose assembly, except a vehicle 
manufacturer who assembles and installs it in a 
vehicle manufactured by him, to affix a band to 
his product. The band must be labeled with the 
date of assembly, a designation identifying him 
as the assembler, and the symbol "DOT" as a cer- 
tification that the assembly meets all applicable 
safety standards. Assemblies made entirely of 
new components for installation in used vehciles 
come from a variety of sources. Among these 



are repair shops, employees of truck fleet owners, 
and even truck owners themselves. Under the 
applicable law, each of these many assemblers is 
a "manufacturer". The NHTSA has concluded 
that, as suggested in Notice 15, the burden of 
affixing a band and certifying compliance with 
the requirements of the standard is not commen- 
surate with the relatively small number of as- 
semblies prepared by such manufacturers. The 
exclusion of the asemblies in question from the 
definition will relieve them of both the banding 
and performance requirements of the standard. 
The Weatherhead Company, Wagner Electric 
Corporation, and the Brake System Parts Manu- 
facturing Council pointed out that the proposed 
amendment of the definition would permit the 
preparation of replacement hydraulic assemblies 
in the field with renewable or useable end fittings, 
because such assemblies would no longer be sub- 
ject to S5.1, which requires hydraulic end fittings 
to be attached by crimping or swaging. The 
NHTSA did not intend such a result. Accord- 
ingly, this notice limits the proposed exclusion 
from the definition of "brake hose assembly" to 
air and vacuum assemblies. 

Paccar pointed out that the driver of a tractor- 
trailer combination is often the owner of the 
tractor but not the trailer, and that the proposed 
amendment would not exclude assemblies made 
in the field by such a driver for installation on 
the trailer that he is towing. For this reason, 
the amendment adopted today also excludes from 
the definition those assemblies prepared by the 
operator of a used vehicle for in.stallation in that 
vehicle. 

Several distributors of brake hose and brake 
hose assemblies urged that the proposed exclusion 
lie extended to cover assemblies made by them as 



PART 571; S 106— PRE 29 



Effective: July 12, 1976 



well. In recognition of the costs of banding, the 
NHTSA has granted petitions for rulemaking to 
eliminate the banding requirentent for all manu- 
facturers of brake hose assemblies. A notice of 
proposed rulemaking on this subject can be ex- 
pected in the near future. Such an amendment 
of the standard, if adopted, will relieve distribu- 
tors of the expense of banding while retaining 
the performance and other requirements appli- 
cable to brake hose assemblies. 

NOTICE 19 

Masking. S5.2.2, S7.2, and S9.1 of the standard 
require certain information to be labeled on new 
hydraulic, air and vacuum brake hose, respec- 
tively. In addition, S5.2.2 in its present form (by 
itself and as incorporated by reference in S7.2 
and S9.1) requires, effective September 1, 1976, 
at least one legend of that information to be 
visible on each brake hose that has been installed 
in a motor vehicle, unless it is covered by a 
manually removable masking material in such a 
way that no adhesive contacts any part of the 
legend. The practical effect of this section, un- 
less amended, would be to require the addition 
of an entire new stage in the vehicle manufac- 
turing process. 

Elimination of the masking requireemnt was 
proposed in Notice 19. All comments in response 
to the notice supported this proposal. The 
NHTSA has concluded that, in light of the lim- 
ited usefulness of the information that would be 
preserved, the masking requirement creates an 
inappropriate burden and should be eliminated. 

Labeling of short hoses. The standard pres- 
ently requires that, effective September 1, 1976, 
a complete legend of labeling information appear 
on every brake hose, regardless of its length. 
Because this would require manual labeling of 
hose shorter than the normal label spacing. Notice 
19 proposed elimination of the "short hose label- 
ing" requirement. No objections were received, 
and the requirement is eliminated accordingly. 
For clarification, the first sentence of S5.2.2 is 
modified to indicate that, for labeling purposes, 
hose need merely be cut from bulk hose that is 
properly labeled. 

Permanent labeling. Also proposed in Notice 
19 was the elimination of the requirement that 



hoses be permanently labeled. Volkswagen ob- 
jected to such elimination, arguing that "if the 
labeling provision has any meaning at all, the 
labeling must be pennanent." Even without a 
performance requirement, however, the informa- 
tion specified in S5.2.2 must appear on bulk hose 
to identify it to distributors, dealers, assemblers, 
and installers, and to facilitate compliance in- 
spection and testing. Because the agency con- 
ducts its compliance tests on new hose and as- 
semblies, these purposes have been fulfilled once 
the hose is put in service. Accordingly, the per- 
manence requirement is deleted from S5.2.2. If 
in the future the agency finds a need to ensure 
preservation of identifying information for the 
life of the hose, a requirement for permanence 
can be established through further rulemaking. 

Vacuum tubing connectors. Bendix Corpora- 
tion petitioned for an amendment of the standard 
that would exclude from its coverage certain 
short flexible connectors used in vacuum brake 
booster systems. These connectors, while meeting 
the existing definition of "brake hose," have spe- 
cial performance requirements that make it in- 
appropriate to subject them to this standard. No 
comments objected to the proposal in Notice 19 
to amend the definition of "brake hose." Wagner 
Electric, however, suggested that the exclusion 
of tubing connectors be limited to those used in 
vacuum systems. Such an approach provides the 
requested accommodation of an existing practice 
that has proved acceptable without encouraging 
the improper design of short air and hydraulic 
brake hoses. Accordingly, the definition of 
"brake hose" is amended to exclude vacuum tub- 
ing connectors. The latter are defined as pro- 
posed, with the modification suggested by AVagner 
Electric. 

The National Motor "Vehicle Safety Advisory 
Council took no position on the proposals of these 
amendments. 

In consideration of the foregoing, 49 CFR 
571.106-74 (Standard No. 106-74, Brake Hoses) 
is amended. . . . 

Effective date: July 12, 1976. Because these 
amendments relieve restrictions and create no 



PART 571; S 106— PRE 30 



Effective: July 12, 1976 

additional burdens, the NHTSA finds, for good Issued on .Inly 7, 197f>. 

cause shown, that an immediate effective date is r t> ^ 

. ,, . T • i. i. .lames li. (ircfjoi-v 

in the public interest. . , • • 

„ Administrator 
(Sees. 103, 112, 114, 119, Pub. L. 80-.563, 80 Stat 

718 (L5 U.S.C. 1,392, 1401, 1403, 1407) ; delepa- 41 F.R. 28505 

tion of authority at 49 CFR 1..50.) July 12, 1976 



PART 571; S 106— PRE 31-32 



Effecllve: November 26, 1976 



PREAMBLE TO AMENDMENT TO MOTOR VEHICLE SAFETY STANDARD NO. 106-74 

Brake Hoses 

(Docket No. 1-5; Notice 22) 



This notice amends Standard No. 106-74, Brake 
Hoses, to permit the manufacturing of brake liose 
assemblies and motor vehicles with brake hose 
and brake hose end fittings which comply with all 
requirements of the standard except labeling re- 
quirements. 

Standard No. 106-74 (49 CFR 571.106-74) was 
implemented with staggered effective dates for 
brake hose, assemblies, and motor vehicles. This 
scheme was designed to permit an orderly 
phase-in of parts meeting the new standard, by 
allowing six months at each production stage for 
the depletion of inventories of non-conforming 
parts. 

Since implementation of the standard, there 
have been interruptions in the production of new 
trucks, causing several component manufacturers, 
distributors, and vehicle manufacturers to have 
on hand large inventories of hose and end fittings 
manufactured before September 1, 1974, and of 
assemblies manufactured from them before March 
1, 1975. These components comply with all per- 
formance requirements of the standard, but not 
its labeling requirement. 

A 1-year extension of the time during which 
these inventories could be exhausted by manufac- 
ture into assemblies and installations in motor 
vehicles was therefore granted (iO F.R. 381.')9, 
August 27, 1975). The NHTSA determined that, 
while granting the petitions could make enforce- 
ment by this agency more difficult until the in- 
ventories were depleted, the avoidance of waste 
in such a situation was appropriate and in the 
public interest. 

The 1-year extension t€rminat«d August 31, 
1976, and PACCAR Corporation has petitioned 
for a further extension of 90 days to permit 
exhausting inventories that it had planned to 
utilize earlier but has been unable to do. Freight- 



liner Corporation petitioned for a similar 15- 
month extension, and Wagner Corporation 
-suggested comparable delay for assemblies and 
vehicles. While the agency cannot make an ex- 
tension "retroactive" to September 1, 1976, as 
PACCAR appeared to request, the NHTSA does 
conclude that the same balance of interests under- 
lying the 1-year extension continue to be valid 
and justify use of the remaining unlabeled com- 
ponents. Because the agency has granted peti- 
tions to commence rulemaking to delete the 
assembly-labeling requirements that are mainly 
at issue here, it is concluded that the relaxation 
of the labeling requirements for assemblies and 
vehicles should be indefinite. As a practical mat- 
ter, brake hose and fittings for use in motor ve- 
hicles are now only produced with the correct 
labeling. 

Because of the agency's findings that substan- 
tial loss of safety benefit would not occur in this 
case and that substantial economic waste will 
occur if the brake hose components in question 
are not permitted to be used, the NHTSA for 
good cause finds that notice and public procedure 
on this amendment is contrary to the public in- 
terest. 

In consideration of the foregoing, Standard No. 
106-74 (49 CFR 571.106-74) is amended. . . . 

E-ffective date: November 26, 1976. Because 
this amendment relieves a restriction, it is found, 
for good cause shown, that all immediate effective 
date is in the public interest. 

(Sees. 103, 112, 114, 119, Pub. L. 89-.563, 80 
Stat. 718 (15 U.S.C. 1392, 1401, 1403, 1407) ; dele- 
gation of authority at 49 CFR 1.50.) 

Issued on November 18, 1976. 

John W. Snow 
Administrator 
41 F.R. 52055 
November 26, 19^6 



PART 571; S 106— PRE 33-34 



Efftcllva: May 25, 1978 



PREAMBLE TO MOTOR VEHICLE SAFETY STANDARD NO. 106-74 

Brake Hoses 

(Docket No 1-5; Notice 24) 



This notice amends Standard No. 106-74, 
Brake Hoses, to exempt hydraulic brake hose to 
be used only in assemblies having keyed end 
fittings from the striping requirement, to exempt 
air and vacuum brake hose assemblies having 
renewable or reusable end fittings from the as- 
sembly labeling requirement, to exempt certain 
end fittings that are to be used on plastic vacuum 
brake hose from the end fitting labeling require- 
ment, to provide for a stamping alternative to 
banding for the labeling of assemblies having 
crimped or swaged end fittings, to exempt coiled 
nylon air brake hose from the length change re- 
quirement for air brake hose, and to exempt wire 
reinforced air brake and vacuum brake hose from 
the adhesion requirements. This rule responds 
to industry requests for less expensive labeling 
alternatives and for relief from several perform- 
ance requirements in the standard that are not 
appropriate for certain hose designs. 

Dates: Effective date: May 25, 1978. 

For further information contact: 

Fred Redler, Crash Avoidance Division, 
National Highway Traffic Safety Adminis- 
tration, Wasliington, D.C. 20590 (202-426- 
0853). 

Supplementary information: This amendment 
is based on a notice of proposed rulemaking 
published December 30, 1976 (41 F.R. 58365). 
Nineteen comments were received in response to 
that notice and were given full consideration in 
the formulation of this final rule. The comments 
were primarily supportive of the proposed 
changes. 

Based on a petition by one committee of the 
American Society for Testing and Materials 



(ASTM), the proposal specified an increase in 
the "brake fluid compatibility" test temperature 
from 200° to 212° F. The" ASTM Committee 
petitioned for the increase so that the tempera- 
ture would be compatible with the equivalent 
100° Centigrade (C) value that has been pro- 
posed for adoption as a standard test tempera- 
ture by the International Standards Organization. 
Several commenters strongly objected to this 
slight increase in the test temperature. Com- 
menters stated that there is no safety justifica- 
tion for the proposed change and that the 
increase, over the 70-hour test period, could 
cause significant changes in test results and lead 
to the rejection of good hose. Four foreign com- 
menters noted that the inner tubing of much 
imported brake hose is made from natural rub- 
ber rather than the synthetic materials that are 
generally used in the United States. They ar- 
gued that this small temperature increase could 
rule out the use of natural rubber, which has 
certain desirable properties and which has other- 
wise proven satisfactory in the past. 

General Motors stated that the International 
Standards Organization has apparently not pro- 
posed a temperature of 100° C for this test and 
that the test temperature for "brake fluid com- 
patibility" should remain at 200°F. The ASTM 
Committee D-11.31 stated that the ASTM 
Committee that i-equested the change (D-11.45) 
was not authorized to seek the change, and the 
ruling ASTM Committee does not approve of 
the temperature increase. 

Based on consideration of these comments, the 
NHTSA has concluded that an increase in tem- 
perature for "brake fluid compatibility" testing 
of brake hose is not justified. Therefore, the 
proposed change is not adopted. 



PART 571; S 106-74— PRE 35 



Effective: May 25, 1978 



This amendment exempts air and vacuum 
brake hose assemblies having renewable or re- 
usable end fittings from the existing labeling 
requirement (banding) for brake hose assemblies 
(by specifying assembly labeling requirements 
only for brake hose assemblies having end fittings 
attached by crimping or swaging). Further, 
the new assembly labeling requirement provides 
for alternative methods of labeling by banding 
or by stamping (or etching or embossing) of 
one end fitting on the assembly. The new provi- 
sions do not require the dat« of assembly to be 
placed on the label, whether banding or stamping 
is used. 

Paccar recommended retention of the existing 
requirement that the date of assembly be included 
in assembly labeling. Paccar contended that date 
of assembly is important for purjjoses of deter- 
mining the shelf-life of an assembly. The NHTSA 
concludes that the assembly date is not necessary 
for this purpose, because it is the brake hose that 
generally determines the assembly shelf-life. 
Since the hose must bear its date of manufacture 
under existing requirements, this should suffice 
as an indicator of the entire assembly's shelf life. 

Several commenters stated that the assembly 
labeling requirements should be deleted alto- 
gether, arguing that brake hose assembly failures 
are most likely to result from installation errors 
and damge in service rather than from improper 
production of the assembly. Samuel Moore and 
Company argued that all assembly labeling 
should be totally optional. '\^^iile data demon- 
strate that most assembly failures result from 
improper installation or later damage, identity 
of the assembler is still important. If assembly 
labeling were not required, only reputable as- 
semblers might identify themeselves with their 
products. The door would be opened to the mar- 
keting of substandard hose assemblies, and there 
would be no way to identify the assembler in 
the event a safety-related defect or a noncom- 
pliance necessitated recall. 

Samuel Moore and Company also stated that 
the proposed assembly labeling requirement 
would discriminate against manufacturers of 
crimped and swaged air brake hose assemblies, 
since the requirements would not be applicable 
to assemblies having renewable or reusable end 



fiittings. The agency did not require labeling 
for assemblies having renewable or reusable end 
fittings because it has been found that such 
labeling is impractical. With reusable end fit- 
tings the assembler's identity could be lost or mis- 
applied by a person who reassembles the set at 
a later date, and the chances for confusion con- 
cerning who assembled the set would be great. 

Paccar commented that the "stamping" option 
for assemblies having cramped or swaged end 
fittings could create confusion also, and that all 
assembly labeling requirements should be deleted. 
While the NHTSA agrees that some confusion 
might exist, labeling of assemblies having per- 
manent end fittings is substantially more prac- 
ticable and offers less possibility for confusion 
than labeling of assemblies having renewable or 
reusable end fittings. Most of the hypotheses 
posed by Paccar involved situations in which 
permanent end fittings are stamped with the 
fitting manufacturer's designation (which is not 
required by the standard). Paccar contends con- 
fusion as to who is responsible for the assembly 
could result when an assembler later applies his 
band to the assembly or when a repair shop in 
the field produces an assembly using stamped 
end fittings. 

Since end fittings that are to be attached to 
hose by crimping or swaging are not required 
to be labeled, the NHTSA concludes that it is 
the responsibility of the fitting manufacturer who 
chooses to stamp his fittings to keep adequate 
records whether a certain production lot of fit- 
tings are sold by themselves or whether they are 
used in assemblies that are also produced by the 
fitting manufacturer. 

Paccar also argued that large assemblers who 
also manufacture end fittings would have an 
economic advantage over assemblers whom they 
supply with end fittings, since end fittings are 
usually stamped with the fitting manufacturer's 
designation. With the stamping labeling alter- 
native, the fitting manufacturer who also makes 
assemblies would not have to further label his 
assemblies, whereas an assembler who purchased 
his end fittings would have to pay either the cost 
of special labeling of end fittings or that of 
banding. 



PART 571; S 106-74— PRE 36 



EffecMve: May 25, IVZII 



The NHTSA recognizes that there are several 
items of higher cost borne by small assemblers but 
disagrees that the assembly labeling requirements 
are discriminatory as suggested by Paccar. As 
mentioned earlier, manufacturers of permanent 
end fittings are not required to label their fittings 
(and if they do so they bear the additional cost 
by choice). Therefore, under the new assembly 
labeling requirements, assemblers who are also 
permanent end fitting manufacturers and small 
assemblers who do not manufacturer end fittings 
are on the same footing; both are required to 
label only once, either by banding or by stamp- 
ing the end fitting. Of course, independent of 
any standard, an assembler who produces all com- 
ponents of his product can generally manufac- 
ture an assembly at a lower cost than an as- 
sembler who purchases components for his 
product. 

Further, from a practical standpoint, the larger 
assemblers who also supply end fittings to smaller 
assemblers are not generally in competition with 
the smaller assemblers. Rather, they deal with 
large volume users in competition with other 
large suppliers. The small assemblers are gen- 
erally only in competition with other small as- 
semblers who are in the same position with 
respect to cost of assembly labeling. The require- 
ments are, therefore, made final as proposed. 

Several commenters pointed out that the notice 
proposing these amendments deleted an existing 
exemption from the assembly labeling require- 
ments of the standard. Assemblies that are as- 
sembled and installed by a vehicle manufacturer 
in vehicles manufactured by him are currently 
excepted from the requirements of paragraph 
S5.2.4. The deletion in the proposal was inad- 
vertent, and the exception is included in the new 
paragraph S5.2.4 specified in this amendment. 

General Motors noted that the proposed new 
paragraph S5.2.4.1 (the stamping option for as- 
sembly labeling) did not specify any criteria for 
the manufacturer's designation and asked 
whether the designation could consist of block 
capital letters or symbols representative of the 
assembler. General Motors also requested concur- 
rence in their assumption that, as a manufacturer 
of both bulk brake hose and hose assemblies, they 



would be permitted under the stamping option 
to use one designation for bulk hose and a dif- 
ferent designation for hose assemblies. Finally 
General Motors recommended that the phrase 
"shall be permanently etched, embossed, or 
stamped," in proposed paragraph S5.2.4.1 and 
in existing paragraph S5.2.4 be changed to read, 
"shall be etched, embossed, or stamped by means 
of deformation of the material." They argued 
that the word "permanently" should be deleted, 
since any marking can eventually be obliterated 
by corrosion, rust, abuse, or other means. 

The NHTSA agrees with the clarification and 
editorial changes requested by General Motors, 
and the changes are included in these amend- 
ments of the hose assembly and end fitting label- 
ing requirements. The NHTSA concurs with 
General Motors' assumption that it is permitted 
to stamp its bulk hose and its assemblies with 
different designations. The word "permanently" 
is deleted from paragraphs S5.2.3 and S5.2.4, as 
it was from paragraph S5.2.2 in a previous notice 
(41 F.R. 28505, July 12, 1976). 

International Harvester objected to the pro- 
posal to exempt hydraulic brake hose used in 
assemblies with keyed end fittings from the strip- 
ing requirement of paragraph S5.2.1. Interna- 
tional Harvester stated that its hose assemblies 
with keyed end fittings are designed with dif- 
ferent orientations for the left and right hand 
sides of vehicles. Each could be installed with a 
20° twist if inadvertently installed on the wrong 
side of the vehicle. Since the striping require- 
ment is intended to prevent twisted installation, 
this amendment only exempts hose for use in an 
assembly whose end fittings prevent its instal- 
lation in a twisted orientation. 

Commenters supported the proposed exemption 
from labeling of end fittings used in factory- 
made, non-repairable plastic vacuum brake hose 
assemblies (such as those used by Mercedes- 
Benz). The proposal is therefore made final. 

Commenters also agreed with the proposed ex- 
emption of coiled nylon air brake hose from the 
"length-change" requirement of paragraph S7.3.6. 
The requirement is therefore amended as pro- 
posed. 



PART 571; S 10&-74r— PRE 37 



Effective: May 25, 1978 



Paragraphs S7.3.7 and S9.2.9 are amended to 
exempt wire-reinforced brake hose from the ad- 
hesion requirements of the standard, since the 
adhesion test does not give sufficiently repeatable 
results in the case of wire-reinforced brake hose. 
A substitute test for this type hose is under con- 
sideration. 

The Dairy Equipment Company stated that all 
assembly labeling requirements were eliminated 
by a notice pubished November 26, 1977 (41 F.R. 
52055) which revised paragraphs S12 and S13 
of the standard. The Company's interpretation 
of that amendment is incorrect. As explained 
in the preamble to that notice, the revision of 
paragraphs S12 and S13 permits the indefinite 
use in new vehicles of hose assemblies manufac- 
tured prior to the effective date of the labeling 
requirement for assemblies. 

This does not mean that new hose end fittings 
and assemblies produced after specific effective 
dates do not have to meet the labeling require- 
ments of the standard. For example, a hose 
assembly manufactured today must bear the re- 
quired assembly labeling even if it is constructed 
of hose or end fittings that do not have DOT 
labeling because they were manufactured prior 
to September 1, 1974. 



Since this amendment relieves restrictions, the 
agency has determined that it will have negligible 
economic impact. The environmental effects of 
the amendments should be positive. Elimination 
of the banding requirement will save approxi- 
mately 30,000 pounds of material annually. 

The engineer and lawyer primarily responsible 
for the development of this rulemaking document 
are Fred Redler and Hugh Oates, respectively. 

Because these amendments relieve restrictions 
and create no addittional burdens, the National 
Highway Traffic Safety Administration 
(NHTSA) finds, for good cause shown, that an 
inunediate effective date is in the public interest. 

In consideration of the foregoing. Standard 
No. 106-74 (49 CFR 571.106-74) is amended 

(Sees. 103, 119, Pub. L. 89-563, 80 Stat. 718 
(15 U.S.C. 1392, 1407; ; delegation of authority 
at 49 CFR 1.50.) 

Issued on May 17, 1978. 

Howard J. Dugoff 
Acting Administrator 

43 F.R. 22360-22362 
May 25, 1978 



PART 571; S 106-74— PRE 38 



PREAMBLE TO AN AMENDMENT TO 
FEDERAL MOTOR VEHICLE SAFETY STANDARD NO. 106 

Federal Motor Vehicle Safety Standards; 
Brake Hoses 

[Docket No. 81-18; Notice 2] 



ACTION: Final rule. 

SUMMARY: The purpose of this notice is to 
amend Safety Standard No. 106, Brake Hoses, to 
make a change in the test procedures relating to 
the brake hose "whip test." Specifically, the list of 
items to be removed from the brake hose 
assembly prior to conducting the "whip test" is 
expanded to include mounting brackets. The 
amendment is responsive to a petition for 
rulemaking submitted by General Motors 
Corporation, and makes the test procedures 
specified in the standard consistent with the test 
procedures used by the agency's Office of 
Enforcement. 

EFFECTIVE DATE: October 22. 1982. 

SUPPLEMENTARY INFORMATION: Safety 
Standard No. 106, Brake Hoses (49 CFR 571.106), 
specifies a "whip test" for hose assemblies to 
measure fatigue resistance. On March 29, 1982, 
the agency issued a notice of proposed 
rulemaking to amend the procedure for that test, 
in response to a petition for rulemaking 
submitted by General Motors Corporation (47 
F.R. 13176). General Motors asked for certain 
changes because of possible confusion between 
the NHTSA's Laboratory Procedures and the 
procedures stated in the standard with respect to 
preparing brake hose assemblies for the "whip 
test." 

The Laboratory Procedure for conducting the 
"whip test" published by the NHTSA Office of 
Standards Enforcement in 1975 ("Laboratory 
Procedure for Brake Hose Testing" TP-106-03) 



specifies the following procedure in preparation 
of the Whip Fatigue Test: "All external 
appendages such as chafing collars, mounting 
brackets, date bands and spring guards shall be 
removed from the brake hose assembly prior to 
testing on the whip machine." By contrast, 
paragraph S6.3.2(a) of Safety Standard No. 106 
specifies the following preparation: "Remove 
hose armor and date band, if any." As noted in the 
March proposal. General Motors was concerned 
that this inconsistency might create confusion, 
and requested that the standard be amended to 
include all the items that are specified for 
removal in the Laboratory Procedure. The notice 
of proposed rulemaking sought to remove the 
inconsistency. 

There were five comments to the proposal from 
the following vehicle manufacturers: Chrysler, 
Ford, American Motors, Volkswagen and General 
Motors. All supported the proposed change and 
stated that it should have absolutely no adverse 
effect on the integrity of the whip fatigue test. 

The agency has determined that this minor 
technical change should be adopted as proposed. 
The agency has always intended for all external 
appendages to be removed prior to conducting 
the "whip test." As noted in the proposal, since it 
is only the brake hose itself that is being tested 
for fatigue resistance, it is not necessary to have 
readily removable external components present 
during the test. Further, these external 
components could unnecessarily complicate the 
test procedure or cause problems by becoming 
caught in the test apparatus. The agency does not 
believe that removing these components will in 
any way degrade the safety performance that is 



PART 571; S106-PRE 39 



garnered from the "whip test." Therefore, the Issued on October 5. 1982. 

standard is being amended as proposed. 



Raymond A. Peck, Jr. 
Administrator 
47 F.R. 47838 
October 28, 1982 



PART 571; S106-PRE 40 



PREAMBLE TO AN AMENDMENT TO 
FEDERAL MOTOR VEHICLE SAFETY STANDARD NO. 106 

Federal Motor Vehicle Safety Standards; 
Brake Hoses 

[Docket No. 82-09; Notice 2] 



ACTION: Final rule. 

SUMMARY: The purpose of this notice is to amend 
Federal Motor Vehicle Safety Standard (FMVSS) 
No. 106, Brake Hoses, by allowing the use of brake 
hoses that are labeled in metric sizes. The agency 
received a petition for rulemaking from Saab- 
Scania to amend Standard No. 106 to allow the use 
of millimeter sizes in the labeling of air brake hose. 
The agency issued a notice of proposed rulemaking 
which proposed to allow manufacturers to label 
their brake hoses with metric units, and provided 
performance requirements in the standard for 
metric-sized brake hoses which were equivalent to 
the present requirements for English-sized hoses. 
This final rule primarily addresses Saab-Scania's 
petition to allow the use of brake hoses manufac- 
tured in metric sizes and is thus more limited than 
the proposal. 

EFFECTIVE DATE: June 3. 1985. 

SUPPLEMENTARY INFORMATION: Federal 
Motor Vehicle Safety Standard (FMVSS) No. 106, 
Brake Hoses, sets performance and labeling re- 
quirements for brake hoses used in motor vehicles. 
Sections 7.2.1(d) and 7.2.2(d) of FMVSS No. 106 re- 
quire that air brake hoses and end fittings be 
labeled for size in inches or fractions of inches. The 
standard currently permits information such as 
metric labeling to be placed on hoses as additional 
information. 

In June 1981, the agency received a petition for 
rulemaking from Saab-Scania to amend sections 
7.2.1(d) and 7.2.2(d) to permit labeling in metric 
units as an alternative to inches. On April 12, 1982, 
the agency published a notice in the Federal 



Register (47 FR 15612) granting the petition and 
proposing that various sections of the standard be 
amended to permit labeling in metric units. 

The notice explained that permitting use of 
metric sizes is consistent with Federal policy con- 
cerning metric conversion and that the proposed 
amendments would aid international harmoniza- 
tion. As the agency has explained in other notices, 
international harmonization can result in de- 
creased costs, benefiting both consumers and 
manufacturers, without an adverse effect on 
safety. In issuing the notice, the agency empha- 
sized that the proposed amendments would not 
make any change in performance criteria ap- 
plicable to a particular size of hose. The notice in- 
cluded performance requirements for the new 
metric sizes of brake hose which were the same as 
the requirements for brake hoses of comparable 
English sizes. 

Although the language of this amendment uses 
the terms "hoses" and "tubing," it is emphasized 
that "brake hose" comprises both terms. Standard 
No. 106 defines "brake hose" as a flexible conduit, 
other than a vacuum tubing connector, manufac- 
tured for use in a brake system to transmit or con- 
tain the fluid pressure or vacuum used to apply 
force to a vehicle's brakes. As explained in past 
Federal Register preambles, the term "brake 
hose" includes traditional rubber hose and plastic 
tubing. All brake hoses are subject to the standard 
and to appropriate tests for the environment in 
which they serve. 

The agency received a number of comments on 
the proposal, all of which have been carefully con- 
sidered. Most commenters supported the concept 
of permitting labeling in metric units. Some com- 
menters suggested various ways to rewrite parts 



PART 571; S106-PRE 41 



of the standard for purposes of clarity or to ad- 
dress safety concerns not directly related to the 
proposal. The agency may consider these sugges- 
tions, as well as other issues, as part of its efforts 
to modernize Standard No. 106 to address current 
technological developments in the industry. How- 
ever, in order to resolve the specific concerns 
raised by the Saab-Scania petition, the agency has 
decided to limit its actions at this time to adopting 
a final rule which directly addresses Saab's petition. 
This final rule permits the use of brake hoses 
and end fittings that are labeled in metric units. In 
response to concerns raised in the comments that 
it might be unclear whether a hose or fitting is 
inch-sized or metric-sized if the unit of measure- 
ment is not included in the label, the final rule re- 
quires that metric labeling include the abbrevia- 
tion "mm" to designate that the labeled units are 
metric. Finally, the final rule does not adopt the 
proposed Table Ill(a). 

Conversion 

Most commenters to the notice of proposed rule- 
making (NPRM) supported the concept of permit- 
ting labeling of brake hoses and end fittings in 
metric units. A number of commenters, however, 
expressed concerns about specific aspects of the 
proposal. 

Several commenters specifically addressed the 
issue of conversions from metric to English units 
or English to metric units. General Motors (GM) 
stated that while the preamble of the NPRM in- 
dicated that metric units of any size would be 
allowed, the actual text proposed for the amended 
standard used only integer units. GM stated that 
this approach appeared to discourage soft conver- 
sions. (A soft conversion is an exact conversion, 
which tends to result in noninteger units, e.g., 1/2 
inch = 12.7 mm. By contrast, a hard conversion in- 
volves rounding off to an integer, e.g., 1/2 inch = 
13 mm.) GM stated that soft conversions may be 
the best interim approach to export products and 
to increase understanding of metrics in this coun- 
try. GM suggested that the easiest way to specify 
the size-related requirements of the standard, 
without discouraging soft conversions, would be to 
establish requirements for a continuum of metric 
sizes. Eaton commented that the proposed amend- 
ment should specify that a manufacturer wishing 
to label a 1/2-inch-outside-diameter (O.D.) tube 
metrically should label this hose "12.7 mm (1/2 in) 
O.D." and not "12 mm O.D." Ford interpreted the 



notice as allowing manufacturers the option of 
labeling brake hoses in either metric or English 
unit sizes. 

Several commenters emphasized that only soft 
conversions should be permitted, unless and until 
industry agrees on hard metric numbers. The Rub- 
ber Manufacturers Association (RMA) stated that 
a 1/4 inch-hose should be marked either 1/4 inch or 
6.4 millimeters until such time as a hose in hard 
metric dimensions is produced. Stratoflex stated 
that United States manufacturei-s have made 
great progress in encouraging the international in- 
dustrial community to standardize on inch-size 
hoses and that it should not be assumed that there 
is any need for the domestic industry to develop a 
line of hoses with whole metric dimensions. 

Other commenters also addressed issues related 
to conversions. Several commenters emphasized 
that inch-size fittings must not be used with metric- 
size hose, since a mismatch could reduce perfor- 
mance and result in accidents. Goodyear objected 
to hard conversions of hose sizes because this 
would encourage the use of English-sized fittings 
with metric-sized hoses (and vice versa) which 
could lead to coupling-compatibility problems. 

In response to the comments on conversions, the 
agency reiterates that NHTSA did not intend to 
encourage conversions of either inch-size or metric- 
size hose or fittings. The agency primarily contem- 
plated that hoses that were manufactured in inch- 
size units would be labeled in inches, and hoses that 
were manufactured in integer metric units would 
be labeled in metric units. The agency intended to 
allow the use of metric-sized brake hoses in the 
American market, using the appropriate metric 
size labeling to denote the "as manufactured" size. 

It should be noted, however, that with the ex- 
ception of air brake hose intended for use with 
reusable end fittings. Standard No. 106 does not 
currently limit the sizes or specify the dimensional 
tolerances of brake hose. While the standard does 
specify some requirements and test conditions in 
terms of specific sizes, the standard does not pro- 
hibit sizes other than those listed, except for air 
brake hose intended for use with reusable end fit- 
tings. Apart from the above exception, manufac- 
turers are not limited to the hose sizes listed in the 
standard. They may produce sizes of brake hose 
other than those listed. The test values for such 
sizes would be provided by reference to the 
nearest appropriate size that is listed in the 
standard. 



PART 571; S106-PRE 42 



Industry has voluntarily standardized the sizes 
and dimensional tolerances of inch size brake hose 
and fittings, primarily through the auspices of the 
Society of Automotive Engineers (SAE). It is 
critical that a hose or fitting marked with an inch 
size correspond dimensionally to accepted in- 
dustry practice. A conversion of a metric-size hose 
to an inch size that resulted in labeling outside the 
scope of accepted industry dimensional practice, 
such as by hard conversions (i.e., rounding off) 
might well constitute a safety defect, since a 
mismatch could result in serious accidents due to 
brake hose assembly failure. It is particularly im- 
portant in the case of air brake tubing and fittings, 
since these are often assembled in repair shops 
rather than in factories where there usually exists 
more control over the matching of hoses and 
fittings. 

Since Standard No. 106 does not limit the sizes 
of most types of brake hose, manufacturers are not 
currently prohibited from using standard metric- 
sized hose if they label the hose sizes in inches. It 
should be emphasized, however, that in proposing 
the amendment, the agency did not intend to en- 
courage conversions of any sort. 

The same analysis discussed above applies to 
converting inch sizes to metric sizes. The agency 
did not intend to encourage these types of conver- 
sions when the amendment was proposed. How- 
ever, if manufacturers choose to make conversions 
of inch sizes into metric sizes, the conversions 
should be within the scope of accepted dimensional 
practice of the international industry. 

Mismatch Problems 

Stratoflex expressed concern that the existence 
in the same marketplace of both inch- and metric- 
size hose and fittings could result in mismatch 
problems. That comment was specifically directed 
toward air brake tubing. Stratoflex's concern ad- 
dressed the definition in Standard No. 106 of "per- 
manently attached end fitting," which includes 
hose fittings which use sacrificial sleeves. 
Stratoflex stated that air brake tubing assemblies 
are often assembled in repair shops by mechanics 
who insert a fitting into a nylon tube and use an or- 
dinary wrench to deform a sacrificial sleeve about 
the outside diameter of the tube to make the con- 
nection. Stratoflex stated that mechanics cannot 
be expected to know the difference between inch 
and metric fittings when neither fitting is marked 
for "size and type control." That commenter stated 



that the agency should either require inch-size air 
brake tubing only, set a date to require metric- 
size air brake tubing only, or establish additional 
marking rules for tubing and tube fittings and 
dimensional control for both inch- and metric-size 
tubing. 

Stratoflex is correct that the standard's defini- 
tion of "permanently attached end fitting" includes 
end fittings that are attached by use of a sacrificial 
sleeve. It is this type of fitting that is typically 
used for air brake tubing. That commenter is incor- 
rect, however, in stating that these fittings need 
not be marked for size. Section S7.2.2 of Standard 
No. 106 requires that end fittings must be labeled 
as to size except for end fittings attached by defor- 
mation of the fitting about a hose by crimping or 
swaging. Crimping or swaging is a process that is 
done by the manufacturer of the hose during the 
assembly of a hose. It does not include using a 
wrench to deform a sacrificial sleeve around 
tubing. This latter type of fitting (i.e., utilizing a 
sacrificial sleeve) would be required to be marked 
as to size. 

Stratoflex stated that the agency should estab- 
lish additional marking rules for dimensional con- 
trol for both inch and metric tubing as currently 
required by Table III of the standard. Table III 
specifies precise dimensions for two nearly iden- 
tical reusable air brake hoses and fittings. They 
are required to be specifically marked as Type AI 
or All, in order to differentiate between these air 
brake assembly components in the field. While 
type control is relevant for reusable air brake 
hose, the agency is not aware of the existence of 
different types or sizes of air brake tubing that 
would necessitate special marking requirements. 

It appears that Stratoflex may be referring to 
the question of whether a hose is inch or metric 
size. While the April 1982 NPRM proposed permit- 
ting labeling in either metric units or inches, the 
proposed language said that the hose could be 
labeled metrically but it did not specifically re- 
quire that the unit of measurement be identified. 
In any event, the agency believes that Stratoflex's 
concerns about labeling are reasonable, and the 
final rule accordingly requires that metric labeling 
include the abbreviation "mm" to designate that 
the labeled units are metric. 

The agency does not agree that this amendment 
permitting the use of metric-sized brake hoses will 
result in mismatch problems. Section 7.2.2 of Stan- 
dard No. 106 currently requires at least one 



PART 571; S 106 -PRE 43 



component of each air brake hose end fitting (ex- 
cept for end fittings that are attached by crimping 
or swaging) to be labeled with information which 
includes the nominal inside diameter of the hose to 
which the fitting is properly attached, or the out- 
side diameter of the plastic tubing to which the fit- 
ting is properly attached. Section 9.1.2 requires at 
least one component of each vacuum brake hose 
fitting (except for end fittings that are attached by 
heat shrinking, interference fit with plastic 
vacuum hose, or crimping and swaging) to be 
labeled in a similar manner. These labeling re- 
quirements are not specified for hydraulic brake 
hose assemblies because section 5.1 of the stan- 
dard requires each hydraulic brake hose assembly 
to have end fittings which are permanently at- 
tached by crimping or swaging. This final rule 
allows the end fittings to be labeled metrically, and 
the information provided on the end fittings to be 
expressed metrically. Since all hoses and end fit- 
tings that are assembled by mechanics will be 
labeled in inch or metric units, assemblers should 
have no difficulty in correctly matching hoses and 
end fittings. 

Table IIKaJ 

The agency has decided not to adopt the pro- 
posed Table Ill(a) in this final rule. Table Ill(a) 
specified physical dimensions for metric sizes of 
air brake tubing intended for use with reusable 
end fittings. Since the time of the proposal of Table 
Ill(a), however, the industry has moved to stan- 
dardize on the sizes of air brake tubing labeled in 
metric units. Dimensional requirements for metric- 
sized air brake tubing has been specified by the 
SAE in Standard J1394 (April 1983). These speci- 
fications are equivalent to those proposed in Table 
Ill(a) by NHTSA. Similarly, the International 
Standards Organization (ISO) has moved towards 
the development of specifications for metric-sized 
air brake tubing in its draft form of TC22-SC2- 
WGl-173(e). Since the industry has moved to 
voluntarily standardize on sizes of metrically 
labeled brake tubing, the agency has decided it is 
unnecessary to specify dimensional requirements 
for air brake tubing at this time. 

Tables IV, V, VI 

Table IV of Standard No. 106 specifies test 
cylinder radii for air brake hoses of varying 
diameters. Hoses must not show visible cracks as a 
result of exposure to various test conditions, such 



as low temperatures, when bent around the test 
cylinder. Table V lists test requirements for high 
and low temperature resistance, bend, and defor- 
mation tests for vacuum brake hose, specifying the 
test values for different sizes of hose. Table VI pro- 
vides test specimen dimensions and feeler gage 
dimensions for the deformation test for vacuum 
brake hoses. Presently the sizes of brake hoses 
referenced in these tables are in inch-size units. 
The amendment would provide the test values for 
specified sizes of metric-sized brake hoses as well 
as for the inch-size hoses. 

Several commenters addressed the changes in 
Tables IV, V, and VI, proposed in the NPRM. 
Stratoflex suggested changes in the millimeter 
sizes referenced in Table IV and requested the 
table's column heading be changed to read 
"Nominal inside hose diameter in inches (milli- 
meters)." The requirements of Table IV were 
previously specified on the basis of the inside 
diameter of the hose. However, in February 1974 
(39 FR 7428), the agency revised the table to read 
"Hose, nominal diameter in inches." Since nominal 
diameter of traditional rubber hose refers to inter- 
nal diameter and nominal diameter of tubing re- 
fers to outside diameter, the revision was made to 
include outside dimensions. In light of this revi- 
sion, the agency does not find reason to change 
this column heading as suggested by this 
commenter. 

Stratoflex also suggested deleting references to 
5-, 8-, 10-, and 16-millimeter sizes in Tables V and 
VI, or adding these sizes to Table Ill(a). This sug- 
gestion was made in order to "maintain consisten- 
cy in the document." In response to this comment, 
the agency notes that Table Ill(a) was proposed for 
sizes of metric air brake tubing, while Tables V 
and VI reference metric vacuum brake hose sizes. 
These metric sizes represent the sizes of metric 
brake hoses "as manufactured," and include all the 
sizes of metric brake hoses currently in use. Since 
the metric sizes listed in the tables are not conver- 
sions but instead represent actual sizes of metric 
hose presently manufactured, the various metric 
sizes proposed in Table Ill(a) for air brake tubing 
and in Tables V and VI for vacuum brake tubing 
would not be identical. 

The RMA commented that the metric units 
referenced in Tables IV and V of the NPRM imply 
hard conversions of the inch dimensions. The com- 
menter stated that hard conversions have not been 
adopted by the industry. The agency reiterates 



PART 571; S106-PRE 44 



that the metric sizes referenced in the tables were 
not intended to represent conversions of inch-size 
hose, but were included in the tables for brake 
hose manufactured in metric sizes. The metric 
sizes listed in the tables represent all metric-sized 
brake hose currently being manufactured in the in- 
ternational industry. By referencing these sizes in 
the tables, the agency intended to provide the test 
values for these specific sizes of metric-sized brake 
hoses. 

In order to avoid any appearance that metric 
values inserted in the tables constitute conver- 
sions, the agency has revised the proposed tables. 
Separate columns or rows are provided for inch- 
size hoses and metric-size hoses. 

American Motors Corporation noted a mixture 
of dimensional systems in Tables I through IV, 
and suggested referencing the Systeme Interna- 
tional d'Unites (SI) system for labeling brake hose 
at all applicable places in these tables. The agen- 
cy interprets this comment to suggest using base 
units of the SI system in the standard. This ap- 
proach would be impractical as the base unit of 
SI, for length is the meter. NHTSA believes that 
the use of the derived SI unit, the millimeter, will 
result in a comprehensible and uniform system of 
measurement. 

Test Requirements 

Eaton commented that a 6-mm O.D. tube it 
tested that was coupled with a metric fitting did 
not meet the 50-pound tensile load requirement of 
S7.3.10. The commenter expressed concern 
whether the current performance criteria of the 
standard could be directly applicable to the metric 
sizes specified in Table Ill(a). The agency sees no 
reason why a metric-size hose would not pass the 
same requirements as for an inch-size hose of 
similar dimensions, and has concluded that no 
changes need be made to these requirements for 
the metric-size hoses referenced in the final rule. 

Eaton commented that S7.3.10 should reference 
"9 mm" instead of "10 mm" in paragraph 7.3.10 for 
the 150 pounds tensile requirement. Currently the 
tensile strength requirements of S7.3.10 specify 
that air brake hose assemblies with nominal inter- 
nal diameters of 3/8 inch or 1/2 inch must with- 
stand a pull of 150 pounds. The agency decided 
against requiring a brake hose with nominal inter- 
nal diameter of 9 mm to withstand a 150-pounds 
tensile strength requirement because a hose of 
this size is less than 3/8 inch in nominal internal 



diameter. As announced in the NPRM, in pro- 
posing this amendment allowing the use of metric- 
sized brake hoses, the agency did not intend to 
change the performance criteria applicable to a 
particular size of hose. Therefore, hoses with 
nominal internal diameters less than 3/8 inch will 
continue to meet the 50-pounds test of S7.3.10. 

Braid Reinforcement 

Eaton raised the issue of air brake tubing con- 
struction. According to that commenter, nonmetal- 
lic air brake tubing manufactured in the United 
States which complies with Standard No. 106 also 
complies with the requirements of SAE Standard 
J844d. SAE J844d requires the use of fiber rein- 
forcement in hose sizes 3/8 inch through 3/4 inch 
outside diameter. Eaton expressed concern that 
the ISO's draft proposal for Thermoplastic Tubing 
for Use in Air Brake Systems does not require the 
use of fiber reinforcement in the larger sizes of 
such hose, and suggested that the metric sizes of 
air brake hose also be required to comply with the 
SAE construction parameters. This amendment to 
Standard No. 106 does not require fiber reinforce- 
ment for these larger sizes of air brake tubing, 
since this final rule is limited to the issues raised 
by Saab-Scandia's petition. However, if in the 
future it becomes apparent that construction re- 
quirements for air brake tubing should be included 
in Standard No. 106, then the agency will address 
that issue at the proper time. 

In consideration of the foregoing. Standard No. 
106, Brake Hoses, 49 CFR Part 571.106, is 
amended to read as set forth below. 

1. S5.2.2(d) is revised to read as follows: 

(d) The nominal inside diameter of the hose ex- 
pressed in inches or fractions of inches, or in 
millimeters followed by the abbreviation "mm." 

2. In table 1, the column entitled "Hydraulic 
brake hose, inside diameter" is amended by re- 
vising the phrase "1/8 inch or less" to read "1/8 
inch or 3 mm or less"; by adding the phrase "or 4 to 

5 mm" after the phrase "3/16 inch"; and by revising 
the phrase "1/4 inch or more" to read "1/4 inch or 

6 mm or more." 

3. Table II is amended by revising the headings 
under the phrase "Slack, inches" to read: "1/8 inch 
or 3 mm hose or less" and "more than 1/8 inch or 3 
mm hose." 

4. S6.6.1(b) is revised to read as follows: 

(b) Condition a cylinder in air at minus 40 °F for 
70 hours, using a cylinder of 2 1/2 inches diameter 



PART 571; S 106 -PRE 45 



for test of hose less than 1/8 inch or 3 mm, 3 inches 
for tests of 1/8 inch or 3 mm hose, 3 1/2 inches for 
tests of 3/16 and 1/4 inch hose or of 4 to 6 mm hose, 
and 4 inches for tests of hose greater than 1/4 inch 
or 6 mm in diameter. 

5. S7.2.1(d) is revised to read as follows: 

(d) The nominal inside diameter of the hose ex- 
pressed in inches or fractions of inches or in 
millimeters, or the nominal outside diameter of 
plastic tubing expressed in inches or fractions of 
inches or in millimeters followed by the letters 
O.D. The abbreviation "mm" shall follow hose sizes 
that are expressed in millimeters. (Examples of in- 
side diameter: 1/8, 1/2 [1/2SP in the case of 1/2 inch 
special air brake hose], 4 mm, 6 mm. Examples of 
outside diameter: 1/4 O.D., 12 mm O.D.) 

6. S7.2.2(d) is revised to read as follows: 

(d) The nominal inside diameter of the hose to 
which the fitting is properly attached expressed in 
inches or fractions of inches or in millimeters, or 
the outside diameter of the plastic tubing to which 
the fitting is properly attached expressed in inches 
or fractions of inches or in millimeters followed by 
the letters O.D. (See examples in S7.2.1(d).) The ab- 
breviation "mm" shall follow hose sizes that are 
expressed in millimeters. 

7. Table IV is revised to read: 

TABLE IV, AIR BRAKE HOSE DIAMETERS AND TEST CYLINDER RADII 



Nominal hose diameter, in.* 


1/8 


3/16 


1/4 


5/16 


3/8,13/32 


7/16, 1/2 


5/8 


mm.* 


3 


4.5 


6 


8 


10 


12 


16 


Radius of test cylinder 
in incties 


1 1/2 


2 


2 1/2 


3 


3 1/2 


4 


4 1/2 



'Ttiese sizes are listed to provide test values for brake tioses manufactured 
in tfiese sizes. Ttiey do not represent conversions, 

8. S7.3.10 amended by revising the section to read: 
S7.3.10 Tensile strength. An air brake hose 

assembly (other than a coiled nylon tube assembly 
which meets the requirements of §393.45 of this 
title) designed for use between frame and axle or 
between a towed and a towing vehicle shall with- 
stand, without separation of the hose from its end 
fittings, a pull of 250 pounds if it is 1/4 inch or less 
or 6 mm or less in nominal internal diameter, or a 
pull of 325 pounds if it is larger than 1/4 inch or 
6 mm in nominal internal diameter. An air brake 
hose assembly designed for use in any other appli- 
cation shall withstand, without separation of the 
hose from its end fitting, a pull of 50 pounds if it is 
1/4 inch or 6 mm or less in nominal internal diame- 
ter, 150 pounds if it is 3/8 or 1/2 inch or 10 mm to 
12 mm in nominal internal diameter, or 325 pounds 
if it is larger than 1/2 inch or 12 mm in nominal in- 
ternal diameter (S8.9). 

9. S7.3.11 is amended by revising the section to read: 



S.7.3.11 Water absorption and tensile 
strength. After immersion in distilled water for 
70 hours (S8.10), an air brake hose assembly 
(other than a coiled tube assembly which meets 
the requirements of §393.45 of this title) designed 
for use between frame and axle or between a towed 
and a towing vehicle shall withstand without 
separation of the hose from its end fittings a pull of 
250 pounds if it is 1/4 inch or 6 mm or less in nominal 
internal diameter, or a pull of 325 pounds if it is 
larger than 1/4 inch or 6 mm in nominal internal 
diameter. After immersion in distilled water for 
70 hours (S8.10), an air brake hose assembly de- 
signed for use in any other application shall with- 
stand without separation of the hose from its end 
fitting a pull of 50 pounds if it is 1/4 inch or 6 mm or 
less in nominal internal diameter, 150 pounds if it is 
3/8 inch or 1/2 inch or 10 to 12 mm in nominal inter- 
nal diameter, or 325 pounds if it is larger than 1/2 
inch or 12 mm in nominal internal diameter (S8.9). 

10. S9. 1.1(d) is revised to read as follows: 

(d) The nominal inside diameter of the hose ex- 
pressed in inches or fractions of inches or in 
millimeters, or the nominal outside diameter of 
plastic tubing expressed in inches or fractions of 
inches or in millimeters followed by the letters OD. 
The abbreviation "mm" shall follow hose sizes that 
are expressed in millimeters. (Example of inside 
diameter: 7/32, 1/4, 4 mm. Example of outside 
diameter: 1/4 O.D., 12 mm O.D.) 

11. S9.1.2(d) is revised to read as follows: 

(d) The nominal inside diameter of the hose to 
which the fitting is properly attached expressed in 
inches or fractions of inches or in millimeters, or the 
outside diameter of the plastic tubing to which the 
fitting is properly attached expressed in inches or 
fraction of inches or in millimeters followed by the 
letters O.D. (See examples in S9.1.1(d).) The ab- 
breviation "mm" shall follow hose sizes that are ex- 
pressed in millimeters. 

12. In tables V and VI, column 1, referring to 
hose inside diameter is amended by changing it to 
read (note: columns after column 1 remain unchanged): 

Issued on January 22, 1985. 



Diane K. Steed 
Administrator 



50 FR 4688 
February 1, 1985 



PART 571; S106-PRE 46 



TABLE V — VACUUM BRAKE HOSE TEST REQUIREMENTS 



Hose Inside Diameter 


• 


High Temp. Resistance 




Low Temp. Resistance 




Inches 


Millimeters 


Hose Length, 
inches 


Radiysof 
Cylinder 
mches 


Hose Length, 
inches 


Radius of 
Cylinder 
inches 


7/32 


5 


8 


1 1/2 


17 1/2 


3 


1/4 


6 


9 


1 1/2 


17 1/2 


3 


9/32 


- 


9 


1 3/4 


19 


- 


11/32 


8 


9 


13/4 


19 


— 


3/8 


10 


10 


1 3/4 


19 


— 


7/16 


- 


11 


2 


- 


- 


15/32 


- 


11 


2 


- 


- 


1/2 


12 


11 


— 


— 


— 


5/8 


16 


12 


— 


— 


— 


3/4 


— 


14 


- 


- 


— 


1 


- 


16 


- 


- 


- 



•These sizes are listed to provide test values for brake hoses manufactured in these sizes. They do not represent conversions. 



TABLE VI— DIMENSIONS OF TEST SPECIMEN AND FEELER GAGE FOR 
DEFORMATION TEST 



Hose 


nside 




Specimen 


Feeler 


gage 


diameter* 




dimensions 


d 


mensions 








(see fig. 4) 












(Vim. 


Depth Length 


Width 




Thickness 






(inch) (inch) 


(inch) 




(inch) 


7/32 




5 


3I6A 1 


1/8 




3/64 


1/4 




6 


1/16 1 


1/8 




1/16 


3/32 




— 


1/16 1 


1/8 




1/16 


1 1/32 




8 


5/64 1 


3/16 




3/64 


3/8 




10 


3/32 1 


3/16 




3/32 


7/16 




— 


5/64 1 


1/4 




5/64 


1502 




— 


3/64 1 


1/4 




5/64 


1/2 




12 


1/8 1 


1/4 




1/8 


5/8 




16 


3/32 1 


1/4 




5/32 


3/4 




— 


3/16 1 


1/4 




3/16 


1 




- 


1/4 1 


1/4 




1/4 



'These sizes are listed to provide test values for brake hoses manufactured 
in these sizes. They do not represent conversions. 



PART 571; S106-PRE 47-48 



PREAMBLE TO AN AMENDMENT TO 
FEDERAL MOTOR VEHICLE SAFETY STANDARD NO. 106 

Brake Hoses 



(Docket No. 82-02; Notice 3) 



ACTION: Final rule. 



SUMMARY: This notice amends the air brake hose 
adhesion test of Federal Motor Vehicle Safety 
Standard No. 106, Brake Hoses. The adhesion test 
is included in FMVSS No. 106 to assure that the 
various layers of an air brake hose do not separate 
in service. The test measures the force required to 
separate adjacent layers of a brake hose. This rule 
amends the standard to exclude the force levels 
recorded during the initial and final 20 percent of 
the testing from the calculation of adhesion value. 
The agency believes that those data should be ex- 
cluded because they can be artificially influenced 
by variables other than the actual adhesion of the 
brake hose layers. This rule also changes the test 
apparatus used to measure adhesion value. The 
new apparatus, a tension-type machine, is more 
widely used by test laboratories than the 
pendulum-type apparatus currently referenced in 
the standard, and provides more valid and con- 
sistent data. 

This rulemaking action commenced in response 
to a petition for rulemaking submitted by the B.F. 
Goodrich Company. 

EFFECTIVE DATE: July 6, 1986. In addition, this 
rule provides for an optional immediate effective 
date. 

SUPPLEMENTARY INFORMATION: On February 
18, 1982, the agency published a notice (47 FR 
7293) granting a petition for rulemaking submitted 
by the B.F. Goodrich Company (Goodrich) and re- 
questing comments on the issues raised by the peti- 
tion. Goodrich's petiton concerned technical 
changes to the adhesion test for air brake hoses set 
forth in Federal Motor Vehicle Safety Standard 
(FMVSS) No. 106, Brake Hoses. That company re- 



quested the agency to adopt two changes to the 
adhesion test: (1) that adhesion value, i.e., the 
force required to separate adjacent layers of a 
brake hose, be determined by an averaging techni- 
que rather than by the current method of using the 
minimum force recorded during the test; and, (2) 
that the force levels recorded in separating the 
layers of the brake hose at the beginning and end 
of the test be disregarded. 

Comments were received on the advantages and 
disadvantages of specifying an average adhesion 
value and disregarding portions at the ends of the 
test chart. After considering those comments, the 
agency concluded that the current method of 
determining adhesion value by an absolute 
minimum value furthers the interests of safety. 
Accordingly, in a notice of proposed rulemaking 
(NPRM) issued in May 1985, NHTSA terminated 
further rulemaking as to that portion of Goodrich's 
petition requesting that an averaging technique be 
used. (50 FR 21090; May 22, 1985.) However, that 
notice also announced that the agency had ten- 
tatively determined that a portion of the test chart 
should be excluded from the calculation of adhesion 
value, and proposed to revise S8.6.4 to set this ex- 
cluded portion at the first and last 20 percent of 
the adhesion test chart. 

Testing Brake Hose Adhesion 

The adhesion test is included in FMVSS No. 106 
to ensure that the various layers of a brake hose do 
not separate in service. Low adhesion in brake 
hoses can result in the build-up of air between 
plies. The trapped air can cause inward ballooning 
of the hose, resulting in slow reaction of the brakes 
served, or a complete malfunction due to the hose 
conduit being blocked altogether. 



PART 571; S 106-PRE 49 



The first step of the adhesion test procedure is to 
cut a specimen of brake hose, one inch or more in 
length. The specimen is then cut longitudinally 
along its entire length to the level of contact with a 
lower layer. The layer to be tested is peeled back 
along the longitudinal cut so as to create a flap 
large enough to be attached to a test apparatus. 
The test apparatus applies tension in a direction 
essentially perpendicular to the axis of the brake 
hose so as to separate, i.e., unroll, the layer being 
tested from the rest of the brake hose. A chart is 
produced which has inches of separation as one 
coordinate and applied tension as the other. 
Paragraph S7.3.7 requires that, except for hose 
reinforced by wire, an air brake hose must with- 
stand a tensile force of eight pounds per inch of 
length before the adjacent layers separate. 
Paragraph S8.6.4 of the standard provides that 
adhesion value— i.e., the force required to separate 
adjacent layers of a brake hose— is "the minimum 
force recorded on the portion of the chart cor- 
responding to the actual separation of the part 
being tested." 

Disregarding Force Levels at Beginning and End of 
Test 

Goodrich requested that the force levels recorded 
on the beginning and end of the test chart be 
disregarded because adhesion between layers 
might be disturbed during sample preparation, and 
because samples can distort near the end of the 
test, resulting in erratic values. The February 1982 
notice requested comments on this issue. Several 
comments where received, all of which have been 
discussed in the May 1985 NPRM. 

Most of the commenters agreed that an excluded 
area at each end of the test curve was necessary, 
but were divided as to how much of the chart 
should be disregarded. Porter and Aeroquip 
agreed with Goodrich that the beginning and end 
of the chart should be excluded because those por- 
tions are affected by variables resulting from sam- 
ple preparation. Goodyear stated that the initial 
and final 20 or 25 percent of the test chart could be 
spurious because of distortion or mechanical ef- 
fects, and believed that amending the standard to 
exclude those portions would be reasonable and ac- 
ceptable. Midland Ross and Blue Bird commented 
that disregarding the beginning and end of the 



adhesion test chart has merit, but that 20 percent 
on either side was too much to exclude. 

After considering those comments, the agency 
proposed a change to Standard No. 106 along the 
lines suggested by Goodrich. (50 FR at 21092.) 
NHTSA believed that an excluded area at each end 
of the test curve might be necessary because the 
end points on the test curve appeared to vary con- 
siderably depending on the sensitivity of the re- 
cording device and variation of sample prepara- 
tion. A 20 percent exclusion zone was proposed 
since the agency believed that this area would not 
result in any safety problems and would cover the 
portions of the chart which were artificially in- 
fluenced by variables other than the actual adhe- 
sion of the hose layers. This change was intended 
to ensure that the remaining portion of the test 
chart corresponds more accurately to the actual 
adhesion value of a brake hose specimen. 

Goodyear was the only commenter to the NPRM. 
That company concurred with the proposed 
changes and reiterated its belief that the initial and 
final 20 or 25 percent of the adhesion test trace 
could be spurious because of distortion or 
mechanical effects, and should therefore be 
excluded. 

This rule amends paragraph S8.6.4(a) of Stand- 
ard No. 106 to specify that the actual separation of 
the part of the brake hose being tested shall be 
determined by excluding the protion of the chart 
which corresponds to the initial and final 20 per- 
cent of the separation distance along the chart's 
displacement axis. NHTSA has concluded that this 
excluded area would cover the portions of the chart 
which are artificially influenced by variables other 
than the actual adhesion of the hose layers, and 
that safety would not be negatively affected by this 
change. 

As explained in the NPRM, each air brake hose 
tested for compliance with Standard No. 106 must 
meet the adhesion test requirement regardless of 
the specimen tested. Disregarding 20 percent at 
the beginning and end of the chart yields test 
results for 60 percent of the test specimen. This 
does not mean that 40 percent of the hose is not 
tested to the adhesion requirements of the stand- 
ard. Multiple specimens of the brake hose can be 
oriented on the test apparatus so that test results 
for the entire circumference of the hose can be 
obtained. Several one inch long test specimens are 



PART 571; S 106-PRE 50 



usually cut from a single piece of hose. These addi- 
tional samples are each individually cut axially in 
preparation for the adhesion test. Another hose 
specimen, adjacent to the original specimen, can be 
tested for compliance, with the cut made at a dif- 
ferent point from the original. The portion of the 
air brake hose falling within the 40 percent range 
that was disregarded in the first test can thus be 
included in the portion of the hose tested for com- 
pliance in a subsequent test. 

Test Apparatus 

Paragraph S8.6.1 of FMVSS No. 106 currently 
references a pendulum type test apparatus in the 
adhesion test procedure. The NPRM proposed to 
reference a tension-type test apparatus in its place. 
The tension-type apparatus is commonly available 
and widely used in brake hose testing laboratories. 
This type of machine is a constant-speed, pulling 
device whose rate of pull can be set to the required 
in the standard. A load cell is utilized to measure 
the resistive load of the bonded layers of hose as 
they are separated by the machine. 

Goodyear, the only commenter to the NPRM, 
concurred with this change. Since NHTSA believes 
that the tension-type apparatus is widely used and 
provides more valid and consistent data than the 
pendulum apparatus, this rule amends S8.6.1 as 
proposed. 

Effective Date 

These amendments are effective July 6, 1986. In 
addition, this rule provides for an optional im- 
mediate effective date. The agency finds good 
cause for an optional immediate effective date 
since the amendments clarify the method of 
calculating the actual adhesion value of a brake 
hose. Further, there is good cause for specifying an 
optional immediate effective date for use of the 
tension-type test apparatus since most, if not all, 
compliance testing is presently done on this 
machine. The alternative effective date of 180 days 



after publication of this rule in the Federal Register 
would provide adequate leadtime for any users 
presently testing with a pendulum or inclination 
balance type apparatus. 

In consideration of the foregoing, 49 CFR Part 
571 is amended as follows: 

S8.6.1 Apparatiis. 

A tension testing machine that is power-driven 
and that applies a constant rate of extension is 
used for measuring the force required to separate 
the layers of the test specimen. The apparatus is 
constructed so that: 

(a) The recording head inlcudes a freely rotating 
form with an outside diameter substantially the 
same as the inside diameter of the hose specimen 
to be placed on it. 

(b) The freely rotating form is mounted so that 
its axis of rotation is in the plane of the ply being 
separated from the specimen and so that the ap- 
plied force is perpendicular to the tangent of the 
specimen circumference at the line of separation. 

(c) The rate of travel of the power-actuated grip 
is a uniform one inch per minute and the capacity 
of the machine is such that maximum applied ten- 
sion during the test is not more than 85 percent 
nor less than 15 percent of the machine's rated 
capacity. 

(d) The machine produces a chart with separa- 
tion as one coordinate and applied tension as the 
other. 

S8.6.4(a) The adhesion value shall be the 
minimum force recorded on the chart excluding 
that portion of the chart which corresponds to the 
initial and final 20 percent portion along the 
displacement axis. 



Issued on December 31, 1985 



Diane K. Steed 
Administrator 

51 F.R. 603 
January 7, 1986 



PART 571; S 106-PRE 51-52 



PREAMBLE TO AN AMENDMENT TO 
FEDERAL MOTOR VEHICLE SAFETY STANDARD NO. 

Brake Hoses 
(Docket No. 85-02; Notice 2) 



106 



ACTION: Final Rule. 

SUMMARY: The purpose of this notice is to amend 
Federal Motor Vehicle Safety Standard (FMVSS) 
No. 116, Motor Vehicle Brake Fluids, and FMVSS 
No. 106, Brake Hoses, to revise the referee 
materials and test procedures referenced in por- 
tions of those standards. FMVSS No. 116 and 
FMVSS No. 106 currently reference the referee 
material (RM) identified as RM-1 fluid by the 
Society of Automotive Engineers (SAE). However, 
RM-1 fluid is now commercially unavailable, and is 
less representative of brake fluids used in vehicles 
on the road today. The SAE in its January 1980 
revision of Standard J1703, "Motor Vehicle Brake 
Fluid," substituted a new referee material, 
RM-66-03, in place of RM-1 for use in the J1703 
compatibility test. This final rule adopts this 
revision and references RM-66-03 for use in the 
compatibility test of Standard No. 106, and the 
compatibility and fluid chemical stability tests of 
Standard No. 116. This notice also references a 
new referee material, TEGME, in the humidifica- 
tion procedure of Standard No. 116, adjusts the 
water content level and test temperature refer- 
enced in the test procedures, and amends the 
number of sets of stroking test materials in the 
stroking test procedures. This notice also makes 
procedural modifications to Standard No. 116's 
humidification procedure adopted from the SAE, 
and corrects the description of test procedures 
used to evaluate brake fluid stroking properties. 

EFFECTIVE DATE: Due to the commercial 
unavailability of RM-1 fluid, this rule is effective 
May 6, 1986. However, because the agency is con- 
cerned that manufacturers who might still be using 
RM-1 fluid to test their products should be able to 
use their existing supplies, use of RM-1 fluid may 
continue until November 3, 1986. 



SUPPLEMENTARY INFORMATION: Federal Motor 
Vehicle Safety Standard (FMVSS) No. 116, Motor 
Vehicle Brake Fluids, and FMVSS No. 106, Brake 
Hoses, specify performance requirements for 
motor vehicle brake fluids and brake hoses. 
Included in the performance requirements of 
Standard No. 106 is a brake fluid compatibility 
test, and included in Standard No. 116 are com- 
patibility, chemical stability, and humidification 
tests. Referee materials are used to test specimens 
of brake hose and brake fluid for compliance with 
the standards' requirements. These materials pro- 
vide a basis of comparison between the results of 
the tests and the specifications of the standards. 
The procedures for the compatibility, chemical sta- 
bility, and humidification tests currently reference 
the referee material brake fluid specified by the 
Society of Automotive Engineers (SAE) in the 
April 1968 version of SAE Standard J 1703b. Stan- 
dard J1703b, in turn, references a referee material 
(RM) identified as RM-1. (Standard No. 116's 
description of SAE Standard J1703b, "Motor 
Vehicle Brake Fluid," April 1968, is incorrect in 
that the correct reference should be to J 1703b, Ju- 
ly 1970. In 1970, the agency proposed to reference 
test procedures of J1703a, April 1968, in Standard 
No. 116. Subsequently, NHTSA changed reference 
from J1703a to J1703b. The effort to make this 
change inadvertently resulted in showing April 
1968, the date of J1703a, as the date of J1703b. 
This notice corrects the error by referencing 
J1703b, July 1970.) 

This rule amends FMVSS Nos. 116 and 106 to 
revise the referee materials and test procedures 
referenced in portions of those standards. The 
SAE, in its January 1980 and November 1983 revi- 
sions of Standard J1703, "Motor Vehicle Brake 
Fluid," substituted a new referee material, 
RM-66-03, in place of RM-1 for use in the J1703 



PART 571; S 106-PRE 53 



compatibility test. This notice adopts this revision 
and references RM-66-03 for use in the compati- 
bility test of Standard No. 106, and the compatibil- 
ity and fluid chemical stability tests of Standard 
No. 116. This notice also references a new referee 
material, TEGME, in the humidification pro- 
cedures of Standard No. 116, adjusts the water 
content level and test temperature referenced in 
the test procedures, and amends the number of 
sets of stroking test materials in the stroking test 
of Standard No. 116. This notice also adopts SAE 
revisions to FMVSS No. 116's humidification test 
which had been inadvertently omitted from the 
amendatory language of the proposed rule, and 
corrects the description of test procedures used to 
evaluate brake fluid stroking properties. 

Testing Brake Hose/Fluid Characteristics 

Brake fluid compatibility is an important factor 
in establishing brake hose life and strength 
characterisitcs. The compatibility test of FMVSS 
No. 106 measures hydraulic brake hose com- 
patibility with brake fluid. The brake hose test 
specimen is filled with the SAE Compatibility 
Fluid for a required number of hours at specified 
temperatures, and is then subjected to constriction 
and burst strength tests. Currently, RM-1 fluid is 
referenced in the test procedures for the 
standard's brake fluid compatibility test. 

Under the compatibility requirements of FMVSS 
No. 116, the compatibiltiy of a brake fluid with an 
RM fluid is determined. The compatibility fluid 
that is used in these tests as a referee material 
should be representative of the fluids found in a 
braking system in service. The tests measure the 
compatibility of fluids of different chemical bases 
by checking whether there are undesirable 
chemical interactions resulting from the mixture of 
fluids. Paragraph S6.10 sets out the procedures for 
evaluating the compatibility of a brake fluid with 
other hquids used in a hydraulic brake system (i.e., 
other brake fluids). This section currently 
references RM-1 fluid as the referee material used 
in that test procedure. 

The humidification tests of FMVSS No. 116 
measure the amount of water absorbed by a brake 
fluid as compared to a reference fluid. The 
presence of water in a brake system degrades 
braking performance and safety by lowering the 
boiling point of brake fluid, increasing the possi- 



bility of vapor lock and the corroding of system 
components, and the depositing of sediment in 
wheel cylinders that could cause a system malfunc- 
tion. 

Standard No. 116 establishes minimum wet 
equilibrium reflux boiling points (ERBP's) for dif- 
ferent grades of brake fluid, and the test pro- 
cedures of S6.2 determine the water content and 
wet ERBP of brake fluid specimens. The current 
test procedure specifies that sample fluids of RM-1 
and the test specimen are to be humidified 
simultaneously under controlled conditions. The 
SAE RM-1 fluid is used as the reference fluid that 
establishes the "endpoint" for humidification. 
When the water content of the RM-1 fluid is 
measured to be 3.50 ± 0.05 percent by weight, the 
test fluid sample is removed from the humidifica- 
tion apparatus. After humidification, the water 
and ERBP of the sample are determined. 

Section 7.2 of FMVSS No. 116 also refers to 
RM-1 fluid as a reference for measuring r,he water 
content of brake fluids. 

RM-66-03 Fluid 

A notice of proposed rulemaking (NPRM) on this 
rulemaking action was published on March 7, 1985 
(50 FR 9294). The NPRM explained that FMVSS 
Nos. 106 and 116 currently reference SAE RM-1 
Compatibility Fluid in their test procedures. In 
that notice, the agency announced its tentative 
finding that the inclusion of RM-1 fluid is no longer 
desirable for the following reasons. 

The agency stated its belief that reference to 
RM-1 fluid should be changed because manufac- 
ture of the fluid has ceased. A new fluid, identified 
as RM-66-03 Compatibility Fluid, has replaced the 
RM-1 fluid in test procedures described in the 
January 1980 and November 1983 revisions of 
SAE Standard J1703. This new fluid is described 
by the SAE as a blend of four proprietary 
polyglycol brake fluids of fixed composition, in 
equal parts by volume. The four fluids selected 
comprise three factory-fill and one after-market 
fluid as follows: DOW HD50-4, DOW 455, Delco 
Supreme II, and Olin HDS-79. 

While RM-1 fluid is not readily available, 
RM-66-03 fluid is available from the SAE in the 
blend and formulation developed by the SAE for 
J1703. The indiviual manufacturers of the four pro- 
prietary fluids have indicated to the SAE Brake 



PART 571; S 106-PRE 54 



Fluids Subcommittee and Reference Materials 
Subcommittee that the proprietary formulation 
might be changed in the commercial market, but 
that the formulations developed for the RM-66-03 
fluid would be guaranteed to be available for a 
minimum five-year period commencing May 1983, 
i.e., at least until May 1988. 

The updated reference to RM-66-03 fluid by the 
SAE is a result of the termination of the manufac- 
turing of the RM-1 fluid. Several of the ingredients 
contained in the RM-1 fluid are not available to 
fluid manufacturers since the materials are no 
longer used in today's fluids, or have become pro- 
hibitively costly to obtain. As a result, manufac- 
turers are unwilling to produce more RM-1 fluid. 

In addition, RM-1 fluid is not representative of 
fluids in service today. The agency stated its belief 
that revising the referee material used in the com- 
patibility test is warranted since the purposes of 
that test would be better served by a referee 
material more representative of today's fluids. In- 
clusion of RM-1 fluid in FMVSS Nos. 116 and 106 
is also undesirable because RM-1 fluid contains tox- 
ic materials which require elaborate protective 
procedures and special handling and manufactur- 
ing processes. 

In consideration of the foregoing, NHTSA pro- 
posed an amendment to FMVSS Nos. 106 and 116 
to substitute new referee materials for the com- 
patibility and humidification tests. For Standard 
No. 106's compatibility requirement and test pro- 
cedures (S5.3.9 and S6.7), and Standard No. 116's 
compatibiHty (6.10), fluid chemical stability (6.5), 
and water content (7.2) tests, the new referee 
material was proposed to be RM-66-03 fluid as 
described in the January 1980 version of SAE 
Standard J1703. 

Seven commenters responded to the NPRM. 
Each commenter agreed with the proposal to 
reference RM-66-03 fluid in FMVSS Nos. 106 and 
116. General Motors Corporation (GM) and 
Chrysler Corporation agreed with the agency's 
tentative conclusion that the new referee material 
would be more available and compatible with cur- 
rent brake fluids than RM-1 fluid. Other com- 
menters believed that the change would be 
practical and reasonable. 

NHTSA has considered the comments to the 
NPRM and has decided to amend FMVSS Nos. 106 
and 116 to reference RM-66-03 compatibility fluid. 



One slight change has been made to the NPRM's 
proposal. The NPRM proposed to reference the 
RM-66-03 fluid as described in the January 1980 
revision of SAE Standard J1703. This rule will 
reference RM-66-03 fluid as described in the 
November 1983 revision of J1703. The two SAE 
revisions of J 1703 are identical in their descrip- 
tions of RM-66-03; the agency is making this 
change in order to keep FMVSS Nos. 106 and 116 
current by referencing the more recent SAE 
standard. 

Use of the RM-66-03 fluid in the test procedures 
of Standards Nos. 116 and 106 should have a 
beneficial impact on safety. Since the RM-1 com- 
patibility fluid currently referenced in FMVSS 
Nos. 106 and 116 is not commercially available, 
ascertaining whether hoses and fluids comply with 
certain requirements related to compatibility and 
boiling points is difficult. Amending the standards 
to allow the use of RM-66-03 fluid in place of RM-1 
provides a readily available compatibility fluid for 
the compliance tests which is more representative 
of fluids used in today's vehicles. 

TEGME, Brake Fluid Grade 

In humidification test procedures under FMVSS 
No. 116, the referee material fluid is used as a 
reference to determine when to terminate the 
humidification procedure. Currently, RM-1 fluid is 
used as this referee material. NHTSA proposed to 
amend Standard No. 116 to reference a new 
referee fluid, triethylene glycol monomethyl ether 
(TEGME), brake fluid grade, as the referee 
material noted in Standard No. 116's procedures 
for a brake fluid's wet equilibrium reflux boiling 
point (S6.2). TEGME has been referenced by the 
SAE in J1703, January 1980, and J1703, 
November 1983, as the referee material used in the 
humidification test procedure. 

In addition to referencing the TEGME material, 
the agency also proposed to amend S6.2 of FMVSS 
No. 116 to adjust the final water content of the 
referee material fluid to 3.70% water (instead of 
the current requirement of 3.5%), change the test 
temperature to 50°C. (from 23°C.), and add a cool- 
ing period for the sealed jar sample. As explained 
in the NPRM, those changes (use of TEGME fluid, 
change in water pickup and test temperature, and 
the cool-down to room temperature) were pro- 
posed as part of the overall changes adopted from 
SAE J1703 procedures. 



PART 571; S 106-PRE 55 



All but one of the commenters to the notice sup- 
ported the changes to the TEGME fluid. Com- 
menters believed that the changes would simplify 
the test procedures and make them more cost 
effective. 

In its comment on the NPRM, Union Carbide 
questioned whether there are adequate data to 
show that the new humidification test procedure 
will produce comparable test results when applied 
to DOT-4 and DOT-5 brake fluids. That commenter 
suggested that NHTSA reconsider adopting the 
SAE J1703, January 1980 humidification test 
method or adopt it as an alternative to the current 
method that uses RM-1 fluid until complete com- 
parative testing could be performed. 

The agency does not agree with Union Carbide 
that the humidification test method of SAE J1703, 
January 1980 should not be adopted as the new 
Standard No. 116 test procedure. The TEGME 
fluid is capable of absorbing a measurable amount 
of water in a given time and is only used as a 
reference to determine when to terminate the 
humidification process. Under the humidification 
test procedure, samples of brake fluid and TEGME 
are humidified simultaneously until a measured 
quantity of fluid is picked up in the TEGME. When 
the water content of the TEGME fluid reaches 3.7 
percent, the brake fluid test specimens are re- 
moved from the test apparatus and their water 
contents and ERBP's are measured. TEGME, the 
referee material used in the humidification pro- 
cedure, thus serves only to establish the end point 
of a test procedure. 

The 3.7 percent TEGME water pickup (at 50°C) 
corresponds to the 3.5 percent water pickup (at 
23 °C) of the referee fluid (RM-1) used previously to 
determine the end point of the humidification pro- 
cedure. The agency has determined that DOT-3 
fluid picks up the same amount of water when 
humidified under procedures which use TEGME as 
the referee material as it does when humidified 
under procedures using RM-1. Therefore, the 
agency believes that the water pickup of test 
fluids, including DOT-4 and DOT-5 fluids, would 
not be affected by the change to TEGME. Ac- 
cordingly, NHTSA is amending FMVSS No. 116 to 
reference the TEGME referee material. 

The NPRM proposed to reference the TEGME 
fluid as described in the January 1980 revision of 
Standard J1703. This rule will instead reference 



TEGME as described in the November 1983 
revision of J1703. The two SAE revisions of J1703 
are identical in their descriptions of TEGME; the 
agency is making this change in order to keep 
FMVSS No. 116 current by referencing the more 
recent SAE standard. 

Humidification Test Procedures 

All commenters supported the additional 
changes to the humidification procedure of S6.2 
adopted from SAE Standard J 1703. This rule 
adopts the proposed changes to S6.2 and adjusts 
the final water content of the referee material fluid 
to 3.70%, changes the test temperature to 50°C, 
and adds a cooling period for the sealed jar sample. 

Other changes to the humidification procedure 
were suggested in the comments to the NPRM. 
GM and Union Carbide Corporation pointed out 
that while NHTSA proposed to adopt the 
humidification test procedures from SAE J1703, 
the procedural modifications proposed in the 
amendatory language differed slightly from the 
SAE standard. GM suggested changing FMVSS 
No. 116's humidification procedure to agree with 
that of SAE J1703, January 1980 in order to 
facilitate testing. The following changes were sug- 
gested: S6.2.1 should be revised to require 150 ml. 
samples of brake fluid and TEGME instead of the 
proposed 100 ml. samples; S6.2.3 should be revised 
to eliminate ammonium sulfate from the list of 
reagents and materials and to specify distilled 
water and TEGME; S6.2.4 should be revised to 
load the dessicators with 450 ml. of distilled water 
instead of the ammonium sulfate /distilled water 
slurry; and S6.2.5 should be revised to use 150 ml. 
samples of the brake fluid and TEGME instead of 
the proposed 100 ml. samples. 

As evidenced by the GM and Union Carbide com- 
ments, it was clear that the agency intended to 
facilitate testing by adopting the overall changes 
to the humidification test from SAE J1703. 
Therefore, NHTSA agrees that those additional 
changes should be incorporated into this final rule. 
This rule amends S6.2.1, S6.2.3, S6.2.4 and S6.2.5 
to correct the minor omissions noted above. Fur- 
ther, S6.2.2 is revised to clarify that distilled water 
would be substituted for the salt slurry in Figure 3 
of FMVSS No. 116, Humidification Apparatus, 
when TEGME is used as the referee material. 



PART 571; S 106-PRE 56 



stroking Test 

The stroking test in FMVSS No. 116 checks the 
lubricity effect of a brake fluid on rubber com- 
ponents. The NPRM explained that the SAE had 
determined, in its revision of J1703, January 1980, 
that three sets of test material are sufficient to 
analyze the adequacy of test results. The notice an- 
nounced that, based on NHTSA's tentative agree- 
ment with that SAE conclusion and its belief that 
compliance testing costs would be reduced by that 
change without an adverse affect on safety, the 
agency was proposing to amend the requirements 
of S5.1.13 and S6.13 to require testing of only 
three sets of test material (consisting of wheel 
cylinders, drums, shoe assemblies, etc.) instead of 
four sets, and eight new brake cups instead of 10. 
Since NHTSA proposed to reduce the number of 
cups tested, a reduction in the number of cups 
checked for unsatisfactory operating condition was 
also proposed. 

All comments supported the agency's proposal 
to revise the stroking test procedures. The com- 
menters believed that the changes proposed in the 
NPRM would simplify the test procedures and 
make them more cost effective. NHTSA agrees, 
and has revised S5.1.13 and S6.13 as proposed in 
the NPRM. 

In addition, this rule makes several changes to 
the stroking test procedures in FMVSS No. 116 
which directly relate to the agency's adoption of 
the SAE stroking test revision. Currently, S6.13.2 
describes the apparatus and equipment used for 
the stroking test and refers to figures in SAE 
Standard J 1703b which depict stroking ap- 
paratuses. Figure 1 of J1703b depicts four sets of 
drum and shoe assemblies. Since NHTSA has 
reduced the number of sets of test materials to 
three, the agency believes that the description of 
the test apparatuses and arrangement of test 
materials should also be revised to reflect this 
change. The description of the apparatuses used in 
the stroking test is changed only to clarify that 
three sets of materials are used, instead of four. 

The following related revisions to the stroking 
test procedure are necessary to facilitate the 
change to three sets of materials. Paragraph 
S6. 13.4(c) describes the preparation and assembly 
of test apparatuses. When a shoe and drum type 
apparatus is used, S6. 13.4(c) specifies a 23 mm. 
stroke length, based on output piston movement of 



four sets of wheel cylinders. Stroke length refers 
to the distance traveled by the master cylinder 
piston to displace a certain volume of fluid in the 
test system which, in turn, forces the wheel 
cylinder pistons to travel a specified distance. 
Since the stroking test is revised to require only 
three sets of materials, the stroke length of the 
master cylinder would no longer be 23 mm. 

This rule deletes reference in S6. 13.4(c) to exact 
piston displacement measurements and a 23 mm. 
stroke length. The agency has determined that it is 
not necessary to specify master cylinder and wheel 
cylinder piston travel since those values are deter- 
mined by the characteristics of the system which 
are specified in the standard (i.e., dimensions of 
the master cyhnder and wheel cylinders, and 
pressure). The stroking test apparatus is a closed 
hydraulic system; pressure of 1000 pounds per 
square inch (psi) is generated at the outlet port of 
the master cylinder, and all pistons have the same 
diameters of IVg inch. Given the above, displace- 
ment of the wheel cylinders is directly proportional 
to the displacement of the master cylinder, and in 
the given test apparatus the stroke length of the 
master cylinder is dependent on system pressure. 
Stroke length would therefore be adjusted by the 
characteristics of the system from the former 
value of 23 mm. to a value proportioned for three 
wheel cylinders. 

Since the agency is eliminating exact wheel 
cylinder piston travel measurements and is speci- 
fying that only three sets of test materials are re- 
quired in the stroking test, this rule also deletes 
reference in S6. 13. 4(c) to Figure 4 of SAE 
Standard J1703b. That figure illustrated the ap- 
proximate pressure buildup versus the master 
cylinder piston movement, and was based on the 
use of four sets of materials. S6. 13.4(c) would con- 
tinue, however, to specify that the pressure 
buildup is relatively low during the first part of the 
stroke, in order to avoid damage of the master 
cyhnder's primary cup by ensuring that the 
primary cup passes the compensating port at a 
relatively low pressure. 

Typographical Errors 

This notice corrects the typographical errors in 
S5. 1.9(a), S5. 1.9(b) and S5.1.12 of Standard No. 
116, as proposed in the NPRM. 



PART 571; S 106-PRE 57 



Effective Date 

This rule is effective May 6, 1986. As explained 
in tlie NPRM, the agency finds good cause for this 
expedited effective date because the RM-1 fluid 
used in the testing procedures of FMVSS Nos. 116 
and 106 is commercially unavailable. Use of the 
RM-66-03 fluid will facilitate compliance testing by 
utilizing a referee material that is currently 
available and more representative of fluids in 
service. However, because the agency is concerned 
that manufacturers who might still be using RM-1 
fluid to test their products should be able to use 
their existing supplies, use of RM-1 fluid may con- 
tinue until October 26, 1986, i.e., 180 days after 
publication of this rule. 

In accordance with the above provision permit- 
ting the use of RM-1 during the interim period, this 
rule describes separate test procedures ap- 
propriate for use with RM-1 and for the new 
referee materials (i.e., RM-6603 and TEGME). 
Test procedures for RM-1 usage are specified for 
those manufacturers who choose to use that fluid 
during the 180-day period. 

Economic Effects 

NHTSA has concluded that this final rule does 
not qualify as a "major rule" within the meaning of 
Executive Order 12291, and that it is not "signifi- 
cant" within the meaning of the Department of 
Transportation's regulatory procedures. Prepara- 
tion of a regulatory impact analysis is not 
necessary for this rulemaking. The agency has 
determined further that the effects of this 
rulemaking are minor and that a full regulatory 
evaluation is not warranted. The rule references 
referee materials in Standards Nos. 116 and 106 
that are readily available to manufacturers of 
brake fluids and brake hoses. 

The agency believes that manufacturers will 
benefit by the change to RM-66-03 fluid and 
TEGME fluid in FMVSS No. 116 and RM-66-03 
fluid in FMVSS No. 106. The fluids are readily 
available whereas RM-1 is not, and are more 
representative of fluids in service today. The 
agency knows of no problems resulting from tests 
onducted with the RM-66-03 and TEGME fluids. 

Some cost savings would be realized with this 
amendment. The utilization of RM-66-03 fluid will 
reduce the costs of fluids used in compliance 
testing without sacrificing adequate test results. 
For example, as cited in the NPRM, when last 



available, RM-1 fluid cost approximately $27.00 
per quart. The cost of RM-66-03 fluid is approx- 
imately $8.00 per quart. 

Cost savings will be realized by the use of the 
TEGME fluid in the humidification tests of 
FMVSS No. 116. The TEGME fluid costs approx- 
imately $3.30 per quart. Further, using the 
TEGME fluid in compliance testing would con- 
serve the more expensive supply of RM-66-03 
brake fluid material. 

The change in the stroking test procedures will 
also result in some cost savings. The costs related 
to the quantities of materials tested will be reduced 
about 25 percent. 

Any changes to Standard Nos. 106 and 116 
referencing the RM-66-03 and TEGME fluids and 
reducing the number of test materials used in the 
stroking test will not significantly affect manufac- 
turers of brake hoses and referee materials. These 
manufacturers may benefit from some cost savings 
resulting from the changes to the standards, but 
will not otherwise be significantly affected by this 
amendment. 

In consideration of the foregoing, 49 CFR 
571.06, Brake Hoses, is amended as follows: 

1. S5.3.9 is revised to read as follows: 

S5.3.9 Brake Fluid Compatibility, Construc- 
tion, and Burst Stength. Except for brake hose 
assemblies designed for use with mineral or 
petroleum-based brake fluids, a hydraulic brake 
hose assembly shall meet the constriction require- 
ment of S5.3.1 after having been subjected to a 
temperature of 200°F for 70 hours while filled with 
SAE RM-66-03 CompatibiHty Fluid, as described in 
Appendix A of SAE Standard J1703, November 
1983, "Motor Vehicle Brake Fluid," November 
1983 (S6.7). It shall then withstand water pressure 
of 4,000 psi for 2 minutes and thereafter shall not 
rupture at less than 5,000 psi (S6.2). (SAE RM-1 
Compatibility Fluid, as described in Appendix A of 
SAE Standard J1703b, "Motor Vehicle Brake 
Fluid," July 1970, may be used in place of SAE 
RM-66-03 until November 3, 1986. 

2. Paragraph S6.7.1(a) is revised to read as 
follows: 

S6.7.1 Preparation. 

(a) Attach a hose assembly below a 1-pint reser- 
voir filled with 100 ml of SAE RM-66-03 Com- 
patibility Fluid as shown in Figure 2. (SAE RM-1 



PART 571; S 106-PRE 58 



Compatibility Fluid, as described in Appendix A of 
SAE Standard J1703b, "Motor Vehicle Brake 
Fluid," July 1970, may be used in place of SAE 
RM-66-03 until October 26, 1986. 

* If * * ^ i4c 

§571.116 [Amended] 

In consideration of the foregoing, 49 CFR 
571.116, Motor Vehicle Brake Fluids, is amended 
as follows: 

1. S5.1.9 is revised to read as follows: 
S5.1.9 Water Tolerance. 

(a) At low temperature. When brake fluid is 
tested according to S6.9.3(a)— 

(1) * * * 

(b) At 60°C (140°F). When brake fluid is tested 
according to S6.9.3(b)— 

/I \ * * * 

2. S5.1.12 is revised to read as follows: 

85. 1.12 Effects on cups. When brake cups are 
subjected to brake fluid in accordance with S6.12— 

****** 

3. S5.1.13 is revised to read as follows: 

55.1.13 Stroking properties. When brake fluid is 
tested according to S6.13— 

****** 

(c) The average decrease in hardness of seven of 
the eight cups tested (six wheel cylinder and one 
master cylinder primary) shall not exceed 15 
IRHD. Not more than one of the seven cups shall 
have a decrease in hardness greater than 17 IRHD; 

(d) None of the eight cups shall be in an un- 
satisfactory operating condition as evidenced by 
stickiness, scuffing, blisters, cracking, chipping, or 
other change in shape from its original 
appearance; 

(e) None of the eight cups shall show an increase 
in base diameter greater than 0.90 mm (0.035 
inch): 

(f) The average lip diameter set of the eight cups 
shall not be greater than 65 percent: 

****** 

4. S6 is revised to read as follows: 

SB. Test procedures. Until October 26, 1986, 
SAE RM-1 Compatibility Fluid, as described in 
Appendix A of SA