[Federal Register Volume 60, Number 141 (Monday, July 24, 1995)]
[Rules and Regulations]
[Pages 37844-37848]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 95-18106]



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DEPARTMENT OF TRANSPORTATION
49 CFR Part 571

[Docket No. 85-06; Notice 9]
RIN 2127-AF82


Federal Motor Vehicle Safety Standards, Passenger Car Brake 
Systems

AGENCY: National Highway Traffic Safety Administration (NHTSA), 
Department of Transportation (DOT).

ACTION: Final rule; Response to petitions for reconsideration.

-----------------------------------------------------------------------

SUMMARY: In February 1995, NHTSA published a new Federal Motor Vehicle 
Safety Standard No. 135, Passenger Car Brake Systems, which replaces 
the existing Standard No. 105, Hydraulic Brake Systems, as it applies 
to passenger cars. The agency's action was part of its efforts to 
harmonize its standards with international standards. The agency 
received three petitions for reconsideration, each of which supported 
the new standard, but recommended one or more changes. This document 
provides NHTSA's response to those petitions. As part of its response, 
the agency is making several minor changes in the standard's test 
conditions. NHTSA is also making a number of correcting amendments to 
the new standard.

DATES: Effective date. The amendments made by this rule are effective 
August 23, 1995.
    Petitions for reconsideration. Petitions for reconsideration must 
be received not later than August 23, 1995.

ADDRESSES: Petitions for reconsideration should be submitted to: 
Administrator, National Highway Traffic Safety Administration, 400 
Seventh Street SW., Washington, DC 20590.

FOR FURTHER INFORMATION CONTACT: Ms. Terri Droneburg, Office of Vehicle 
Safety Standards, National Highway Traffic Safety Administration, 400 
Seventh Street SW., Room 5307, Washington, DC 20590. Phone: (202) 366-
6617. Fax: (202) 366-4329.

SUPPLEMENTARY INFORMATION: On February 2, 1995, NHTSA published in the 
Federal Register (60 FR 6411) a final rule establishing Federal Motor 
Vehicle Safety Standard No. 135, Passenger Car Brake Systems. That 
standard will replace Standard No. 105, Hydraulic Brake Systems, as it 
applies to passenger cars.
    NHTSA received petitions for reconsideration from General Motors 
(GM), the Japan Automobile Manufacturers Association (JAMA), and 
Mercedes-Benz. Each of the petitioners supported the establishment of 
the new standard, but identified one or more areas where they 
recommended changes. The issues raised by the petitioners are addressed 
below.
    GM first identified several technical corrections to make in the 
text of Standard No. 135. NHTSA concurs with these corrections and has 
also identified several other corrections that need to be made. In this 
document, the agency is making those corrections.
    GM next identified one substantive area of concern, involving the 
pedal force constraints for the hot and recovery performance tests 
(S7.14.3(c) and S7.16.3(c)). GM stated that NHTSA had explained in the 
final rule that Standard No. 135 is intended to ensure that faded 
brakes are capable of achieving both a minimum level of performance 
relative to cold effectiveness (i.e., at least 60 percent of cold 
effectiveness deceleration) and a minimum absolute level of performance 
(i.e., stopping distance less than or equal to 89 meters, from a speed 
of 100 km/h (62.1 mph)).
    GM stated that, to make the relative performance a true comparison, 
it is necessary to constrain the hot stop pedal force to that which was 
used during the cold effectiveness stop. GM stated also that only by 
having similar pedal force profiles between the hot and cold stops is 
it possible to effectively compare hot and cold brake performance. That 
company cited the agency's statement in the final rule preamble that, 
``(i)n order for that comparison to be meaningful, the test conditions 
for the two tests should be as close to identical as possible.''
    GM argued, however, that the language adopted in the final rule 
does not facilitate test conditions for the cold and hot stops that are 
as close to identical as possible. GM said that the language instead 
precludes a legitimate comparison between hot and cold performance by 
forcing a significantly different pedal force on the hot stop. GM 
stated that a typical pedal force profile used during cold 
effectiveness testing shows an initial spike, followed by a lower, 
level force. That company stated that because the language of the final 
rule limits the peak hot stop pedal force to the average  cold 
effectiveness pedal force, it precludes the use of an initial spike for 
the comparison hot stop. GM stated that this shortcoming can be easily 
corrected by amending the regulatory language to state that the 

[[Page 37845]]
average hot stop pedal force cannot exceed the average cold 
effectiveness pedal force. GM also stated that the same analysis 
applies to the pedal force constraint for recovery performance.
    NHTSA has evaluated GM's arguments and agrees that the suggested 
changes would make the test conditions for the cold, hot, and recovery 
stops more similar and thereby make the results more comparable. The 
agency is therefore adopting those suggested amendments.
    GM also identified three areas for potential future rulemaking 
concerning Standard No. 135. First, that company stated that, even if 
the agency adopts its recommended changes concerning pedal force, two 
minor flaws will remain with the thermal test protocols. GM stated:

    First, a considerable amount of testing is performed between the 
cold effectiveness test (which serves as the baseline for thermal 
performance) and the thermal tests. These intervening tests can 
introduce distortions to the hot versus cold comparisons by virtue 
of brake and tire conditioning, changing environmental conditions, 
etc. Second, the pedal force spike input during the cold 
effectiveness test may be difficult to precisely replicate in the 
subsequent thermal tests. These two flaws could be corrected by 
adopting constant pedal force cold stops at the onset of the thermal 
test sequence to be used as the baseline comparison stops. The 
preamble to Notice 8 implies that the agency will not take action in 
this area until U.S. and European manufacturers come forward with a 
recommendation. GM requests that the agency initiate this process 
with either a Request for Comments or Advance Notice of Proposed 
Rulemaking.

    While NHTSA has considered this request of GM, the agency does not 
believe that further rulemaking on this particular issue is warranted 
at this time. The agency notes that different manufacturers have 
significantly different views on this issue and that while GM believes 
it is an area where Standard No. 135 could be improved, that company 
has not provided information demonstrating that the current procedure 
creates any significant problems, e.g., compliance difficulties, effect 
on safety, etc. The agency also believes that the issue is only 
relevant for vehicles that do not have ABS. Since it is expected that 
nearly all passenger cars will soon have ABS, the issue will 
essentially become moot.
    GM also noted that NHTSA is conducting rulemaking to amend 
Standards No. 105 and 135 to ensure their appropriateness for electric 
vehicles and electric brakes, and urged the agency to move as quickly 
as possible in this area. NHTSA notes that it is in the process of 
completing a new notice on that subject and expects to issue it 
shortly.
    GM also recommended that the agency initiate rulemaking to extend 
Standard No. 135 to all hydraulically braked vehicles. The agency notes 
that it plans to conduct rulemaking to extend the standard to all 
vehicles with a GVWR of 10,000 pounds or less.
    JAMA petitioned NHTSA to change the temperature range specified for 
initial brake temperature for the cold brake effectiveness test. While 
the final rule specifies a range of 50  deg.C to 100  deg.C, that 
petitioner recommended a range of 65  deg.C to 100  deg.C.
    JAMA noted that its recommended range is similar to that specified 
in Standard No. 105. That organization argued that the wider range 
would impose increased cost burdens since vehicles must meet the 
requirements at all points within the range.
    Upon reconsideration, NHTSA agrees that the lower limit of the 
initial brake temperature should be changed to 65  deg.C. This limit is 
nearly identical to that specified in Standard No. 105. Moreover, while 
some drafts of Regulation 13-H (the proposed harmonized regulation 
developed by the United Nations Economic Commission for Europe) 
included the 50  deg.C value, it was changed to 65  deg. in 1991. Since 
the 65  deg. value is consistent with both Standard No. 105 and the 
most recent draft of Regulation 13-H, and since it results in decreased 
variability in test results, NHTSA believes that this change 
recommended by JAMA should be made.
    JAMA also recommended that the agency amend the definition of 
``initial brake temperature'' to read ``* * * on the hottest brake,'' 
rather than ``* * * on the hottest axle.'' That organization stated 
that this change would eliminate a lack of international harmonization 
without any detriment to motor vehicle safety.
    The agency has decided not to accept this recommendation of JAMA. 
NHTSA believes the initial brake temperature should be based on the 
hottest axle rather than the hottest brake, to ensure that one brake 
does not cause an unrealistically high value for the initial brake 
temperature.
    Mercedes petitioned the agency to change Standard No. 135's 
requirements concerning indication of brake wear status. That company 
noted that the standard specifies that, if a separate indicator is used 
to indicate brake lining wear, the words ``Brake Wear'' must be used. 
Mercedes requested that the agency permit the use of the international 
symbol for brake wear. This symbol consists of a circle, with a dotted 
curved line on each side of the circle. That company argued that there 
are no data indicating a safety need for words versus an international 
symbol. Mercedes also stated that, when marketing a car in nearly 200 
countries, it is highly impractical to use native language text.
    NHTSA notes that Mercedes stated that it and other manufacturers 
can meet the requirements in this area by another alternative permitted 
by Standard No. 135, i.e., providing a means of visually inspecting 
brake pad thickness with the wheels removed. That company asserted 
that, as a result of complying with this alternative, ``(a)n in-dash 
brake wear warning lamp with an international symbol, not Standard 135 
words, can be voluntarily provided, and is, therefore not prohibited by 
Standard 135.'' In support of its position, Mercedes stated that 
``NHTSA's Chief Counsel has reiterated in numerous interpretations 
that, unless specifically prohibited, manufacturers may voluntarily 
provide more features or information than required by a Safety 
Standard.'' The petitioner stated, however, that even with such options 
available, it believes it is important that the final rule be amended 
to permit the international symbol. Among other things, Mercedes stated 
that future electric and hybrid cars may not be able to meet the 
relevant requirements of Standard No. 135 by providing a means of wheel 
removal and inspection, due to weight reduction and other critical 
design conflicts.
    NHTSA has carefully considered Mercedes' request. For reasons 
discussed below, the agency has decided not to make the requested 
change at this time. However, the agency will consider that 
petitioner's request in a separate rulemaking proceeding which will 
more broadly address the use of symbols for brake system indicators.
    The agency will begin its response to Mercedes by addressing that 
company's belief that, so long as a manufacturer provides a means of 
visually inspecting brake pad thickness with the wheels removed (in 
accordance with the alternative specified in S5.1.2(b) of Standard No. 
135), it can voluntarily provide an in-dash brake wear warning lamp 
with an international symbol instead of the words specified by that 
standard. The agency concurs with this result, based on a reading of 
S5.1.2, S5.5.1, and S5.5.5 of Standard No. 135, as well as Standard No. 
101.
    Of particular significance, Standard No. 135's requirement to use 
specified 

[[Page 37846]]
words for a brake wear indicator lamp (S5.5.5(d)(5)) is expressed as 
follows:

    If a separate indicator is provided to indicate brake lining 
wear-out as specified in S5.5.1(d), the words ``Brake Wear'' shall 
be used.

S5.5.1(d), which specifies one of the conditions for which a brake 
indicator must be activated, reads as follows:

    Brake lining wear-out, if the manufacturer has elected to use an 
electrical device to provide an optical warning to meet the 
requirements of S5.1.2(a).

    Since S5.5.5(d)(5)'s wording requirement applies to a separate 
indicator provided to indicate brake lining wear-out ``as specified in 
S5.5.1(d),'' and since S5.5.1(d) only applies where a manufacturer has 
``elected'' to use an electrical device to meet the standard's brake 
wear status requirement, it is NHTSA's interpretation that the wording 
requirement does not apply where a manufacturer has elected options 
other than an electrical device to provide an optical warning. 
Therefore, the agency concurs with the result suggested by Mercedes, 
although not necessarily with the petitioner's stated rationale.
    NHTSA notes that Mercedes is correct that, unless specifically 
prohibited, manufacturers may voluntarily provide more features or 
information than required by a safety standard. The agency cautions, 
however, that this principle, by itself, does not necessarily mean that 
voluntarily provided safety features are not subject to particular 
requirements set forth in a safety standard. Such a result could be 
highly dependent on a specific factual situation and on the specific 
wording of a safety standard. If a manufacturer has a question about 
how a safety standard applies in a specific situation, it may, of 
course, request an interpretation from NHTSA's Chief Counsel.
    NHTSA will now address Mercedes' request that Standard No. 135 be 
amended to permit use of the international symbol for worn brake 
linings instead of the words ``brake wear.'' The agency notes that 
Standard No. 135 specifies the use of words for several brake indicator 
functions, and that the international symbol for worn brake linings is 
part of a family of related symbols which address a number of brake 
functions. Therefore, Mercedes' request is part of a broader issue of 
whether Standard No. 135 should permit the use of symbols instead of 
words for the various brake indicator functions.
    In the preamble to the February 1995 final rule, NHTSA stated:

    Notice 5 and this final rule (Section S5.5.5(a)) allow the use 
of ISO symbols in addition to the required labeling for the purpose 
of clarity. However, the agency has decided not to allow the ISO 
symbol alone to be used as a substitute for the required words. 
NHTSA believes that the ISO symbol can be ambiguous to some drivers 
since the ISO symbol, is not universally understood to represent 
brakes. The agency notes that the commenters did not provide any 
data showing that the ISO brake failure warning indicator is clearly 
understood by drivers in countries in which it is currently in use. 
Moreover, the meaning of the symbol is not readily apparent from its 
appearance, in contrast to some symbols, such as the one for horns, 
whose meaning is understandable on its face. 60 FR 6414, February 2, 
1995.

    NHTSA has decided to conduct a separate proceeding in which it will 
reconsider permitting the use of symbols for brake system indicators. 
The agency believes that, before making any change in this area, 
specific comment should be sought on each of the symbols in question 
and on what steps can be taken to ensure that drivers would learn the 
meaning of the symbols.
    NHTSA is granting the petitions to the extent discussed above; the 
agency is otherwise denying the petitions.
    The agency is making the amendments effective 30 days after 
publication of the final rule. NHTSA finds good cause for such an 
effective date. The amendments do not impose any new requirements or 
make existing requirements more stringent. The amendments instead 
either make corrections in the new standard or very minor changes in 
the test conditions specified by the standard.

Rulemaking Analyses and Notices

Executive Order 12866 (Regulatory Planning and Review) and DOT 
Regulatory Policies and Procedures

    This notice was not reviewed under Executive Order 12866. NHTSA has 
examined the impact of this rulemaking action and determined that it is 
not ``significant'' within the meaning of the Department of 
Transportation's regulatory policies and procedures. NHTSA has further 
determined that the effects of this rulemaking are so minimal that 
preparation of a full regulatory evaluation is not warranted. The 
effects of today's rule are minimal because the rule makes only very 
minor changes in the test conditions specified by Standard No. 135. The 
rule will not have any quantifiable impact on testing costs or vehicle 
costs. The agency's detailed analysis of the economic effects of 
Standard No. 135, set forth in the Final Regulatory Evaluation prepared 
to accompany the February 1995 final rule establishing that standard, 
remains valid.

Regulatory Flexibility Act

    NHTSA has also considered the impacts of this final rule under the 
Regulatory Flexibility Act. I hereby certify that this rule will not 
have a significant economic impact on a substantial number of small 
entities. As explained above, today's final rule makes only very minor 
changes in the test conditions specified by Standard No. 135, and will 
not have any quantifiable impact on testing costs or vehicle costs. For 
these reasons, neither manufacturers of passenger cars, nor small 
businesses, small organizations or small governmental units which 
purchase motor vehicles, will be significantly affected by the rule. 
Accordingly, no regulatory flexibility analysis has been prepared.
Paperwork Reduction Act

    In accordance with the Paperwork Reduction Act of 1980 (P.L. 96-
511), NHTSA notes that there are no requirements for information 
collection associated with this final rule.

National Environmental Policy Act

    NHTSA has also analyzed this final rule under the National 
Environmental Policy Act and determined that it will not have a 
significant impact on the human environment.

Executive Order 12612 (Federalism)

    Finally, NHTSA has analyzed this rule in accordance with the 
principles and criteria contained in E.O. 12612, and has determined 
that this rule will not have significant federalism implications to 
warrant the preparation of a Federalism Assessment.

Civil Justice Reform

    This final rule does not have any retroactive effect. Under 49 
U.S.C. 30103, 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, except to the extent that the State requirement imposes a 
higher level of performance and applies only to vehicles procured for 
the State's use. 49 U.S.C. 30161 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. 

[[Page 37847]]


List of Subjects in 49 CFR Part 571

    Imports, Motor vehicle safety, Motor vehicles, Rubber and rubber 
products, Tires.

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

PART 571--FEDERAL MOTOR VEHICLE SAFETY STANDARDS

    1. The authority citation for Part 571 of Title 49 continues to 
read as follows:

    Authority: 49 U.S.C. 322, 30111, 30115, 30117 and 30166; 
delegation of authority at 49 CFR 1.50.

    2. Section 571.135 is amended by revising S6.1.1, S6.5.3.3, S7, 
S7.1, S7.1.3(a), heading of S7.2.3, S7.2.3(a), S7.2.3(c)(3), S7.2.4(d), 
S7.4.3(a), S7.4.3(e), S7.4.4(b), introductory text of S7.4.4(h), 
S7.4.5, S7.5.2(a), S7.5.2(c), S7.5.3(a), S7.5.3(b), S7.6.2(a), 
S7.6.2(c), S7.6.3, S7.7.3(a), S7.7.3(c), S7.8.2(a), S7.9.2(a), 
introductory text of S7.9.3, S7.10.1, S7.10.3(a), S7.10.3(c), 
S7.10.3(f), introductory text of S7.10.4, S7.11, S7.11.3(a), 
S7.11.3(h), S7.12, S7.12.2(d), S7.13.3(a)(1), S7.13.3(d)(1), 
introductory text of S7.14.3(c), S7.14.3(c)(1), S7.14.3(i), S7.15.3(d), 
S7.16.3(c), and redesignating S6.5.4.3 as S6.5.4.1 and republishing it, 
to read as follows:


Sec. 571.135  Standard No. 135; Passenger car brake systems.

* * * * *
    S6.1.1. Ambient temperature. The ambient temperature is any 
temperature between 0  deg.C (32  deg.F) and 40  deg.C (104  deg.F).
* * * * *
    S6.5.3.3. In the stopping distance formulas given for each 
applicable test (such as S0.10V+0.0060V2), S is the 
maximum stopping distance in meters, and V is the test speed in km/h.
* * * * *
    S6.5.4.1. The vehicle is aligned in the center of the lane at the 
start of each brake application. Steering corrections are permitted 
during each stop.
* * * * *
    S7. Road test procedures and performance requirements. Each vehicle 
shall meet all the applicable requirements of this section, when tested 
according to the conditions and procedures set forth below and in S6, 
in the sequence specified in Table 1:

                      Table 1.--Road Test Sequence                      
------------------------------------------------------------------------
                                                                Section 
                        Testing order                             No.   
------------------------------------------------------------------------
Vehicle loaded to GVWR:                                                 
  1 Burnish..................................................      S7.1 
  2 Wheel lock sequence......................................      S7.2 
Vehicle loaded to LLVW:                                                 
  3 Wheel lock sequence......................................      S7.2 
  4 ABS performance..........................................      S7.3 
  5 Torque wheel.............................................      S7.4 
Vehicle loaded to GVWR:                                                 
  6 Torque wheel.............................................      S7.4 
  7 Cold effectiveness.......................................      S7.5 
  8 High speed effectiveness.................................      S7.6 
  9 Stops with engine off....................................      S7.7 
Vehicle loaded to LLVW:                                                 
  10 Cold effectiveness......................................      S7.5 
  11 High speed effectiveness................................      S7.6 
  12 Failed antilock.........................................      S7.8 
  13 Failed proportioning valve..............................      S7.9 
  14 Hydraulic circuit failure...............................      S7.10
Vehicle loaded to GVWR:                                                 
  15 Hydraulic circuit failure...............................      S7.10
  16 Failed antilock.........................................      S7.8 
  17 Failed proportioning valve..............................      S7.9 
  18 Power brake unit failure................................      S7.11
  19 Parking brake...........................................      S7.12
  20 Heating Snubs...........................................      S7.13
  21 Hot Performance.........................................      S7.14
  22 Brake cooling...........................................      S7.15
  23 Recovery Performance....................................      S7.16
  24 Final Inspection........................................      S7.17
------------------------------------------------------------------------

    S7.1. Burnish.
* * * * *
    S7.1.3. * * *
    (a) IBT: 100  deg.C (212  deg.F).
* * * * *
    S7.2.3. Test Conditions and Procedures.
    (a) IBT: 65  deg.C (149  deg.F), 100  deg.C 
(212  deg.F).
* * * * *
    (c) * * *
    (3) The pedal is released when the second axle locks, or when the 
pedal force reaches 1kN (225 lbs), or 0.1 seconds after first axle 
lockup, whichever occurs first.
* * * * *
    S7.2.4. * * *
    (d) If any one of the three valid runs on any surface results in 
neither axle locking (i.e., only one or no wheels locked on each axle) 
before a pedal force of 1kN (225 lbs) is reached, the vehicle shall be 
tested to the torque wheel procedure.
* * * * *
    S7.4.3. * * *
    (a) IBT: 65  deg.C (149  deg.F), 100  deg.C 
(212  deg.F).
* * * * *
    (e) Number of runs: With the vehicle at LLVW, run five stops from a 
speed of 100 km/h (62.1 mph) and five stops from a speed of 50 km/h 
(31.1 mph), while alternating between the two test speeds after each 
stop. With the vehicle at GVWR, repeat the five stops at each test 
speed while alternating between the two test speeds.
* * * * *
    S7.4.4. * * *
    (b) For each brake application under S7.4.3 determine the slope 
(brake factor) and pressure axis intercept (brake hold-off pressure) of 
the linear least squares equation best describing the measured torque 
output at each braked wheel as a function of measured line pressure 
applied at the same wheel. Only torque output values obtained from data 
collected when the vehicle deceleration is within the range of 0.15g to 
0.80g are used in the regression analysis.
* * * * *
    (h) Plot f1 and f2 obtained in (g) as a function of z, 
for both GVWR and LLVW load conditions. These are the adhesion 
utilization curves for the vehicle, which are compared to the 
performance requirements in S7.4.5. shown graphically in Figure 2:
* * * * *
    S7.4.5. Performance requirements. For all braking ratios between 
0.15 and 0.80, each adhesion utilization curve for a rear axle shall be 
situated below a line defined by z=0.9k where z is the braking ratio 
and k is the PFC.
* * * * *
    S7.5.2. * * *
    (a) IBT: 65  deg.C (149  deg.F), 100  deg.C 
(212  deg.F).
* * * * *
    (c) Pedal force: 65N (14.6 lbs), 500N (112.4 
lbs).
* * * * *
    S7.5.3. * * *
    (a) Stopping distance for 100 km/h test speed: 70m (230 
ft).
    (b) Stopping distance for reduced test speed: 
S0.10V+0.0060V\2\.
* * * * *
    S7.6.2. * * *
    (a) IBT: 65  deg.C (149  deg.F), 100  deg.C 
(212  deg.F).
* * * * *
    (c) Pedal force: 65N (14.6 lbs), 500N (112.4 
lbs).
* * * * *
    S7.6.3. Performance requirements.
    Stopping distance: S0.10V+0.0067V\2\.
* * * * *
    S7.7.3. * * *
    (a) IBT: 65  deg.C (149  deg.F), 100  deg.C 
(212  deg.F).
* * * * *
    (c) Pedal force: 65N (14.6 lbs), 500N (112.4 
lbs).
* * * * *
    S7.8.2. * * *
    (a) IBT: 65  deg.C (149  deg.F), 100  deg.C 
(212  deg.F).
* * * * * 

[[Page 37848]]

    S7.9.2. * * *
    (a) IBT: 65  deg.C (149  deg.F), 100  deg.C 
(212  deg.F).
* * * * *
    S7.9.3. Performance requirements. The service brakes on a vehicle 
equipped with one or more variable brake proportioning systems, in the 
event of any single functional failure in any such system, shall 
continue to operate and shall stop the vehicle as specified in 
S7.9.3(a) or S7.9.3(b).
* * * * *
    S7.10.1. General information. This test is for vehicles 
manufactured with or without a split service brake system.
* * * * *
    S7.10.3. * * *
    (a) IBT: 65  deg.C (149  deg.F), 100  deg.C 
(212  deg.F).
* * * * *
    (c) Pedal force: 65N (14.6 lbs), 500 N (112.4 
lbs).
* * * * *
    (f) 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 common to two or more subsystems.
* * * * *
    S7.10.4. Performance requirements.
    For vehicles manufactured with a split service brake system, in the 
event of any rupture or leakage type of failure in a single subsystem, 
other than a structural failure of a housing that is common to two or 
more subsystems, and after activation of the brake system indicator as 
specified in S5.5.1, the remaining portions of the service brake system 
shall continue to operate and shall stop the vehicle as specified in 
S7.10.4(a) or S7.10.4(b). For vehicles not manufactured with a split 
service brake system, in the event of any one rupture or leakage type 
of failure in any component of the service brake system and after 
activation of the brake system indicator as specified in S5.5.1, the 
vehicle shall by operation of the service brake control stop 10 times 
consecutively as specified in S7.10.4(a) or S7.10.4(b). Each of the 10 
stops shall meet the applicable stopping distance requirement.
* * * * *
    S7.11. Brake power unit or brake power assist unit inoperative 
(System depleted).
* * * * *
    S7.11.3. * * *
    (a) IBT: 65  deg.C (149  deg.F), 100  deg.C 
(212  deg.F).
* * * * *
    (h) If the brake power unit or power assist unit operates in 
conjunction with a backup system and the backup system is automatically 
activated in the event of a primary power service failure, the backup 
system is operative during this test.
* * * * *
    S7.12. Parking brake.
* * * * *
    S7.12.2. * * *
    (d) Parking brake applications: 1 application and up to 2 
reapplications, if necessary.
* * * * *
    S7.13.3. * * *
    (a) * * *
    (1) Establish an IBT before the first brake application (snub) of 
55  deg.C (131  deg.F), 65  deg.C (149  deg.F).
* * * * *
    (d) * * *
    (1) Maintain a constant deceleration rate of 3.0 m/s2 (9.8 
fps2).
* * * * *
    S7.14.3. * * *
    (c) Pedal force:
    (1) The first stop is done with an average pedal force not greater 
than the average pedal force recorded during the shortest GVWR cold 
effectiveness stop.
* * * * *
    (i) Immediately after completion of the second hot performance 
stop, drive 1.5 km (0.93 mi) at 50 km/h (31.1 mph) before the first 
cooling stop.
* * * * *
    S7.15.3. * * *
    (d) Deceleration rate: Maintain a constant deceleration rate of 3.0 
m/s2 (9.8 fps2).
* * * * *
    S7.16.3. * * *
    (c) Pedal force: The average pedal force shall not be greater than 
the average pedal force recorded during the shortest GVWR cold 
effectiveness stop.
* * * * *
    Issued on July 18, 1995.
Ricardo Martinez,
Administrator.
[FR Doc. 95-18106 Filed 7-21-95; 8:45 am]
BILLING CODE 4910-59-P