[Federal Register Volume 62, Number 172 (Friday, September 5, 1997)]
[Rules and Regulations]
[Pages 46907-46919]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-23318]


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DEPARTMENT OF TRANSPORTATION

National Highway Traffic Safety Administration

49 CFR Part 571

[Docket No. 85-6; Notice 12]
RIN 2127-AG05


Federal Motor Vehicle Safety Standards; Hydraulic Brake Systems; 
Passenger Car Brake Systems

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

ACTION: Final rule.

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SUMMARY: This document amends Federal Motor Vehicle Safety Standards 
Nos. 105 Hydraulic Brake Systems and 135 Passenger Car Brake Systems to 
accommodate the brake systems on electric vehicles. The amendments 
address unique characteristics of brake systems on electric vehicles, 
such as regenerative braking, and are intended to assure safe 
performance for those brake systems. The amendments of Standard No. 105 
apply to electric trucks, buses, and multipurpose passenger vehicles. 
They also apply to electric passenger cars that have not availed 
themselves of the option of conforming to Standard No. 135, which is 
mandatory for all passenger cars manufactured on and after September 1, 
2000. The amendments to Standard No. 135 complement those made to 
Standard No. 105.

DATES: The amendments to both standards are effective October 20, 1997. 
Compliance with Standard No. 105 is mandatory as of September 1, 1998.
    Compliance with Standard No. 135 is mandatory as of September 1, 
2000, the effective date of Standard No. 135. Petitions for 
reconsideration of the final rule must be submitted not later than 
October 20, 1997.

ADDRESS: Petitions for reconsideration should be addressed to Docket 
85-6; Notice 12, and submitted to Docket Room, NHTSA, Room 5108, 400 
Seventh St. SW, Washington, DC 20590.

FOR FURTHER INFORMATION CONTACT: Samuel Daniel, Vehicle Dynamics 
Division, Office of Vehicle Safety Standards, NHTSA (Phone: 202-366-
4921).

SUPPLEMENTARY INFORMATION:

Table of Contents

1. Background
2. Issues relating to Definitions
3. Partial failure (Standard No. 105)
4. Issues relating to RBS:
    A. RBS as part of the service brake system
    B. RBS braking effects
    C. ABS control over RBS
5. Issues relating to warning indicators:
    A. Red ``BRAKE'' lamp as signal of RBS failure
    B. Common ABS/RBS malfunction warning indicator
6. Issues related to compliance testing:
    A. Procedure for determining battery state of charge
    B. Procedure for charging batteries during burnish
    C. Procedure for recharging batteries
    D. Testing in gear as opposed to testing in neutral
    E. Testing at low state of charge
7. Issues relating to test conditions:
    A. Initial brake temperature (IBT)
    B. Static parking brake test
    C. Stops with engine off (Standard No. 135)
8. International harmonization
Effective dates
Regulatory analyses:

[[Page 46908]]

    Executive Order 12866 (Regulatory Planning and Review) and DOT 
Regulatory Policies and Procedures
    Regulatory Flexibility Act
    Executive Order 12612 (Federalism)
    National Environmental Policy Act
    Executive Order 12778 (Civil Justice Reform)

1. Background

    On January 15, 1993, NHTSA published a Supplemental Notice of 
Proposed Rulemaking (SNPRM) concerning brake system performance of 
electric vehicles (EVs) (Docket No. 85-6; Notice 7, 58 FR 4649). Notice 
7 proposed amendments to Standard No. 105, Hydraulic Brake Systems and 
revised portions of a proposed Standard No. 135, Passenger Car Brake 
Systems. Standard No. 135 was issued as a final rule (Notice 8, 60 FR 
6411) on February 2, 1995, with an effective date of March 6, 1995. 
Passenger cars, including EVs, may comply with either Standard No. 105 
or Standard No. 135, until September 1, 2000, after which Standard No. 
135 will become the sole Federal motor vehicle safety standard for 
passenger car brakes. Standard No. 105, as amended in this notice, will 
continue to apply to electrically-powered multipurpose vehicles, 
trucks, and buses after September 1, 2000, although NHTSA has proposed 
(Notice 11) that Standard No. 135 be amended to apply, effective 
September 1, 2002, to multipurpose passenger vehicles, trucks, and 
buses with a GVWR of 10,000 pounds or less (61 FR 19602).
    On September 26, 1995, the agency published a Further Supplemental 
Notice of Proposed Rulemaking (FSNPRM), Notice 10 (60 FR 49544). Notice 
10 refined Notice 7's proposed amendments to Standard Nos. 105, 
Hydraulic Brake Systems, and No. 135, Passenger Car Brake Systems. For 
a detailed history of the development of Federal braking standards for 
EVs, the reader may consult Notice 7 and Notice 10.
    Seven commenters, all motor vehicle manufacturers, responded to 
Notice 10. They were Toyota Motor Corporation, General Motors 
Corporation (GM), Chrysler Corporation, Ford Motor Company, Nissan 
North America, Hydro Quebec (HQ), and Honda. All supported the agency's 
rulemaking for EV brake systems. Notice 10 solicited specific comment 
on two general questions: (1) Whether 2 miles is sufficient distance 
for an EV to attain its maximum speed for compliance test purposes, and 
(2) whether any EV manufacturer plans to equip its vehicles with a 
braking system that includes a regenerative braking system (RBS) that 
does not include an anti-lock braking system (ABS). All seven 
commenters indicated that 2 miles was sufficient for an EV to obtain 
maximum speed under most conditions. None of the commenters indicated 
that they planned to produce EV brake systems that included RBS but 
excluded ABS.
    The following were the specific issues raised by comments to Notice 
10.

2. Issues Relating to Definitions

    Notice 10 proposed revising the existing definitions of ``Backup 
system'' and ``Split service brake system'', and adding definitions for 
``Electric vehicle or EV'', and ``Regenerative braking system or RBS.'' 
These would apply to both Standards Nos. 105 and 135. With the minor 
addition noted below for RBS, the four definitions have been adopted as 
proposed.
    In addition, Notice 10 proposed a definition of ``Maximum speed or 
Vmax'' for Standard No. 135. Standard No. 135 now contains a definition 
of the term, thus, this Notice only adds language to the definition 
that is appropriate for EVs. With reference to RBS, HQ suggested that 
the term ``dynamic braking'' be adopted for purposes of Standards Nos. 
105 and 135. Dynamic braking includes vehicle retardation that results 
from dissipation of electrical energy when the battery(s) is at a high 
state of charge as well as the retardation that occurs during battery 
recharging when the battery(s) state of charge is low. HQ suggested 
that the RBS definition proposed in Notice 10 be modified to include 
reference to the dissipation of the energy generated by the propulsion 
motors. The proposed definition stated that the energy produced by the 
propulsion motors in the regenerative mode is returned to the 
battery(s). Dissipation of the electrical energy developed through the 
RBS could develop braking forces that are not dependent on the state-
of-charge of the batteries, according to HQ.
    NHTSA agrees with HQ's observations that dissipation of the energy 
produced by RBS while the propulsion motor(s) are in the regenerative 
mode was not addressed in the proposed RBS definition. Since RBS 
control systems with the capability of dissipating energy generated by 
the RBS are under development, the agency believes that the definition 
of RBS should include a reference to this capability. Thus, NHTSA is 
amending the definition proposed in Notice 10 for regenerative braking 
system (RBS) in Standards Nos. 105 and 135 to state that it ``* * * 
means a system for recovering or dissipating kinetic energy. * * *'' 
However, the agency does not believe a definition for ``dynamic 
braking'' should be added to the braking standards. HQ did not indicate 
how it would be placed at a disadvantage without the new definition. 
The definition for dynamic braking recommended by HQ involves a 
combination of the energy dissipated and stored by the RBS control 
system. The agency feels that inclusion of the energy dissipation 
feature in the definition for RBS is sufficient to address HQ's 
comment.
    Nissan commented on the lack of definition of electrically-actuated 
service brakes'', and asked that the agency adopt one to specify 
electrically-actuated service brake system components. Toyota 
recommended that the agency define the term as ``a braking system which 
converts the electric energy of the battery directly to the braking 
force.'' In its view, it is necessary to distinguish systems whose main 
braking power is electrical from those systems in which electric energy 
is used to operate power assist units such as vacuum and hydraulic 
pumps. Electrically-operated power assist units should not be 
considered electrically-actuated service brakes. Honda also asked for a 
clarification of the term.
    Notice 10 uses the term ``electrically-actuated service brakes'' 
several times in the prospective regulatory text for Standards Nos. 105 
and 135, and, as the commenters noted, without proposing a definition 
for it. One example of use of the term is in proposed paragraphs 
S5.1.3.5 and S7.11.3 of Standards Nos. 105 and 135 respectively, called 
Electric brakes, which specify partial failure performance requirements 
for vehicles with any single failure in the electrically-actuated 
service brakes.
    NHTSA believes that Notice 10 contained an adequate explanation of 
electrically-actuated service brakes, brake power assist units, and 
electric or electronic transmission or service brake control. 
Electrically-driven brake power assist units, such as hydraulic pumps 
or vacuum motors that serve to reduce the driver-applied brake control 
force, are not electrically-actuated service brake components. Neither 
are systems in which the brake control signal is transmitted 
electrically or electronically from the brake control to the foundation 
brake (commonly known as electronic braking systems). The definition of 
``electrically-actuated service brakes'' will read: ``Electrically-
actuated service brakes means service brakes that utilize electrical 
energy to actuate the foundation brakes.''
    HQ requested that the definition of ``antilock brake system'' (ABS) 
in Standards No. 105 and 135 be modified to indicate that ABS is a 
capability of the service brake system. ABS is defined

[[Page 46909]]

in the standards as part of the service brake system rather than a 
capability of the service brake system. HQ also suggested that the 
definition of ``ABS'' be changed by substituting the term ``braking'' 
for ``brake actuating'' because the latter implies the actuation of a 
foundation brake. According to HQ, the term ``braking'' would apply to 
any type of braking force modulation including braking forces generated 
by vehicle components other than the foundation brakes.
    The agency does not concur with these suggested modifications to 
the definition for ``ABS''. It believes that the braking forces 
developed by an electric motor(s) in an EV are covered adequately in 
the definition of ``regenerative braking system.'' Also, most 
conventional braking systems need to have specific hardware added to 
accomplish the ABS function. The agency has concluded that the current 
definition of RBS adequately addresses the braking system design 
features described by HQ.

3. Partial Failure (Standard No. 105)

    Notice 10 proposed adding partial failure provisions to Standard 
No. 105 in a new paragraph S5.1.2.3., that a vehicle ``shall be capable 
of stopping from 60 mph within the corresponding distance specified in 
Column IV of Table II when there is a single failure in an electric 
brake circuit, and with all other systems intact.'' This was supported 
and has been adopted.
    In addition, new wording was proposed under the partial failure 
requirements to address failures of an RBS that is part of the service 
brake system, since the RBS is not a separate ``circuit'' of the 
service brake system. This, too, was supported and has been adopted.

4. Issues Relating to RBS

A. RBS as Part of the Service Brake System

    Notice 10 proposed that RBS would be ``considered to be part of the 
service brake system if it is automatically activated by an application 
of the service brake control, if there is no means provided for the 
driver to disconnect or otherwise deactivate it, and if the vehicle has 
no `neutral' transmission position.''
    GM indicated that the existence of a neutral transmission position 
should not exclude RBS from being considered part of the service brake 
system, according to GM, because a neutral transmission position need 
not have any effect on the operation of an RBS. The ability of the 
driver to disengage the RBS should be the only factor that precludes an 
RBS from being considered part of the service brake system.
    Toyota commented that to its knowledge, almost all EVs with RBS 
have a neutral transmission position, and that the ``no neutral 
transmission position'' criterion should be deleted from conditions 
required for an RBS to be considered part of the service brake system.
    Honda believed that the conditions under which RBS is considered 
part of the service brake system should be modified to indicate that 
the vehicle transmission may have no electrical or mechanical neutral 
position. Honda is concerned that RBS may be designed such that any 
torque from it is canceled when the shift lever is placed in neutral, 
even though there is no mechanical disconnection between the drive 
train and the motor.
    NHTSA agrees with GM and Toyota that the lack of a neutral 
transmission position need not be a condition for inclusion of RBS in 
the service brake system, and is deleting it from the final rule. A 
neutral transmission position need not have an effect on RBS because 
the neutral position does not require that the drive line be 
mechanically disconnected from the propulsion motor(s), as indicated by 
Honda.
    Honda requested that a distinction be made between a neutral 
position that includes mechanical disconnection between the propulsion 
battery(s) and the drive line and one that does not. NHTSA does not 
believe that a definition for ``neutral'', as requested by Honda, is 
needed. However, Notice 10 proposed that including RBS in the service 
brake system requires that the selected position of the vehicle's 
transmission have no effect on the RBS function.
    NHTSA believes that RBS should operate in the same manner and under 
the same conditions as the service brake system if it is to be included 
as part of the service brake system. For example, the service brake 
system is controlled by the service brake control only. If RBS is to be 
included in the service brake system, it should also be controlled by 
the service brake control only. Similarly, the service brake system is 
operational in all transmission positions (gears) and RBS should also 
be operational in all transmission gears, including neutral, if it is 
to be considered part of the service brake system.
    In view of the comments to Notice 10, NHTSA is modifying the 
conditions under which RBS is considered part of the service brake 
system. Accordingly, the final rule amending Standards No. 105 
(S6.2.4(a)) and No. 135 (S5.1.3(a)) states that ``the RBS is considered 
part of the service brake system if it is automatically activated by an 
application of the service brake control, if there is no means provided 
for the driver to disconnect or otherwise deactivate it, and it is 
activated in all transmission positions, including neutral.''

B. RBS Braking Effects

    Nissan believes the retardation capacity of some electric 
propulsion motor(s) is insufficient to be characterized as braking. 
Nissan requests that only RBS that demonstrate braking effects greater 
than the transmission braking effects required in Standard No. 102, 
Transmission shift lever sequence, starter interlock, and transmission 
braking effect, be considered in Standards Nos. 105 and 135.
    NHTSA does not believe RBS systems should be required to have at 
least a two speed transmission, as would be required if the 
transmission braking effects provisions of Standard No. 102 were added 
to the braking standards. It is practical for an EV to perform with a 
single gear ratio transmission. The agency believes that the Nissan 
request would limit EV design unnecessarily. Therefore, it is taking no 
action on this request.

C. ABS Control Over RBS

    Proposed Paragraphs S5.5 of Standard No. 105 and S5.1.3 of Standard 
No. 135 state that ``* * * for an EV that is equipped with both ABS and 
RBS that is part of the service brake system, the ABS must control the 
RBS''.
    Chrysler cautioned that EV technology is still new and 
manufacturers need more design flexibility in this area, and argued 
that it is inappropriate for the agency to require that RBS be 
controlled by ABS and that the agency should specify performance 
requirements.
    The purpose of the proposed requirement is to assure that RBS is 
not operating while ABS is reducing the braking forces in the 
foundation brake system. The added braking torque of the RBS under this 
condition would be counter-productive and may cause vehicle 
instability. NHTSA believes that the requirement is necessary for RBS 
that is part of the service brake system since these systems cannot be 
controlled by the driver. The requirement is adopted as proposed.

[[Page 46910]]

5. Issues Relating to Failure Indicators

A. Red ``BRAKE'' Warning Lamp as Signal of RBS Failure

    Notice 10 proposed new paragraphs in Standards No. 105 (S5.3.1) and 
No. 135 (S5.5.5) which would require that a red ``brake'' indicator 
lamp be illuminated under various conditions including the three 
following: ``(e) For a vehicle with electrically-actuated service 
brakes, failure of the source of power to the brakes, or diminution of 
the state of charge of the batteries to a level less than that 
specified by the manufacturer for the purpose of warning a driver of 
degraded brake performance, (f) For a vehicle with electric 
transmission of the service brake control signal, failure of the brake 
control circuit, and (g) For an EV with RBS that is part of the service 
brake system, failure of the RBS.''
    GM commented that failure of the RBS in all known EV brake systems 
will not cause a significant reduction in overall braking performance. 
Therefore, failure of the RBS should not result in the illumination of 
a red telltale lamp since red telltales are used to indicate emergency 
situations in which the vehicle needs immediate service. An amber 
driver warning display such as the ABS telltale should be allowed in 
the standards as an option to indicate an RBS failure whether or not 
RBS is part of the service brake system.
    According to Ford, failure of RBS will diminish an enhancement of 
the braking system but will not result in substantially reduced braking 
performance. The RBS on-board telltale need not be red, indicating the 
need for immediate service, but an amber lamp, such as the ABS warning 
indicator, should be an option.
    According to GM and Ford, the foundation brake system on their EV 
models is capable of meeting all braking performance requirements 
without contribution from the RBS. As a result, GM and Ford believe 
that a failure of the RBS system should not require the illumination of 
a red ``Brake'' indicator.
    Honda believes that manufacturers should be allowed to use an amber 
indicator lamp instead of a red lamp when a failure occurs in the brake 
control circuit of a vehicle with electric transmission of the service 
brake control signal provided that the total braking force is not 
impaired by the failure. It, too, agrees that, in the event of RBS 
failure or failure of the electrical circuitry that controls the 
hydraulic brake force, all braking would be done by the hydraulic 
system with no loss of performance.
    Honda further states that Standards Nos. 105 and 135 do not require 
illumination of a red brake warning lamp when a brake power unit, power 
assist unit, or an ABS failure occurs.
    In Notice 10, the agency retained the proposed requirement for 
illumination of an on-board, red ``Brake'' lamp to indicate failure of 
these systems. Notice 10 proposed that the requirement for a red brake 
lamp for RBS failures be limited to cases in which RBS is part of the 
service brake system. This was a modification of Notice 7, which 
required that failure of RBS systems that are part of the service brake 
system and those that are not, be indicated by a red on-board brake 
lamp.
    The arguments made by commenters to Notice 10 stating that braking 
performance is not substantially diminished by a failure of the RBS are 
convincing. If RBS is part of the service brake system, it is active at 
all times and is controlled by application of the service brake only. 
The contribution of RBS to overall vehicle braking may be substantial 
at times and this contribution is dependent on many factors including 
the state of charge of the propulsion battery(s). NHTSA agrees with the 
commenters that a failure of RBS will not affect the ability of the 
foundation brakes to provide adequate brake performance under most 
conditions. The agency also agrees with commenters that the loss of the 
RBS braking contribution will not result in a safety hazard in an 
emergency stop situation. The agency accepts the request by GM, Ford 
and Honda to allow an optional amber (yellow) lamp to warn drivers of a 
failed RBS system. NHTSA believes that illumination of the red 
``brake'' warning signal would signify the need for immediate remedial 
action by the driver, which is not warranted. The ``service soon'' 
message that is conveyed by an amber on-board telltale is sufficient 
warning in the case of a failed RBS system that is part of the service 
brake system.
    NHTSA has not granted Honda's request that an amber lamp be allowed 
which would indicate a failure in the electric brake control circuitry 
of a brake system in which the brake control signal is transmitted 
electrically from the service brake control to the foundation brakes 
(paragraph S5.3.1(f) of Standard No. 105, and paragraph S5.5.1(f) of 
Standard No. 135). The final rule allows the option of illuminating an 
amber on-board lamp in the event of an RBS failure for cases in which 
the RBS is part of the service brake system. However, an amber 
indicator lamp will not be allowed as an option to replace a red 
indicator to signal failure of the control circuit for vehicles with 
electric transmission of the brake control signal. See the amended text 
in the discussion under the heading that follows.

B. Common ABS/RBS Malfunction Indicator

    Ford requests that the option be provided to group the RBS and ABS 
malfunction modes with a common warning indicator because the two 
systems share many of the same software and hardware components.
    NHTSA agrees that a common ABS/RBS malfunction warning indicator 
should be allowed for cases in which the RBS is part of the service 
brake system. In these cases, ABS and RBS are required to communicate 
(see proposed paragraph S5.5 of Standard No. 105) and are likely to 
share many components, as indicated by Ford. Accordingly, paragraph 
S5.3.1(g) of Standard No. 105, and paragraph S5.5.1(g) of Standard No. 
135 are adopted to require an indicator to indicate failure of the RBS 
and optional illumination under other circumstances: ``(g) For an EV 
with RBS that is part of the service brake system, failure of the RBS. 
An amber lamp may be used displaying the symbol `RBS'. RBS failure in a 
system that is part of the service brake system may also be indicated 
by an amber lamp that also indicates ABS failure and displays the 
symbol `ABS/RBS'''.

6. Issues Related to Compliance Testing

A. Procedure for Determining Battery State of Charge

    NHTSA proposed that the state of charge of the propulsion batteries 
be determined in accordance with SAE J227a Electric Vehicle Test 
Procedure, February 1976 (S6.2.1 of FMVSS No. 105, S6.3.11.1 of 
Standard No. 135), specifically that the applicable sections of J227a 
are 3.2.1 through 3.2.4, 3.3.1 through 3.3.2.2, 3.4.1 and 3.4.2, 4.2.1, 
5.2, 5.2.1, and 5.3. There were no comments on this issue and the 
proposal has been adopted.

B. Procedure for Recharging Batteries During Burnish

    The burnish procedures (S7.4 of Standard No. 105 and S7.1 of 
Standard No. 135) result in a maximum distance between each of the 
burnish stops of 1.24 miles. The continuous acceleration and 
deceleration of a burnish procedure could result in fairly extensive 
battery depletion after approximately 40 stops. Therefore, NHTSA 
proposed that the propulsion batteries be recharged after each 
increment of 40 burnish stops until each burnish procedure is complete 
(S6.2.2 of Standard No. 105 and

[[Page 46911]]

S6.3.11.2 of Standard No. 135). Charging at a more frequent interval 
would be permitted if the vehicle were incapable of achieving the 
initial burnish test speed during a 40-stop sequence. In addition, the 
manufacturer would be permitted the option of recharging by external 
means or by substituting other propulsion batteries at 95 per cent or 
greater charge. This proposal was supported by the commenters, and is 
adopted in the final rule. Notice 10 also proposed that, if an EV has a 
manual control for setting the level of regenerative braking, at the 
beginning of each burnish procedure the control would be set to provide 
maximum regenerative braking throughout each burnish. There were no 
comments on this proposal, and it is adopted.
    In GM's view, the brake burnishing procedures proposed for S6.2.2 
of Standard No. 105 are not clear with respect to the propulsion 
battery state of charge at the beginning of the tests. GM recommended 
that the final rule be consistent with the burnish procedures adopted 
for Standard No. 135. GM is correct, and paragraph S6.2.2 as adopted 
specifies that the state of charge of the propulsion battery(s) at the 
beginning of each burnish procedure is not less than 95 percent of full 
charge. This modification is also consistent with the burnishing 
requirements and procedures adopted in Standard No. 135.

C. Procedure for Charging Batteries

    Notice 10 proposed that each burnish procedure and each braking 
test procedure be initiated with the EV's propulsion batteries at a 
state of charge of not less than 95 percent. Paragraphs S6.2.2 and 
S6.2.3 of Standard No. 105 and paragraph S6.3.11 of Standard No. 135 
read in part as follows: ``At the beginning of each performance test in 
the test sequence (S7.3, S7.5, S7.7 through S7.11, and S7.14 through 
S7.19 of this standard), unless otherwise specified, an EV's propulsion 
battery(s) are at a state or charge of not less than 95 percent (the 
batteries may be charged by external means or replaced by batteries 
that are at a state of charge of not less than 95 percent)''.
    GM commented that the phrase ``or fully charged per the 
manufacturer's recommended procedure'' should be added to the 
specifications for charging EV batteries. In its view, adding the 
phrase will avoid potential conflicts and ambiguities for cases in 
which the EV charging system is not designed to charge the battery(s) 
to 95 percent of capacity. According to GM, extreme high and low states 
of charge should be avoided to maximize battery life expectancy. GM 
believes the manufacturer's recommended procedure for charging 
batteries may be especially important for hybrid vehicles with on-board 
chargers since these battery(s) may be designed to operate in a narrow 
state of charge range.
    Chrysler stated that all its EVs are equipped with an on-board 
battery management system that controls battery charging, discharging, 
and overall performance. The EV brake testing requirements in the final 
rule should specify that the manufacturer's recommended energy charging 
and measuring procedures be utilized, if available.
    NHTSA agrees that the manufacturer's procedures should be used for 
charging the propulsion batteries for performance tests as well as 
burnishing if such procedures are available.
    The agency is changing the amendments proposed in Notice 10 
requiring that battery(s) be at a state of charge of not less than 95 
percent at the beginning of each test procedure. The state of charge 
requirement is being expanded to allow the battery(s) to be charged in 
accordance with procedures recommended by the vehicle manufacturer. If 
a battery charging procedure or a state of charge measurement procedure 
is permanently attached to the vehicle or published in the vehicle 
operator's manual, the procedure will be utilized during brake testing. 
If the manufacturer does not provide a procedure for charging the 
propulsion battery(s), the procedure proposed in Notice 10 will be 
utilized. Therefore, NHTSA is adopting paragraphs S6.2.2 and S6.2.3 of 
Standard No. 105 and paragraph S6.3.11 of Standard No. 135 to read in 
pertinent part as follows: ``* * * an EV's propulsion battery(s) are at 
the maximum state of charge recommended by the manufacturer, as stated 
in the vehicle operator's manual or on a label that is permanently 
attached to the vehicle, or, if the manufacturer has made no 
recommendation, at a state of charge of not less than 95 percent. If 
battery(s) are replaced rather than re-charged, the replacement 
battery(s) are charged and measured for state of charge in accordance 
with these procedures.''
    Chrysler is concerned that proposed paragraph S6.2.3 of Standard 
No. 105 does not allow for charging during the test sequences listed 
and that EVs may not be able to complete the tests without recharging.
    Notice 10 did not propose procedures for re-charging during the 
test sequences because NHTSA did not believe that such re-charging 
would be necessary. However, the agency now realizes that the 
propulsion battery(s) may be depleted such that the vehicle 
automatically shuts-down, reaches a point at which it will not 
accelerate, or the low state of charge lamp is illuminated (Standard 
No. 105, proposed paragraph S5.3.1). If any of these conditions occur, 
during a test sequence, the final rule permits the vehicle to be 
accelerated to brake test speed by auxiliary means since some tests are 
required to be conducted within a time limit that would preclude re-
charging or replacing the battery(s) with one that is fully charged. 
Accordingly, paragraph S6.2.3 of Standard No. 105 and paragraph 
S6.3.11.3 of Standard No. 135, as adopted, clarify this. Each states 
that ``* * * No further charging of the propulsion batteries occurs 
during any of the performance tests in the test sequence of this 
standard. If the propulsion batteries are depleted during a test 
sequence such that the vehicle reaches automatic shut-down, will not 
accelerate, or the low state of charge brake warning lamp is 
illuminated, the vehicle is to be accelerated to brake test speed by 
auxiliary means until the test sequence is completed.''
    By adopting this test condition, NHTSA intends that the batteries 
be essentially at full charge at the beginning of each test sequence.

D. Testing in Gear as Opposed to Testing in Neutral

    This issue involves testing EVs in which RBS is not part of the 
service brake system. For such vehicles, Notice 10 proposed to amend 
Standards Nos. 105 (S6.2.4(b)) and No. 135,(S6.3.13) to state that 
``the RBS is operational and set to produce the maximum regenerative 
braking effect during the burnish tests, and is disabled during the 
test procedures.''
    GM commented that the requirement that a RBS that is not part of 
the service brake system be disabled for all tests other than 
burnishing tests is in conflict with other test procedures. Some of the 
test procedures in both Standards Nos. 105 and 135 require that the 
vehicle be tested with the transmission in gear. If an EV has a RBS 
that is not part of the service brake system and the RBS is designed to 
operate when the transmission is in gear, the RBS would have to be 
disconnected for the in-gear test procedures. GM recommends that the 
standards state that the RBS need not be disabled for in-gear braking 
if the RBS can be disabled only through ``tampering'' when the 
transmission is in gear. GM notes that the number of tests affected is 
relatively small and the

[[Page 46912]]

high state of charge required at the beginning of these tests will 
result in a low level of regenerative braking.
    Chrysler remarked that when internal combustion engine (ICE) 
vehicles are tested in gear, they take advantage of the braking effects 
of the engine and transmission. Chrysler believes that EVs should be 
allowed to use their RBS for in-gear testing since it is analogous to 
the engine and transmission braking effects in ICE vehicles.
    In Nissan's opinion, RBS should be allowed to be operational during 
the in-gear brake testing procedures, whether or not the RBS is part of 
the service brake system.
    Toyota believes that the heating snub test, proposed paragraph 
S7.13 of Standard No. 135, should be conducted in the ``in-gear'' mode, 
to be consistent with the burnishing tests and to conform with ICE 
vehicle testing.
    Finally, Honda commented that, since the proposed test conditions 
in both standards require that the drive line be engaged during the 
braking procedures, the ``in gear'' testing specification should be 
changed to allow the option of testing in neutral for vehicles with RBS 
that is activated when the transmission is in gear.
    NHTSA agrees with GM that a requirement to conduct certain tests in 
gear with the RBS disconnected would conflict with the design of many 
EVs. For these designs, the RBS is activated when the vehicle is in 
gear and deactivated in the neutral transmission position. For EVs in 
which the RBS is not part of the service brake system, meeting the 
proposed test conditions would, as previously written, require 
``tampering'' with the RBS to disengage it while the vehicle is in 
gear. If the RBS is disengaged when the transmission is in the neutral 
position, these tests can be conducted in neutral, as suggested by 
Honda. The agency disagrees with the GM statement that most of the test 
procedures are conducted in neutral. While this is true for Standard 
No. 135, there are a significant number of in-gear test procedures in 
Standard No. 105.
    NHTSA agrees with Chrysler that the RBS functions in much the same 
manner in EVs as does the engine and transmission braking effect in ICE 
vehicles. If the RBS is active, it provides vehicle deceleration forces 
in a manner similar to the engine and transmission for an ICE vehicle. 
However, if the RBS is not part of the service brake system, its use is 
optional in most cases. There is no assurance when the RBS is not part 
of the service brake system that it will be engaged or activated by the 
driver at any given time. This is the primary reason Notice 10 proposed 
that the test procedures be conducted with the RBS non-functional if 
the RBS is not part of the service brake system.
    NHTSA also disagrees with Toyota's recommendation that the heating 
snub test in proposed paragraph S7.13 of Standard No. 135 be conducted 
with the RBS engaged. The same reasoning applies in the case of heating 
snubs, that is, if the RBS is not part of the service brake system, its 
use will be optional in most cases, and there is no assurance when the 
RBS is not part of the service brake system that it will be engaged or 
activated by the driver at any given time.
    NHTSA has decided that the requirements proposed in Notice 10 for 
vehicles in which the RBS is not part of the service brake system need 
to be modified to address in-gear testing. Thus, the final rule 
requires that manufacturers render RBS inoperative, including placing 
the transmission in the neutral position if the RBS is deactivated in 
neutral, during testing under conditions that would otherwise require 
the vehicle to be in gear.
    Accordingly, paragraph S6.2.4(b) of Standard No. 105 and paragraph 
S6.3.13 of Standard No. 135 are adopted to read as follows: ``For an EV 
equipped with an RBS that is not part of the service brake system, the 
RBS is operational and set to produce the maximum regenerative braking 
effect during the burnish tests, and is disabled during the test 
procedures. If the vehicle is equipped with a neutral position that 
automatically disables the RBS, the test procedures which are 
designated to be conducted in gear may be conducted in neutral.''

E. Testing at Low State of Charge

    (i) Low state of charge measurement. With respect to state of 
charge of the propulsion batteries, paragraph S6.2.6 proposed in Notice 
10 in part that: ``A vehicle equipped with electrically-actuated 
service brakes also performs the tests specified in S7.3, S7.5, S7.7 
through S7.11, and S7.13 through S7.19 of this standard with the 
batteries providing power to those electrically-actuated brakes, at the 
beginning of each test, in a depleted state of charge for condition 
(a), (b), or (c) of this paragraph as appropriate.'' Proposed paragraph 
S6.3.12 of Standard No. 135 was similar. Paragraphs S6.2.6(a) and 
S6.2.6(b) of Standard No. 105 would require that propulsion battery(s) 
used to power electrically-actuated service brakes be at a state of 
charge that is not more than two percent and not less than one percent 
above the state of charge that would shut down the propulsion system or 
activate the brake failure warning lamp. Paragraph S6.2.6(c) of 
Standard No. 105 would require that auxiliary battery(s) that are used 
to power electrically-actuated service brakes be at a state of charge 
that is not more than two percent and not less than one percent above 
the state of charge that would activate the brake failure warning lamp.
    Toyota, GM, and Nissan commented on the conditions and procedures 
proposed in Notice 10 for paragraphs S6.2.6 (a) and (b) of Standard No. 
105 in which the propulsion battery(s) are used to power electrically-
actuated service brakes. These commenters recommended that the test 
conditions be modified to reduce the burden of the state of charge 
measurement technique. The commenters argued that, with current 
technology, it would be extremely difficult for many test facilities to 
measure the state of charge with one or two percent accuracy. These 
commenters recommended that the agency adopt a five percent initial 
battery(s) state of charge for testing under S6.2.6 of Standard No. 105 
and S6.3.12 of Standard No. 135.
    Based on these comments, NHTSA believes that the one to two percent 
state of charge range proposed as the initial test condition for the 
propulsion and auxiliary battery(s) used in low state of charge tests 
would be difficult to measure. A five percent state of charge would not 
appreciably change the stringency of the requirements, but would 
substantially reduce the state of charge measurement burden.
    For these reasons, Standard No. 135 (S6.3.12(c)), as adopted, will 
state that ``* * * the auxiliary battery(s) is at not more than five 
percent above the actual state of charge at which the brake failure 
warning signal, required by S5.5.1(e) of this standard, is 
illuminated.'' The propulsion battery(s) referenced in S6.3.12 (a) and 
(b) of Standard No. 135 will also be charged to not more than five 
percent above the state of charge that would cause shut down or 
illumination of the brake failure warning lamp. The auxiliary 
battery(s) in paragraph S6.2.6(c) of Standard No. 105, and the 
propulsion battery(s) in paragraphs S6.2.6 (a), and (b), will be 
charged to not more than five percent above the state of charge that 
would illuminate the brake system indicator lamp as required in 
S5.3.1(e), or the state of charge that would result in automatic shut-
down of the propulsion system.
    (ii) Low State of charge testing. The agency proposed in Notice 10 
that EVs with electrically actuated service brakes be required to 
complete a series of brake performance tests with the battery(s) at

[[Page 46913]]

a low state of charge. With respect to the state of charge of 
propulsion batteries, paragraph S6.2.6 of Standard No. 105 proposed in 
part that: ``A vehicle equipped with electrically-actuated service 
brakes also performs the tests specified in S7.3, S7.5, S7.7, through 
S7.11, and S7.13 through S7.19 of this standard with the battery(s) 
providing power to those electrically-actuated brakes, at the beginning 
of each test, in a depleted state of charge for condition (a), (b), or 
(c) of this paragraph as appropriate.'' To the same effect was proposed 
paragraph S6.3.12 of Standard No. 135.
    The agency argued that a vehicle that can be operated should be 
able to perform a full series of brake tests. The agency further stated 
that the purpose of the test series is to assure that a vehicle will 
operate properly if any one of the test conditions occur during 
operation.
    GM, in its comments to Notice 10, continued to express the concern 
it expressed in response to Notice 7. That is, the requirement for a 
full series of tests under depleted battery(s) conditions is 
unreasonable and unnecessary. All commenters responding to Notice 7 
indicated that it was unreasonable and unnecessary to subject an EV to 
a complete brake test series with depleted battery(s). They indicated 
that a vehicle with a low state of charge in the propulsion battery(s) 
could be expected to perform a low number of accelerations prior to 
becoming immobile. The commenters argued that it was unreasonable to 
require braking capacity that far exceeds propulsion capacity.
    After further consideration, the agency agrees that a full series 
of tests is not necessary because it is very unlikely that a vehicle 
with a low state of charge would require the braking capacity needed to 
perform an entire brake test series under either Standard No. 105 or 
Standard No. 135. NHTSA also believes that current propulsion 
battery(s) would need substantial redesign to comply with the proposed 
requirements.
    GM requested that the agency reconsider the procedure for a 
dedicated low charge braking test that the company had recommended in 
its comments to Notice 7.
    The agency feels that an abbreviated braking test procedure similar 
to the one recommended by GM in its comments to Notice 7 is 
appropriate, and that it is sufficient for an EV with electrically-
actuated service brakes to demonstrate braking power while it can still 
be accelerated.
    GM also indicated that the recharging procedures for these tests 
needed clarification. The proposed test procedure for low battery(s) 
state of charge testing specified in Notice 10 does not allow for 
recharging, but states that a vehicle may be accelerated to test speed 
by auxiliary means. The test procedures adopted in the final rule do 
not allow for recharging of the battery(s) that provide power for 
electrically-actuated service brakes. An auxiliary means is to be 
provided as necessary to accelerate the vehicle to test speed, as 
proposed in Notice 10.
    The agency is specifying that an abbreviated low state of charge 
braking performance test series be conducted on EVs utilizing 
electrically-actuated service brakes. In addition, S6.2.6 of Standard 
No. 105 and S6.3.12 of Standard No. 135 are adopted to read: ``A 
vehicle equipped with electrically-actuated service brakes also 
performs the following test series. Conduct 10 stopping tests from a 
speed of 100 kph or the maximum vehicle speed, whichever is less. At 
least two of the 10 stopping distances must be less than or equal to 70 
meters. The vehicle is to be loaded to GVWR for these tests and the 
transmission shall be in the neutral position when the service brake 
control is actuated and throughout the remainder of the test. The 
battery(s) providing power to those electrically-actuated service 
brakes, at the beginning of each test, shall be in a depleted state of 
charge for conditions (a), (b), or (c) of this paragraph as 
appropriate. An auxiliary means may be used to accelerate an EV to test 
speed.''
    Nissan believed that it is not technically feasible to detect state 
of charge of an auxiliary battery and recommends that the agency delete 
the low state of charge performance tests for vehicles with auxiliary 
batteries that provide power for vacuum boosters and hydraulic pumps 
(electrically-actuated brakes).
    Nissan believes that actual fluid pressure or vacuum should be 
monitored instead of the state of charge of an auxiliary battery in 
vehicles which have electrically-actuated service brakes. Notice 10 did 
not propose that auxiliary battery(s) that are used to power hydraulic 
pumps or vacuum motors be monitored for state of charge. The proposed 
requirement applies to auxiliary battery(s) that power electrically-
actuated service brakes, brakes in which the brake control signal is 
electrically transmitted from the brake control unit to the foundation 
brakes, and RBS that is part of the service brake system. Auxiliary 
battery(s) that power hydraulic pumps and vacuum motors are not 
included under the proposed requirement for state of charge monitoring. 
No action is taken in response to this comment.

7. Issues Related to Test Conditions

A. Initial Brake Temperature (IBT)

    HQ believes that its braking system will not achieve the IBT 
required in section S7 Road test procedures and performance 
requirements of Standard No. 135 for the foundation or friction brakes 
when the heating tests are conducted because a large percentage of the 
braking forces are supplied by dynamic (dissipative) braking. HQ 
suggests that the IBT condition be made optional for EVs as well as the 
test sequence S7.13-S7.16 because the HQ dynamic braking system will 
develop low temperatures in the friction brake system components.
    NHTSA agrees that the dynamic braking forces (RBS-type) of the HQ 
braking system could result in low brake temperatures for the 
foundation friction brakes. Neither Standard No. 105 nor Standard No. 
135 specify procedures for establishing the IBT for those test 
procedures that require an initial brake temperature. The agency 
believes that the IBT condition can be met if several stops are 
performed with the RBS disabled or disengaged, and that disabling or 
disengaging the RBS system would not be impracticable. The agency also 
believes that the hot performance and recovery performance tests in 
paragraphs S7.13 through S7.16 of Standard No. 135 are an extremely 
important phase of the overall brake testing and that all vehicles with 
friction brakes should perform these tests. Thus, it has made no 
modifications in adopting the IBT condition as proposed.

B. Static Parking Brake Test

    Proposed S7.7.1.3 in Standard No. 105 and S7.12.2(o) in Standard 
No. 135 would add language to clarify the means for activating electric 
parking brakes, to state ``[f]or vehicles with electrically activated 
parking brakes, apply the parking brakes by activating the parking 
brake control.'' NHTSA has adopted the proposed change.

C. Stops With Engine Off (Standard No. 135)

    HQ believes that the vehicle engine off condition for brake testing 
(S7.7.2(a)) represents engine stalling for internal combustion engine 
vehicles and has no direct equivalent for EVs. However, the 
specification that the test is conducted with ``no electromotive 
force'' applied to the motor(s) proposed in paragraph S7.7.3(h) of 
Standard No. 135 is intended to serve the same purpose for

[[Page 46914]]

EVs as testing ICE vehicles with the engine off.
    Nevertheless, HQ believes that the term needs further explanation 
since it is not clear whether regenerative braking using the electric 
motor(s) is allowed under S7.7.3(h). The proposed conditions of 
S7.7.3(h) for EVs during tests that are analogous to ICE vehicle tests 
with the engine off specify that the electric propulsion motor(s) not 
be supplied with any electromotive force, or be switched-off. The RBS 
is not allowed to operate under these test conditions. No amendment of 
the proposal is required, and S7.7.3(h) is adopted as proposed.

8. International Harmonization

    The European Community has not finalized braking standards for EVs 
to date, and the conditions and procedures for EV testing specified in 
this final rule may be adopted by the Europeans.
    NHTSA has been recently provided a current copy of draft Regulation 
13-H (R13-H), the European version of the harmonized brake standard for 
light passenger vehicles. The draft was reviewed with respect to EV 
braking conditions and requirements to determine if they are compatible 
with the EV brake test conditions and requirements in this final rule. 
In general, EV brake system design and performance requirements in 
Standard No. 135 and R13-H are similar. For example, both rules account 
for RBS and both rules distinguish RBS that is part of the service 
brake system from RBS that is not. At this time, NHTSA does not 
anticipate that harmonization of the brake standards will be more 
difficult for EVs than for conventional vehicles.
    In general, R13-H has specified more EV test procedures and 
conditions than the agency has specified in Standard No. 135 as amended 
by this final rule since the Europeans have more EV experience at this 
time. The R-13H draft does not, however, address EV recharging during 
testing or electrically-actuated service brakes for passenger cars. As 
NHTSA's experience increases, it may propose adding specific EV test 
procedures and conditions to the adhesion utilization requirements and 
other areas of performance.
    Whatever future actions NHTSA takes in this area, it will discuss 
requirements for EV brake systems with braking experts from other 
nations. It should be possible for all regulatory authorities to reach 
a consistent harmonized approach when dealing with an emerging 
technology like EV brake systems.
    The reader will find that provisions of this final rule not 
discussed by this notice are substantially the same as those proposed 
by Notice 10.

Effective Dates (Lead Time)

    Notice 10 proposed that EV amendments to Standards Nos. 105 and 135 
become effective 30 days after publication of the final rule.
    Chrysler and Ford stated that one year after publication of the 
final rule would be preferable; if the standard is further amended, 
more lead time may be required for compliance to make necessary design 
modifications. However, an early effective date was supported by GM 
which wishes to certify its EV-1 passenger car to electric vehicle 
braking requirements at the earliest possible date.
    NHTSA believes that the final rule is written in such a manner as 
to accommodate most present EV brake system designs without extensive 
modifications. But it is sensitive to the comments by Ford and Chrysler 
that each may need up to one year for leadtime, should they deem it 
necessary to modify their current EV braking system designs to meet the 
standards promulgated by this document.
    To accommodate all commenters on this issue, NHTSA is adopting an 
early effective date for the electric brake amendments with mandatory 
compliance after one year. The amendments to Standard No. 105, which do 
not change the present requirements relating to hydraulic brake 
systems, will become effective 45 days after their publication. 
However, manufacturers of passenger cars, multipurpose passenger 
vehicles, trucks, and buses, with electric brake systems, need not 
comply until September 1, 1998. Manufacturers of passenger cars with 
hydraulic brake systems already have the option of meeting Standard No. 
105 until September 1, 2000, and this same option is being afforded 
passenger cars with electric brake systems, under companion amendments 
to both Standards Nos. 105 and 135. To accomplish this, Section S3 
Application of Standard No. 105 is being amended to read as follows:

``S3 Application

    (a) This standard applies to the following vehicles with hydraulic 
or electric brake systems: multipurpose passenger vehicles, trucks, and 
buses, and to passenger cars manufactured before September 1, 2000.
    (b) This standard, at the option of a manufacturer of a passenger 
car, multipurpose passenger vehicle, truck, or bus, with an electric 
brake system, does not apply before September 1, 1998.
    (c) At the option of the manufacturer, passenger cars with 
hydraulic or electric brake systems manufactured before September 1, 
2000, may comply with the requirements of Federal Motor Vehicle Safety 
Standard No. 135, Passenger Car Brake Systems, instead of the 
requirements of this standard.''
    Compliance with Standard No. 135 is not mandatory until September 
1, 2000, although manufacturers of passenger cars with hydraulic brake 
systems have the present option of complying with it as an alternative 
to Standard No. 105. The amendments made by this document do not affect 
the hydraulic brake requirements, but add requirements applicable to 
electric vehicle brakes and are incorporated into it effective 45 days 
after publication. The application section of Standard No. 135 is being 
amended to read:

    ``S3 Application. This standard applies to passenger cars 
manufactured on or after September 1, 2000. In addition, passenger 
cars manufactured before September 1, 2000 may, at the option of the 
manufacturer, meet the requirements of this standard instead of 
Federal Motor Vehicle Safety Standard No. 105 Hydraulic and Electric 
Brake Systems.''

    In summary, passenger cars, multipurpose passenger vehicles, 
trucks, and buses, with electric brake systems need not comply with 
Standard No. 105 until September 1, 1998, and may comply before then. 
But all these vehicles must comply with Standard No. 105 on and after 
September 1, 1998. Alternatively, passenger cars with electric brake 
systems may comply with Standard No. 135 at any time before September 
1, 2000, but otherwise must meet Standard No. 105 as of September 1, 
1998, and Standard No. 135 as of September 1, 2000.
    Because of the wish of some manufacturers to offer and certify 
complying vehicles with electric brake systems at an early date, and 
because the amendments do not affect existing requirements for vehicles 
with hydraulic brake systems, it is hereby found that an effective date 
earlier than 180 days after issuance of the amendments is in the public 
interest. Accordingly, the amendments are effective October 20, 1997.

Regulatory Analysis

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

    This rulemaking has not been reviewed under Executive Order 12866. 
NHTSA has considered the economic implications of this regulation and 
determined that it is not significant within the meaning of the DOT

[[Page 46915]]

Regulatory Policies and Procedure. It does not initiate a substantial 
regulatory program or involve a change in policy.

Regulatory Flexibility Act

    The agency has also considered the effects of this rulemaking 
action in relation to the Regulatory Flexibility Act. I certify that 
this rulemaking action will not have a significant economic effect upon 
a substantial number of small entities. Motor vehicle manufacturers are 
generally not small businesses within the meaning of the Regulatory 
Flexibility Act. Accordingly, no Regulatory Flexibility Analysis has 
been prepared.

Executive Order 12612 (Federalism)

    This action has been analyzed in accordance with the principles and 
criteria contained in Executive Order 12612 on ``Federalism.'' It has 
been determined that the rulemaking action does not have sufficient 
federalism implications to warrant the preparation of a Federalism 
Assessment.

National Environmental Policy Act

    NHTSA has analyzed this rulemaking action for purposes of the 
National Environmental Policy Act. The rulemaking action will not have 
a significant effect upon the environment. There is no environmental 
impact associated with adaptation of test procedures to make them more 
appropriate for vehicles already required to comply with the Federal 
motor vehicle safety standards. The rulemaking action would not have a 
direct effect. However, to the extent that this rulemaking might 
facilitate the introduction of EVs which are powered by an electric 
motor drawing current from rechargeable storage batteries, fuel cells, 
or other portable sources of electric current, and which may include a 
nonelectrical source of power designed to charge batteries and 
components thereof, the rulemaking would have a beneficial effect upon 
the environment and reduce fuel consumption because EVs emit no 
hydrocarbon emissions and do not depend directly upon fossil fuels to 
propel them.

Executive Order 12778 (Civil Justice Reform)

    This rule will 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. Section 30161 of Title 49 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.

List of Subjects in 49 CFR Part 571

    Imports, Motor vehicle safety, Motor vehicles

PART 571--FEDERAL MOTOR VEHICLE SAFETY STANDARDS

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


Sec. 571.105  [Amended]

    2. Section 571.105 is amended by:
    a. Revising its heading;
    b. Revising S1, S3, the definitions of ``backup system'' and 
``split service brake system'' in S4 and adding to S4, in alphabetical 
order, definitions of ``Electric vehicle or EV'', ``Electrically-
actuated service brakes'', and ``Regenerative braking system or RBS'';
    c. Amending S5.1.1.4 to add a sentence at the end thereof below the 
undesignated table;
    d. Adding S5.1.2.3, S5.1.2.4, and S5.1.3.5;
    e . Revising the introductory text of S5.3.1 and adding S5.3.1 (e), 
(f), and (g);
    f. Revising the introductory text of S5.3.5(c)(1) and S5.4.3;
    g. Withdrawing the revision of S5.5 and additions of S5.5.1 and 
S5.5.2 published at 60 FR 13256, Mar. 10, 1995, and the revision of 
S5.5.1 published at 60 FR 63979, Dec. 13, 1995 that were to become 
effective March 1, 1999, and revising S5.5 as currently in effect and 
adding S5.5.1 and S5.5.2;
    h. Adding S6.2 through S6.2.6;
    i. Revising the introductory text of S7.7.1.3 and adding 
S7.7.1.3(c);
    j. Adding S7.9.5 and S7.9.6; and
    k. Adding S7.10.3
    The revised and added heading and paragraphs read as follows:


Sec. 571.105  Standard No. 105; Hydraulic and electric brake systems.

    S1. Scope. This standard specifies requirements for hydraulic and 
electric service brake systems, and associated parking brake systems.
* * * * *
    S3. Application.
    (a) This standard applies to the following vehicles with hydraulic 
or electric brake systems: multipurpose passenger vehicles, trucks, and 
buses, and to passenger cars manufactured before September 1, 2000.
    (b) This standard, at the option of a manufacturer of a passenger 
car, multipurpose passenger vehicle, truck, or bus, with an electric 
brake system, does not apply before September 1, 1998.
    (c) At the option of the manufacturer, passenger cars with 
hydraulic or electric brake systems manufactured before September 1, 
2000, may comply with the requirements of Federal Motor Vehicle Safety 
Standard No. 135, Passenger Car Brake Systems, instead of the 
requirements of this standard.
    S4. Definitions.
* * * * *
    Backup system means a portion of a service brake system, such as a 
pump, that automatically supplies energy, in the event of a primary 
brake power source failure.
* * * * *
    Electric vehicle or EV means a motor vehicle that is powered by an 
electric motor drawing current from rechargeable storage batteries, 
fuel cells, or other portable sources of electrical current, and which 
may include a non-electrical source of power designed to charge 
batteries and components thereof.
    Electrically-actuated service brakes means service brakes that 
utilize electrical energy to actuate the foundation brakes.
* * * * *
    Regenerative braking system or RBS means an electrical energy 
system that is installed in an EV for recovering or dissipating kinetic 
energy, and which uses the propulsion motor(s) as a retarder for 
partial braking of the EV while returning electrical energy to the 
propulsion batteries or dissipating electrical energy.
* * * * *
    Split service brake system means a brake system consisting of two 
or more subsystems actuated by a single control, designed so that a 
single failure in any subsystem (such as a leakage-type failure of a 
pressure component of a hydraulic subsystem except structural failure 
of a housing that is common to two or more subsystems, or an electrical 
failure in an electric subsystem) does not impair the operation of any 
other subsystem.
* * * * *
    S5.1.1.4 * * * For an EV, the speed attainable in 2 miles is 
determined with the propulsion batteries at a state of charge of not 
less than 95 percent at the beginning of the run.
    S5.1.2 Partial failure.
* * * * *

[[Page 46916]]

    S5.1.2.3 For a vehicle manufactured with a service brake system in 
which the brake signal is transmitted electrically between the brake 
pedal and some or all of the foundation brakes, regardless of the means 
of actuation of the foundation brakes, the vehicle shall be capable of 
stopping from 60 mph within the corresponding distance specified in 
Column IV of Table II with any single failure in any circuit that 
electrically transmits the brake signal, and with all other systems 
intact.
    S5.1.2.4 For an EV manufactured with a service brake system that 
incorporates RBS, the vehicle shall be capable of stopping from 60 mph 
within the corresponding distance specified in Column IV of Table II 
with any single failure in the RBS, and with all other systems intact.
* * * * *
    S5.1.3.5 Electric brakes. Each vehicle with electrically-actuated 
service brakes (brake power unit) shall comply with the requirements of 
S5.1.3.1 with any single electrical failure in the electrically-
actuated service brakes and all other systems intact.
* * * * *
    S5.3 Brake system indicator lamp. * * *
    S5.3.1 An indicator lamp shall be activated when the ignition 
(start) switch is in the ``on'' (``run'') position and whenever any of 
the conditions (a) or (b), (c), (d), (e), (f), and (g) occur:
* * * * *
    (e) For a vehicle with electrically-actuated service brakes, 
failure of the source of electric power to the brakes, or diminution of 
state of charge of the batteries to less than a level specified by the 
manufacturer for the purpose of warning a driver of degraded brake 
performance.
    (f) For a vehicle with electric transmission of the service brake 
control signal, failure of a brake control circuit.
    (g) For an EV with RBS that is part of the service brake system, 
failure of the RBS. An amber lamp may be used displaying the symbol 
``RBS.'' RBS failure in a system that is part of the service brake 
system may also be indicated by an amber lamp that also indicates ABS 
failure and displays the symbol ``ABS/RBS''.
* * * * *
    S5.3.5 * * *
    (c)(1) If separate indicators are used for one or more of the 
conditions described in S5.3.1(a) through S5.3.1(g) of this standard, 
the indicator display shall include the word ``Brake'' and appropriate 
additional labeling, except as provided in (c)(1) (A) through (D) of 
this paragraph.
* * * * *
    S5.4.3 Reservoir labeling--Each vehicle equipped with hydraulic 
brakes shall have a brake fluid warning statement that reads as 
follows, in letters at least one-eighth 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--
* * *
    S5.5 Antilock and variable proportioning brake systems.
    S5.5.1 On and after March 1, 1999, each vehicle with a GVWR greater 
than 10,000 pounds, except for any vehicle that has a speed attainable 
in 2 miles of not more than 33 mph, shall be equipped with an antilock 
brake system that directly controls the wheels of at least one front 
axle and the wheels of at least one rear axle of the vehicle. On and 
after March 1, 1999, on each vehicle with a GVWR greater than 10,000 
pounds but not greater than 12,000 pounds, the antilock brake system 
may also directly control the wheels of the drive axle by means of a 
single sensor in the drive line. Wheels on other axles of the vehicle 
may be indirectly controlled by the antilock brake system.
    S5.5.2 In the event of any failure (structural or functional) in an 
antilock or variable proportioning brake system, the vehicle shall be 
capable of meeting the stopping distance requirements specified in 
S5.1.2 for service brake system partial failure. For an EV that is 
equipped with both ABS and RBS that is part of the service brake 
system, the ABS must control the RBS.
* * * * *
    S6.2 Electric vehicles and electric brakes.
    S6.2.1 The state of charge of the propulsion batteries is 
determined in accordance with SAE Recommended Practice J227a, Electric 
Vehicle Test Procedure, February 1976. The applicable sections of J227a 
are 3.2.1 through 3.2.4, 3.3.1 through 3.3.2.2, 3.4.1 and 3.4.2, 4.2.1, 
5.2, 5.2.1, and 5.3.
    S6.2.2 At the beginning of the first effectiveness test specified 
in S7.3, and at the beginning of each burnishing procedure, each EV's 
propulsion battery is at the maximum state of charge recommended by the 
manufacturer, as stated in the vehicle operator's manual or on a label 
that is permanently attached to the vehicle, or, if the manufacturer 
has made no recommendation, at a state of charge of not less than 95 
percent. If a battery is replaced rather than recharged, the 
replacement battery is to be charged and measured for state of charge 
in accordance with these procedures. During each burnish procedure, 
each propulsion battery is restored to the recommended state of charge 
or a state of charge of not less than 95 percent after each increment 
of 40 burnish stops until each burnish procedure is complete. The 
batteries may be charged at a more frequent interval if, during a 
particular 40-stop increment, the EV is incapable of achieving the 
initial burnish test speed. During each burnish procedure, the 
propulsion batteries may be charged by an external means or replaced by 
batteries that are charged to the state of charge recommended by the 
manufacturer or a state of charge of not less than 95 percent. For EVs 
having a manual control for setting the level of regenerative braking, 
the manual control, at the beginning of each burnish procedure, is set 
to provide maximum regenerative braking throughout the burnish.
    S6.2.3 At the beginning of each performance test in the test 
sequence (S7,3, S7.5, S7.7 through S7.11, and S7.13 through S7.19 of 
this standard), unless otherwise specified, each propulsion battery of 
an EV is at the maximum state of charge recommended by the 
manufacturer, as stated in the vehicle operator's manual or on a label 
that is permanently attached to the vehicle, or, if the manufacturer 
has made no recommendation, at a state of charge of not less than 95 
percent. If batteries are replaced rather than recharged, each 
replacement battery shall be charged and measured for state of charge 
in accordance with these procedures. No further charging of any 
propulsion battery occurs during any of the performance tests in the 
test sequence of this standard. If the propulsion batteries are 
depleted during a test sequence such that the vehicle reaches automatic 
shut-down, will not accelerate, or the low state of charge warning lamp 
is illuminated, the vehicle is to be accelerated to brake test speed by 
auxiliary means.
    S6.2.4 (a) For an EV equipped with RBS, the RBS is considered to be 
part of the service brake system if it is automatically controlled by 
an application of the service brake control, if there is no means 
provided for the driver to disconnect or otherwise deactivate it, and 
if it is activated in all transmission positions, including neutral. 
The RBS is operational during all burnishes and all tests, except for 
the test of a failed RBS.
    (b) For an EV equipped with an RBS that is not part of the service 
brake system, the RBS is operational and set

[[Page 46917]]

to produce the maximum regenerative braking effect during the 
burnishes, and is disabled during the test procedures. If the vehicle 
is equipped with a neutral gear that automatically disables the RBS, 
the test procedures which are designated to be conducted in gear may be 
conducted in neutral.
    S6.2.5  For tests conducted ``in neutral,'' the operator of an EV 
with no ``neutral'' position (or other means such as a clutch for 
disconnecting the drive train from the propulsion motor(s)) does not 
apply any electromotive force to the propulsion motor(s). Any 
electromotive force that is applied to the propulsion motor(s) 
automatically remains in effect unless otherwise specified by the test 
procedure.
    S6.2.6  A vehicle equipped with electrically-actuated service 
brakes also performs the following test series. Conduct 10 stopping 
tests from a speed of 100 kph or the maximum vehicle speed, whichever 
is less. At least two of the 10 stopping distances must be less than or 
equal to 70 meters. The vehicle is loaded to GVWR for these tests and 
the transmission is in the neutral position when the service brake 
control is actuated and throughout the remainder of the test. The 
battery or batteries providing power to those electrically-actuated 
brakes, at the beginning of each test, shall be in a depleted state of 
charge for conditions (a), (b), or (c) of this paragraph as 
appropriate. An auxiliary means may be used to accelerate an EV to test 
speed.
    (a) For an EV equipped with electrically-actuated service brakes 
deriving power from the propulsion batteries, and with automatic shut-
down capability of the propulsion motor(s), the propulsion batteries 
are at not more than five percent above the EV actual automatic shut-
down critical value. The critical value is determined by measuring the 
state-of-charge of each propulsion battery at the instant that 
automatic shut-down occurs and averaging the states-of-charge recorded.
    (b) For an EV equipped with electrically-actuated service brakes 
deriving power from the propulsion batteries, and with no automatic 
shut-down capability of the propulsion motor(s), the propulsion 
batteries are at an average of not more than five percent above the 
actual state of charge at which the brake failure warning signal, 
required by S5.3.1(e) of this standard, is illuminated.
    (c) For a vehicle which has an auxiliary battery (or batteries) 
that provides electrical energy to operate the electrically-actuated 
service brakes, the auxiliary battery(batteries) is (are) at (at an 
average of) not more than five percent above the actual state of charge 
at which the brake failure warning signal, required by S5.3.1(e) of 
this standard, is illuminated.
* * * * *
    S7.7.1 Test procedure for requirements of S5.2.1.
* * * * *
    S7.7.1.3  With the vehicle held stationary by means of the service 
brake control, apply the parking brake by a single application of the 
force specified in (a), (b), or (c) of this paragraph, 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:
* * * * *
    (c) For a vehicle using an electrically-activated parking brake, 
apply the parking brake by activating the parking brake control.
* * * * *
    S7.9 Service brake system test--partial failure.
* * * * *
    S7.9.5  For a vehicle in which the brake signal is transmitted 
electrically between the brake pedal and some or all of the foundation 
brakes, regardless of the means of actuation of the foundation brakes, 
the tests in S7.9.1 through S7.9.3 of this standard are conducted by 
inducing any single failure in any circuit that electrically transmits 
the brake signal, and all other systems intact. Determine whether the 
brake system indicator lamp is activated when the failure is induced.
    S7.9.6  For an EV with RBS that is part of the service brake 
system, the tests specified in S7.9.1 through S7.9.3 are conducted with 
the RBS disconnected and all other systems intact. Determine whether 
the brake system indicator lamp is activated when the RBS is 
disconnected.
* * * * *
    S7.10  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.)
* * * * *
    S7.10.3 Electric brakes.
    (a) For vehicles with electrically-actuated service brakes, the 
tests in S7.10.1 or S7.10.2 are conducted with any single electrical 
failure in the electric brake system instead of the brake power or 
brake power assist systems, and all other systems intact.
    (b) For EVs with RBS that is part of the service brake system, the 
tests in S7.10.1 or S7.10.2 are conducted with the RBS discontinued and 
all other systems intact.
    3. Section 571.135 is amended by:
    a. Revising S3;
    b. Revising the definitions of ``maximum speed'', and ``split 
service brake system'' in S4, and adding in S4, in alphabetical order, 
definitions for ``Electric vehicle'', ``Electrically-actuated service 
brakes'', and ``Regenerative braking system'';
    c. Adding S5.1.3;
    d. Revising the introductory text of S5.4.3 and S5.5.1 and adding 
S5.5.1 (e),(f), and (g);
    e. Revising the introductory text of S5.5.5(d);
    f. Adding S6.3.11.1, S6.3.11.2, S6.3.11.3, S6.3.12, and S6.3.13;
    g. Adding S7.2.4(f), S7.4.5.1, and S7.7.3(h)
    h. Revising S7.10, S7.10.3(f), and S7.10.4;
    i. Adding S7.11.3 (m) and (n); and
    j. Revising S7.12.2(i).
    The revised and added paragraphs read as follows:


Sec. 571.135  Standard No. 135; Passenger Car Brake Systems.

* * * * *
    S3 Application. This standard applies to passenger cars 
manufactured on or after September 1, 2000. In addition, passenger cars 
manufactured before September 1, 2000 may, at the option of the 
manufacturer, meet the requirements of this standard instead of Federal 
Motor Vehicle Safety Standard No. 105 Hydraulic and Electric Brake 
Systems.
    S4. Definitions.
* * * * *
    Electric vehicle or EV means a motor vehicle that is powered by an 
electric motor drawing current from rechargeable storage batteries, 
fuel cells, or other portable sources of electrical current, and which 
may include a non-electrical source of power designed to charge 
batteries and components thereof.
    Electrically-actuated service brakes means service brakes that 
utilize electrical energy to actuate the foundation brakes.
* * * * *
    Maximum speed of a vehicle or VMax means the highest speed 
attainable by accelerating at a maximum rate from a standing start for 
a distance of 3.2 km (2 miles) on a level surface, with the vehicle at 
its lightly loaded vehicle weight, and, if an EV, with the propulsion 
batteries at a state of charge of not less than 95 percent at the 
beginning of the run.
* * * * *

[[Page 46918]]

    Regenerative braking system or RBS means an electrical energy 
system that is installed in an EV for recovering or dissipating kinetic 
energy, and which uses the propulsion motor(s) as a retarder for 
partial braking of the EV while returning electrical energy to the 
propulsion battery(s) or dissipating electrical energy.
    Split service brake system means a brake system consisting of two 
or more subsystems actuated by a single control, designed so that a 
single failure in any subsystem (such as a leakage-type failure of a 
pressure component of a hydraulic subsystem except structural failure 
of a housing that is common to two or more subsystems, or an electrical 
failure in an electric subsystem) does not impair the operation of any 
other subsystem.
* * * * *
    S5.1.3 Regenerative braking system. (a) For an EV equipped with 
RBS, the RBS is considered to be part of the service brake system if it 
is automatically activated by an application of the service brake 
control, if there is no means provided for the driver to disconnect or 
otherwise deactivate it, and if it is activated in all transmission 
positions, including neutral.
    (b) For an EV that is equipped with both ABS and RBS that is part 
of the service brake system, the ABS must control the RBS.
* * * * *
    S5.4.3. Reservoir labeling. Each vehicle equipped with hydraulic 
brakes shall have a brake fluid warning statement that reads as 
follows, in letters at least 3.2 mm (\1/8\ 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:
* * * * *
    S5.5.1. Activation. An indicator shall be activated when the 
ignition (start) switch is in the ``on'' (``run'') position and 
whenever any of conditions (a) through (g) occur:
* * * * *
    (e) For a vehicle with electrically-actuated service brakes, 
failure of the source of electric power to those brakes, or diminution 
of state of charge of the batteries to less than a level specified by 
the manufacturer for the purpose of warning a driver of degraded brake 
performance.
    (f) For a vehicle with electric transmission of the service brake 
control signal, failure of a brake control circuit.
    (g) For an EV with a regenerative braking system that is part of 
the service brake system, failure of the RBS. An amber lamp may be used 
displaying the symbol ``RBS.'' RBS failure in a system that is part of 
the service brake system may also be indicated by an amber lamp that 
also indicates ABS failure and displays the symbol ``ABS/RBS''.
* * * * *
    S5.5.5. Labeling.
* * * * *
    (d) If separate indicators are used for one or more of the 
conditions described in S5.5.1(a) through S5.5.1(g), the indicators 
shall display the following wording:
* * * * *
    S6.3.11 State of charge of batteries for EVs.
    S6.3.11.1 The state of charge of the propulsion batteries is 
determined in accordance with SAE Recommended Practice J227a, Electric 
Vehicle Test Procedure, February 1976. The applicable sections of J227a 
are 3.2.1 through 3.2.4, 3.3.1 through 3.3.2.2, 3.4.1 and 3.4.2, 4.2.1, 
5.2, 5.2.1 and 5.3.
    S6.3.11.2  At the beginning of the burnish procedure (S7.1 of this 
standard) in the test sequence, each propulsion battery is at the 
maximum state of charge recommended by the manufacturer, as stated in 
the vehicle operator's manual or on a label that is permanently 
attached to the vehicle, of, if the manufacturer has made no 
recommendation, not less than 95 percent. During the 200-stop burnish 
procedure, the propulsion batteries are restored to the maximum state 
of charge determined as above, after each increment of 40 burnish stops 
until the burnish procedure is complete. The batteries may be charged 
at a more frequent interval during a particular 40-stop increment only 
if the EV is incapable of achieving the initial burnish test speed 
during that increment. During the burnish procedure, the propulsion 
batteries may be charged by external means or replaced by batteries 
that are at a state of charge of not less than 95 percent. For an EV 
having a manual control for setting the level of regenerative braking, 
the manual control, at the beginning of the burnish procedure, is set 
to provide maximum regenerative braking throughout the burnish.
    S6.3.11.3  At the beginning of each performance test in the test 
sequence (S7.2 through S7.17 of this standard), unless otherwise 
specified, an EV's propulsion batteries are at the state of charge 
recommended by the manufacturer, as stated in the vehicle operator's 
manual or on a label that is permanently attached to the vehicle, or, 
if the manufacturer has made no recommendation, at a state of charge of 
not less than 95 percent. No further charging of any propulsion battery 
occurs during any of the performance tests in the test sequence of this 
standard. If the propulsion batteries are depleted during a test 
sequence such that the vehicle reaches automatic shut-down, will not 
accelerate, or the low state of charge brake warning lamp is 
illuminated, the vehicle is to be accelerated to brake test speed by 
auxiliary means. If a battery is replaced rather than recharged, the 
replacement battery shall be charged and measured for state of charge 
in accordance with these procedures.
    S6.3.12  State of charge of batteries for electrically-actuated 
service brakes. A vehicle equipped with electrically-actuated service 
brakes also performs the following test series. Conduct 10 stopping 
tests from a speed of 100 kph or the maximum vehicle speed, whichever 
is less. At least two of the 10 stopping distances must be less than or 
equal to 70 meters. The vehicle is loaded to GVWR and the transmission 
is in the neutral position when the service brake control is actuated 
and throughout the remainder of the test. Each battery providing power 
to the electrically-actuated service brakes, shall be in a depleted 
state of charge for conditions (a), (b), or (c) of this paragraph as 
appropriate. An auxiliary means may be used to accelerate an EV to test 
speed.
    (a) For an EV equipped with electrically-actuated service brakes 
deriving power from the propulsion batteries and with automatic shut-
down capability of the propulsion motor(s), the propulsion batteries 
are at not more than five percent above the EV actual automatic shut-
down critical value. The critical value is determined by measuring the 
state-of-charge of each propulsion battery at the instant that 
automatic shut-down occurs.
    (b) For an EV equipped with electrically-actuated service brakes 
deriving power from the propulsion batteries and with no automatic 
shut-down capability of the propulsion motor(s), the propulsion 
batteries are at an average of not more than five percent above the 
actual state of charge at which the brake failure warning signal, 
required by S5.5.1(e) of this standard, is illuminated.
    (c) For a vehicle which has one or more auxiliary batteries that 
provides electrical energy to operate the electrically-actuated service 
brakes, each auxiliary battery is at not more than five percent above 
the actual state of charge at which the brake failure

[[Page 46919]]

warning signal, required by S5.5.1(e) of this standard, is illuminated.
    S6.3.13  Electric vehicles.
    S6.3.13.1  (a) For an EV equipped with an RBS that is part of the 
service brake system, the RBS is operational during the burnish and all 
tests, except for the test of a failed RBS.
    (b) For an EV equipped with an RBS that is not part of the service 
brake system, the RBS is operational and set to produce the maximum 
regenerative braking effect during the burnish, and is disabled during 
the test procedures. If the vehicle is equipped with a neutral gear 
that automatically disables the RBS, the test procedures which are 
designated to be conducted in gear may be conducted in neutral.
    S6.3.13.2  For tests conducted ``in neutral'', the operator of an 
EV with no ``neutral'' position (or other means such as a clutch for 
disconnecting the drive train from the propulsion motor(s)) does not 
apply any electromotive force to the propulsion motor(s). Any 
electromotive force that is applied to the propulsion motor(s) 
automatically remains in effect unless otherwise specified by the test 
procedure.
* * * * *
    S7.2.4  Performance requirements.
* * * * *
    (f) An EV with RBS that is part of the service brake system shall 
meet the performance requirements over the entire normal operating 
range of the RBS.
* * * * *
    S7.4.5  Performance requirements. * * *
    S7.4.5.1  An EV with RBS that is part of the service brake system 
shall meet the performance requirement over the entire normal operating 
range of the RBS.
* * * * *
    S7.7.3.  Test conditions and procedures.
* * * * *
    (h) For an EV, this test is conducted with no electromotive force 
applied to the vehicle propulsion motor(s), but with brake power or 
power assist still operating, unless cutting off the propulsion 
motor(s) also disables those systems.
* * * * *
    S7.10  Partial failure.
* * * * *
    S7.10.3.  Test conditions and procedures.
* * * * *
    (f) Alter the service brake system to produce any single failure. 
For a hydraulic circuit, this may be any single rupture or leakage type 
failure, other than a structural failure of a housing that is common to 
two or more subsystems. For a vehicle in which the brake signal is 
transmitted electrically between the brake pedal and some or all of the 
foundation brakes, regardless of the means of actuation of the 
foundation brakes, this may be any single failure in any circuit that 
electrically transmits the brake signal. For an EV with RBS that is 
part of the service brake system, this may be any single failure in the 
RBS.
* * * * *
    S7.10.4  Performance requirements. For vehicles manufactured with a 
split service brake system, in the event of any failure in a single 
subsystem, as specified in S7.10.3(f) of this standard, 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 failure in any component of the service 
brake system, as specified in S7.10.3(f), and after activation of the 
brake system indicator as specified in S5.5.1 of this standard, 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).
    S7.11.3. Test conditions and procedures.
* * * * *
    (m) For vehicles with electrically-actuated service brakes (brake 
power unit), this test is conducted with any single electrical failure 
in the electrically-actuated service brakes instead of a failure of any 
other brake power or brake power assist unit, and all other systems 
intact.
    (n) For an EV with RBS that is part of the service brake system, 
this test is conducted with the RBS disconnected and all other systems 
intact.
* * * * *
    S7.12.2.  Test conditions and procedures.
* * * * *
    (i) For a vehicle equipped with mechanically-applied parking 
brakes, make a single application of the parking brake control with a 
force not exceeding the limits specified in S7.12.2(b). For a vehicle 
using an electrically-activated parking brake, apply the parking brake 
by activating the parking brake control.
* * * * *
    Issued on: August 26, 1997.
Ricardo Martinez, M.D.
Administrator.
[FR Doc. 97-23318 Filed 9-4-97; 8:45 am]
BILLING CODE 4910-59-P