[Federal Register Volume 60, Number 186 (Tuesday, September 26, 1995)]
[Proposed Rules]
[Pages 49544-49552]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 95-23689]



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DEPARTMENT OF TRANSPORTATION
49 CFR Part 571

[Docket No. 85-6; Notice 10]
RIN 2127-AA13


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

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

ACTION: Further supplemental notice of proposed rulemaking (FSNPRM).

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SUMMARY: This notice proposes amendments to FMVSS Nos. 105 Hydraulic 
Brake Systems and 135, Passenger Car Brake Systems, to accommodate 
electric vehicles. The proposal is based on a supplemental notice of 
proposed rulemaking (SNPRM; Notice 7) published on January 15, 1993, 
and responds to comments submitted to that notice. Amendments of FMVSS 
No. 105 based on this FSNPRM (Notice 10) would apply to electric 
trucks, buses, and multipurpose passenger vehicles. They would also 
apply to electric passenger cars which had not availed themselves of 
the option of conforming to FMVSS No. 135, which will become mandatory 
for all passenger cars manufactured on and after September 1, 2000.

COMMENT DATE: Comments on the FSNPRM are due November 27, 1995.

ADDRESSES: Comments should be addressed to Docket 85-6; Notice 10, and 
submitted to Docket Room, NHTSA, Room 5108, 400 Seventh St. SW., 
Washington, DC 20590.

FOR FURTHER INFORMATION CONTACT: T. Droneburg, Office of Vehicle Safety 
Standards, NHTSA (Phone: 202-366-6617; FAX: 202-366-4329).

SUPPLEMENTARY INFORMATION:

Table of Contents

Background
Definitions
Partial failure
Brake system indicator lamp
Procedure for determining battery state of charge
Procedures for charging batteries during burnish
Procedures for charging batteries during performance tests
The appropriate value for low battery charge
Procedure for testing at full charge and low charge
Other test conditions
Static parking brake test
Inoperative brake power or power assist unit
ABS and dynamic parking brake tests
Adhesion utilization--torque wheel method
Proposed effective date
Regulatory analyses
    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)

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). The 
reader is referred to that notice for information on the rulemaking 
history of electric vehicle braking, and for background discussion of 
the proposed brake system requirements.
    Notice 7 proposed amendments to FMVSS No. 105 Hydraulic Brake 
Systems and revised portions of a proposed FMVSS No. 135 Passenger Car 
Brake Systems. FMVSS No. 135 has now been issued as a final rule 
(Notice 8, 60 FR 6411), effective March 6, 1995. Passenger car 
manufacturers, including those of EVs, have the choice of compliance 
with either braking standard between now and September 1, 2000. At that 
time, FMVSS No. 135 will become the sole brake standard that applies to 
passenger cars. However, FMVSS No. 105 will continue to apply to 
vehicles other than passenger cars. Because EVs are not restricted to 
passenger cars, and include pickup trucks, vans, and buses, amendments 
to FMVSS No. 105 are required to accommodate them.
    Comments on the SNPRM were received from General Motors Corporation 
(GM), Mitsubishi Motors America Inc., American Auto Manufacturers 
Association (AAMA), Marc Pelletier and Associates (Pelletier), PSA 
Peugeot Citroen (Peugeot), SMH Swiss Corp. (SMH), Chrysler Corporation, 
Ford Motor Company, ITT TEVES of Germany (ITT), BMW of North America, 
American Honda, and Toyota.
    The comments supported the rulemaking, although Ford, Chrysler, 
Peugeot, and Pelletier argued that it is premature at this time to 
initiate rulemaking because of rapidly advancing technology and the 
chance that a standard might unduly influence or stifle EV brake system 
development and improvement. NHTSA is aware of these concerns and is 
developing its proposals to set safety performance requirements without 
imposing design restrictions.
    Peugeot and Pelletier were concerned with the role of regenerative 
braking systems (RBS) in service brake performance. Both believe that 
RBS 

[[Page 49545]]
should be allowed to contribute to determination of an EV's braking 
ability under the FMVSS. NHTSA agrees in principle, but the agency 
believes that certain conditions must be satisfied in order for RBS to 
be considered to be part of the service brake system. In particular, 
application of any service braking must be by means of the service 
brake control (brake pedal) and there must be no means of declutching 
or turning the RBS on and off. This subject is discussed in more detail 
later in this notice, under the individual requirements.
    The SNPRM's preamble had stated (p. 4650) that all known EV designs 
are equipped with antilock braking systems (ABS). Chrysler agreed that 
this was true for present designs but that it could not be assumed that 
all future EVs would have ABS. NHTSA does not assume that all future 
EVs will have ABS, and the proposed amendments to both standards 
provide for both possibilities. The subject of mandatory ABS for future 
vehicles of all types is being treated in separate rulemaking actions 
by the agency.
    This FSNPRM reflects refinements of the earlier Notice 7 rather 
than presenting a different approach. These refinements are discussed 
below. Unless otherwise indicated, the changes noted apply to both 
FMVSS No. 105 and FMVSS No. 135.

Definitions

    Under Notice 7, ``Maximum speed of an electric vehicle'' would be 
determined in accordance with SAE Recommended Practice J227a Electric 
Vehicle Test Procedure, February 1976, with the propulsion batteries at 
not less than 90 percent of full charge at the beginning of the test 
run.
    GM and Peugeot asked that NHTSA designate the appropriate sections 
of SAE J227a that apply to maximum speed. Under Acceleration 
Characteristics on a Level Road, sections 7.1 through 7.3 of SAE J227a 
specify that the vehicle is to be accelerated from a standing start at 
its maximum attainable, or permissible, acceleration rate until either 
the vehicle's peak speed is reached or until a safe speed limit is 
attained. This procedure is essentially the same as is currently 
specified in both FMVSS 105 and 135, except that the length of the 
roadway used for determining maximum speed is limited to 2 miles. SAE 
J227a places no limit on the length of the roadway, and gives no 
objective criterion for a determination that the actual maximum speed 
has been reached.
    Upon further consideration of this issue, NHTSA has tentatively 
decided that determination of EV maximum speed would be better 
addressed by modification of the existing procedures than by reference 
to portions of SAE J227a that are of doubtful objectivity. Although 
under this FSNPRM roadway length would remain at 2 miles, the agency 
requests comments on whether EVs are incapable of accelerating to their 
maximum speed within 2 miles, and, if so, what greater distance would 
be more appropriate. Commenters should also address any problems a 
longer distance would create for existing test facilities. A sentence 
specifying the state of battery charge would still have to be added to 
both standards. Notice 7 proposed that the lower limit of the state of 
charge be 90 percent; this notice increases that to 95 percent. This 
will allow somewhat faster acceleration of the EV, and will also be 
consistent with the state of charge proposed for the braking 
performance tests. Accordingly, this notice proposes that a sentence 
specifying the state of charge of the batteries for determination of 
maximum speed be added to paragraph S5.1.1.4 of FMVSS No. 105, and to 
the definition of ``maximum speed'' in FMVSS No. 135.
    In Notice 7's proposed definition of ``Regenerative braking system 
(RBS)'', the propulsion motors may be used as a retarder for partial 
braking of the vehicle in addition to the service brake system, while 
returning electrical energy to the batteries. The phrase ``in addition 
to the service brake system'' has been stricken in the revised proposed 
definition to remove the implication that a regenerative braking 
feature cannot be a part of the service brake system, following 
consideration of comments by ITT and SMH. If the RBS is automatically 
controlled by an application of the service brake control, and if there 
is no means for the driver to declutch or otherwise deactivate it, and 
if the vehicle has no ``neutral'' transmission position, then the 
effect of the RBS is always present when the service brake control is 
applied. In that case, NHTSA believes it reasonable to consider the RBS 
to be part of the service brake system. Since the amount of retardation 
provided by a RBS is dependent on the state of charge of the vehicle's 
batteries, the service brake requirements must be met at any state of 
charge. On the other hand, if the RBS is not controlled by the service 
brake pedal, or if it can be disconnected or turned off when the 
service brake control is applied, it is to be deactivated during tests 
of the service brake system, and is considered an auxiliary braking 
device (not part of the service brake system) for purposes of those 
tests. A system that is automatically applied at a low level when the 
accelerator pedal is released and applied at a higher level when the 
brake pedal is depressed could still be considered part of the service 
brake system, as long as the other criteria stated above are met. This 
view of RBS is consistent with the agency's treatment of other non-
friction braking effects, such as exhaust or driveline retarders or 
engine braking.
    In addition, NHTSA is also proposing revising definitions that 
already exist in the two standards, those of ``Backup system'' and 
``Split service brake system.'' The word ``automatically'' would be 
added in ``Backup system'' in FMVSS No. 105 for consistency so that it 
would be identical to the definition of the term in FMVSS No. 135. 
``Split service brake system'' in both standards would be amended to 
specify that the system is ``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.'' This change recognizes the possibility that vehicles may 
be equipped with non-hydraulic subsystems, such as hydraulic on the 
front and electric on the rear.
    NHTSA has declined to redefine ``backup system'', ``brake control 
unit'' and ``directly controlled wheel'' as suggested by Pelletier, 
which failed to provide reasons for its requests.
    NHTSA also declined BMW's request to define EVs to include hybrid-
powered vehicles with RBS because the definition of EV proposed already 
includes vehicles with ``a non-electrical source of power designed to 
charge batteries''. This term, in NHTSA's view, includes an internal 
combustion engine which may provide propulsion as an alternative to 
electric power.
    Pelletier wanted additional definitions for ``compound service 
brake system'', ``electric braking'', ``friction braking'' and 
``electromagnetic braking'' which had not been proposed. But the 
commenter provided no justification for them, nor any indication where 
they would be used in the FMVSS. Therefore, these definitions are not 
being proposed in this notice.
    Finally, BMW questioned NHTSA's apparently interchangeable use of 
the terms ``electric'' and ``electronic'', and recommended the term 
``electric'' for both. In response to this comment, NHTSA is using 
``electric'' where appropriate, but retaining the use of 

[[Page 49546]]
``electronic'' where use of that term is more appropriate.

Partial Failure

    With respect to the partial failure provisions that were proposed 
to be added to FMVSS No. 105 in a new paragraph S5.1.2.3, GM and AAMA 
commented that they could be interpreted as requiring partial failure 
performance during a simultaneous failure of a hydraulic subsystem 
circuit (as described in S5.1.2.1) and an electric subsystem circuit 
(as described in proposed S5.1.2.3). In order to avoid any 
misinterpretation these commenters recommended that S5.1.2.3 be 
modified to clarify that the 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.'' NHTSA agrees, and S5.1.2.3 is 
reproposed with more definitive wording.
    In addition, new wording is 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, thus the present wording in the Standards is not 
appropriate.

Brake System Indicator Lamp

    Notice 7 proposed requirements in both FMVSS that brake system 
indicator lamps must activate under certain conditions ``for a vehicle 
with electric brake actuation'' and ``for a vehicle with electric 
transmission of the brake control signal.''
    BMW commented that, for a failed electric-control transmission, the 
requirement for a failure indicator should be limited to the service 
brake system, and that indication of failures of an electric control 
transmission of the parking brake should be left to the manufacturer. 
NHTSA agrees. The purpose of the indicator is to evaluate the integrity 
of the electric control transmission circuitry which, if failed, will 
have an effect on the performance of the service brakes. Accordingly, 
NHTSA is adding the word ``service'' to Notice 7's proposed S5.3.1 (e) 
and (f) of FMVSS No. 105 and S5.5.1 (e) and (f) of FMVSS No. 135.
    GM, Ford, AAMA, Peugeot, BMW, and Honda recommended that failure of 
RBS should only be indicated for EVs that depend upon RBS to meet the 
stopping distance requirements. NHTSA disagrees, and believes that any 
failure of a part of the service brake system should be indicated, 
whether or not that component is required for the vehicle to meet the 
stopping distance requirements. If a vehicle is equipped with RBS which 
is part of the service brake system, then the failure warning 
requirement should apply to it. The suggestion of the commenters is 
akin to saying, for example, that if a vehicle is capable of meeting 
the service brake stopping distance requirements with its rear brakes 
disconnected, then there is no need to warn a driver of a failure in 
the vehicle's rear brakes. NHTSA does not see any logic in the 
commenters' views.
    Toyota commented that an RBS failure indicator should be amber 
rather than red because the driver would still be able to bring the 
vehicle safely to a stop with the hydraulic brake system. NHTSA has not 
adopted Toyota's suggestion. The red indicator color signifies that the 
EV's deceleration capability has decreased due to a failure in the 
service brake system, and this is true whether the failure is in a 
hydraulic circuit or in the RBS.

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). For clarification, this is being reproposed to 
specify 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.

Procedures for Charging Batteries During Burnish

    Notice 7 proposed that ``[d]uring the burnish procedure, the 
propulsion batteries may be charged by external means if the vehicle is 
otherwise unable to complete the burnish procedure'' (proposed S6.2.2 
of FMVSS No. 105, S6.3.11.2 of FMVSS No. 135).
    GM and AAMA believe it is important to specify clearly the battery 
state-of-charge for the entire burnish procedure so that different 
testers obtain the same results when evaluating a given vehicle design. 
In their view, the state of battery charge can have a dramatic effect 
on the amount of brake burnish that occurs in EVs, and that it is 
especially important in EVs with regenerative braking. At the extreme, 
it is likely that an EV performing the 200-stop burnish with no 
regenerative braking will experience a significantly greater degree of 
brake burnish than an EV with maximum regenerative braking. GM, 
Chrysler and Ford recommended that the batteries be charged to 95 per 
cent or greater capacity at 40-stop increments.
    NHTSA agrees with these comments. The burnish procedures 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, these sections are being reproposed to specify a 
condition of 95 percent or greater battery charge after each increment 
of 40 burnish stops. In response to comments by Ford and GM, charging 
at a more frequent interval would be permitted during a 40-stop 
interval if the vehicle is incapable of achieving the initial burnish 
test speed during that particular 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. Substitution responds to Honda's concern that the time 
needed for recharging batteries could lead to a protracted test.
    In addition, 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. This proposed condition is being added at the suggestion 
of GM which recommended specifying the setting for an RBS control that 
is driver operated.

Procedure for Charging Batteries During Performance Testing

    This affects proposed S6.2.3 of FMVSS No. 105 and S6.3.11.3 of 
FMVSS No. 135. Under Notice 7, the propulsion batteries would not be 
recharged during the road tests between burnish procedures. GM, AAMA, 
Chrysler, Ford, and Honda, all concerned that EVs might not be capable 
of completing the post-burnish road test sequence on a single battery 
charge, recommended that the provisions be modified to prescribe the 95 
percent or greater state of charge at the onset of each road test 
procedure and to provide explicit instructions for battery recharging 
during the road test sequence.
    NHTSA concurs with the comment that having the state of charge at 
95 percent or greater only at the beginning of the first performance 
test may create problems with EVs obtaining the test speeds for the 
latter tests of the sequence, having the necessary driving range to 
complete the tests, and being able to minimize the fluctuations in the 
RBS. Therefore, the procedure proposed in Notice 7 is modified to 
specify that the batteries be charged to not less than 

[[Page 49547]]
95 percent of capacity at the start of each road test procedure. 
Substitution of batteries charged to not less than 95 percent of 
capacity would be allowed as an alternative to recharging. However, no 
further charging of the propulsion batteries would occur during the 
performance tests themselves.
    Mitsubishi asked that the lower limit of charge of the propulsion 
batteries at the beginning of the first brake test be changed to from 
95 percent to 90 percent, because the high speed test is carried out at 
not less than 90 percent of full charge, and because it believes that 
it is difficult to distinguish a fully charged condition with an 
accuracy of 5 percent. NHTSA does not agree with these comments. Under 
Notice 7, the state of charge at the beginning of each test would be at 
not less than 95 percent of full charge. By adopting this test 
condition, NHTSA intends that the batteries be essentially at full 
charge, and the 5 percent tolerance allows a reasonable margin for 
accuracy of measurement.

The Appropriate Value for Low Battery Charge

    Under Notice 7 (S6.2.6 of FMVSS No. 105, S6.3.11.6 of FMVSS No. 
135), EVs equipped with electric brakes would perform certain specified 
tests ``with the propulsion batteries at one percent or less of full 
charge.'' GM, AAMA, and Chrysler commented that the proposed 1 percent 
state of charge for an EV's propulsion batteries is far more stringent 
than what is required to satisfy the safety need to assure the 
efficiency of an EV's brake system as the propulsion battery charge 
declines to minimum levels. AAMA commented that an EV in actual use 
would never undergo all the different types of stops prescribed in the 
standard after it reaches the threshold of immobility.
    Comments indicated that those EVs with electric brake systems have 
the systems receiving power either from the EV's propulsion batteries, 
or from an auxiliary battery. BMW and Chrysler also indicated that 
automatic shut-down of the propulsion motors is usually provided to 
avoid damaging the batteries at low charge and to provide a continuing 
source of energy for lighting and hazard warning system flashers. 
However, not all EVs have this automatic shut-down feature.
    This FSNPRM takes each of the above into account. For EVs equipped 
with electric brakes powered by the propulsion batteries, at the 
beginning of each of the specified tests, for those EVs with automatic 
shut-down capability of the propulsion system, the propulsion batteries 
would be not less than one percent and not more than two percent above 
the EV actual automatic shut-down critical value. The critical value is 
determined by measuring the state-of-charge of the propulsion 
battery(s) at the instant that automatic shut-down occurs. For those 
EVs with no automatic shut-down capability, the batteries would be at 
not less than one percent and not more than two percent above the state 
of charge at which the brake failure warning indicator is illuminated. 
For vehicles which have an auxiliary battery(s) that provides 
electrical energy to operate the electric brakes (whether EVs or not) 
the auxiliary batteries would be at not less than one percent and not 
more than two percent above the state of charge at which the brake 
failure warning indicator is illuminated.

Procedure for Testing at Full Charge and Low Charge

    GM thought that NHTSA should add a modified effectiveness test near 
the end of the road test sequence, specifically, immediately after the 
spike stop test (S7.17-FMVSS No. 105) or the recovery performance test 
(S7.17-FMVSS No. 135). Such a test with depleted batteries could be 
used to show that brakes operate effectively under a depleted charge 
condition. NHTSA declines to accept this suggestion. The intent of the 
standard is not to match real-world driving conditions, but simply to 
assure that an EV will continue to operate safely if any one of the 
test conditions occurs while the vehicle is in operation.
    GM also recommended that this new test be applicable to all EVs 
rather than limiting it to EVs equipped with electric brakes as 
proposed in the SNPRM. The justification for this suggestion is that 
EVs with conventional hydraulic brakes could rely on electricity for 
certain aspects of brake performance, such as power assist.
    NHTSA has decided not to propose the new test suggested by GM. 
There is already a failed power assist test in the standard, and the 
approach proposed satisfactorily treats the low battery charge 
situation.

Other Test Conditions

    GM informed NHTSA that it has found it can be difficult to achieve 
the minimum initial brake temperatures specified in FMVSS Nos. 105 and 
135 when relatively high levels of regenerative braking are present. GM 
recommended that manufacturers be allowed the option of disregarding 
the prescribed initial brake temperatures when testing EVs equipped 
with RBS. However, GM believed that the temperatures could be achieved 
if the agency adopted its recommendation to specify that batteries be 
charged to 95 percent or greater at the onset of each of the road test 
procedures. Since NHTSA has, in fact, made this change in this FSNPRM, 
the agency does not anticipate that EVs equipped with RBS will have any 
difficulty achieving initial brake temperatures for the road test 
procedures.
    Peugeot was concerned that S6.3.11.5 as proposed for FMVSS No. 135 
in Notice 7 (S6.3.13.2 of this FSNPRM) would not allow use of its 
steering column lock to disable the EV motor for tests to be conducted 
``in neutral.'' The language permits the use of any means with which 
the vehicle is equipped that disconnects the drivetrain from the 
electric propulsion source. However, the agency would interpret that 
language as meaning any means that is available while the vehicle is 
being driven. A steering column key lock would only be used when the 
vehicle is parked, and as such would not be available during driving. 
Therefore, the vehicle would be considered to have no neutral position, 
and would be tested accordingly.
    Comments were also received on the vehicle test condition of 
proposed S7.7.2(e) of FMVSS No. 135. The test is conducted ``with no 
electromotive force applied to the vehicle propulsion motor(s)''. 
Pelletier would qualify this phrase by adding ``other than any 
electromagnetic force that is automatically applied.'' In NHTSA's 
opinion, this addition is unnecessary. The electromagnetic force 
referred to is a residual force resulting from the magnetic fields 
within the motor, and is not considered to be ``applied'' to the motor.

Static Parking Brake Test

    Proposed S7.7.1.3 in FMVSS No. 105 and S7.12.2(o) in FMVSS No. 135 
would add language to clarify the means for activating electric parking 
brakes. GM believed that Notice 7's language would be restricted to 
designs which utilize the foundation brake friction elements to provide 
the parking brake function. It asked the agency to consider modifying 
the requirement to read: ``[f]or vehicles with electrically activated 
parking brakes, apply the parking brakes by activating the parking 
brake control.'' NHTSA concurs with this suggestion and appropriate 
changes are being proposed in this FSNPRM.

Inoperative Brake Power or Power Assist Unit

    Toyota commented that S7.10.3 (FMVSS No. 105) and S7.11.3(m) (FMVSS 
No. 135), as proposed by the SNPRM could be read as requiring 

[[Page 49548]]
vehicles to be tested to simulate simultaneous failure of an 
electrically-actuated brake system and another brake power or power 
assist unit. In response to Toyota's comment, modified language is 
proposed to clarify that tests would be ``conducted with any single 
electrical failure in the electrically-actuated brake system instead of 
a failure of any other brake or brake power assist unit, and all other 
systems intact.''

ABS and Dynamic Parking Brake Tests

    FMVSS No. 135 as issued did not adopt the proposed S7.3 ABS 
performance, of which S7.3.4 Test procedures and performance 
requirements and the SNPRM's proposed S7.3.4.4 would have been a part. 
Therefore S7.3.4.4, or a variation thereof, is not being reproposed at 
this time.
    Nor did FMVSS No. 135 as issued adopt a dynamic parking brake test, 
thus rendering it unnecessary for the agency to adopt proposed 
S7.13.1(d) which would have excepted electric parking brakes from such 
a test.

Adhesion Utilization--Torque Wheel Method

    With respect to the application of the torque wheel test to EVs 
with electric brakes and/or RBS (proposed in Notice 7 as S7.4.5.3 of 
Standard No. 135, now proposed as S7.4.5.1), Notice 7 asked for 
comments, pointing out that the torque wheel method utilizes hydraulic 
line pressure in the calculations which obviously would not be 
available for electric brakes. GM commented that some adaptation of the 
method might be required for an EV that was manufactured with 
electrically actuated front brakes and without ABS. Mitsubishi 
recommended that an alternative method for calculating the torque wheel 
test for EVs with RBS be incorporated, such as a test that calculates 
the amount of braking effort exerted by the operator on the brake 
pedal. Ford believes that the current torque wheel test procedure is 
valid in concept but must be adjusted to be more comprehensive for 
mixed type brake systems.
    NHTSA is aware that the torque wheel test will only accommodate 
vehicles with hydraulic brakes on at least one axle, and that any 
vehicle with ABS is not subject to the test. For vehicles with electric 
brakes on all wheels, the torque wheel test would have to be studied in 
depth to find the correct factors and test procedures for converting 
electrical energy into brake torque for purposes of calculating 
objective brake factors. However, this would be appropriate only for an 
EV without ABS that is braked only electrically, and NHTSA is unaware 
that any such configuration is planned for production. Thus, there 
appears to be no present need for the agency to give further 
consideration to this issue. If and when an all electric-braked vehicle 
without ABS is planned for production, the agency could revisit this 
issue. However, NHTSA believes that it would not be appropriate to 
expend extensive agency resources to accommodate a vehicle design that 
in all probability will never be built.
    Similarly, for a vehicle equipped with RBS that is not under the 
control of ABS, the adhesion utilization of the vehicle would be 
affected by the RBS in a manner that would be dependent on the state of 
charge of the vehicle's batteries. For such a vehicle, the torque wheel 
method of calculating adhesion utilization curves that is in Standard 
No. 135 would not be directly applicable. The most recent draft of 
proposed ECE Regulation 13-H would require, for such a vehicle, that 
the adhesion utilization provisions be met under the conditions of both 
minimum and maximum regenerative braking. While the agency agrees in 
concept with this approach, Regulation 13-H does not specify any 
detailed method for obtaining the adhesion utilization curves as 
Standard No. 135 does. NHTSA believes that a research program would be 
necessary to develop modifications to the present procedures to 
accommodate the effects of RBS, but, similar to the all electric-braked 
issue, questions whether such a vehicle would ever be built. Therefore, 
requirements to accomodate such a system are not included in this 
notice. The agency requests comments on whether any manufacturer has 
plans to produce an electric vehicle that is equipped with RBS that is 
part of the service brake system but that is not also equipped with 
ABS. At present, the agency is not aware of any such plans, and does 
not believe it would be appropriate to expend limited agency resources 
to develop requirements for a design that will in all probability never 
be built. If any manufacturer does foresee such a vehicle being built, 
the agency solicits comments on what would be appropriate adhesion 
utilization test procedures for such a vehicle.
    The reader will find that provisions of this FSNPRM not discussed 
by this notice are substantially the same as those proposed by Notice 
7.

Proposed Effective Date

    It is tentatively found for good cause shown that an effective date 
earlier than 180 days after issuance of the final rule would be in the 
public interest, and it is proposed that the effective date would be 30 
days after publication of the final rule.

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 
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 would 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 would 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 

[[Page 49549]]
hydrocarbon emissions and do not depend directly upon fossil fuels to 
propel them.

Executive Order 12778 (Civil Justice Reform)

    This proposed rule would 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.

Comments

    Interested persons are invited to submit comments on the FSNPRM. It 
is requested but not required that 10 copies be submitted.
    All comments must not exceed 15 pages in length. (49 CFR 553.21). 
Necessary attachments may be appended to these submissions without 
regard to the 15-page limit. This limitation is intended to encourage 
commenters to detail their primary arguments in a concise fashion.
    If a commenter wishes to submit certain information under a claim 
of confidentiality, three copies of the complete submission, including 
purportedly confidential business information, should be submitted to 
the Chief Counsel, NHTSA, at the street address given above, and seven 
copies from which the purportedly confidential information has been 
deleted should be submitted to the Docket Section. A request for 
confidentiality should be accompanied by a cover letter setting forth 
the information specified in the agency's confidential business 
information regulation. 49 CFR Part 512.
    All comments received before the close of business on the comment 
closing date indicated above for the proposal will be considered, and 
will be available for examination in the docket at the above address 
both before and after that date. To the extent possible, comments filed 
after the closing date will also be considered. Comments received too 
late for consideration in regard to the final rule will be considered 
as suggestions for further rulemaking action. Comments on the proposal 
will be available for inspection in the docket. The NHTSA will continue 
to file relevant information as it becomes available in the docket 
after the closing date, and it is recommended that interested persons 
continue to examine the docket for new material.
    Those persons desiring to be notified upon receipt of their 
comments in the rules docket should enclose a self-addressed, stamped 
postcard in the envelope with their comments. Upon receiving the 
comments, the docket supervisor will return the postcard by mail.

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, it is proposed that 49 CFR part 
571 be amended as follows:
    1. The authority citation for part 571 would continue to read as 
follows:

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

    2. Section 571.105 would be 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'' 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. Revising S5.5;
    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); and
    j. Adding S7.9.5 and S7.9.6.
    The revised and added heading and paragraphs would read as follows:


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

    S1. Scope. This standard specifies requirements for hydraulic and/
or electric service brake systems and associated parking brake systems.
* * * * *
    S3. Application. This standard applies to passenger cars, 
multipurpose passenger vehicles, trucks, and buses with hydraulic and/
or electric service brake systems.
    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.
* * * * *
    Regenerative braking system or RBS means an electrical energy 
system that is installed in an EV for recovering 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.
* * * * *
    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.
* * * * *
    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 

[[Page 49550]]
    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.
* * * * *
    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. In the 
event of 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, the propulsion batteries are at a state of charge of not less 
than 95 percent. During each burnish procedure, the propulsion 
batteries are restored to 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 
during a particular 40-stop increment only if the EV is incapable of 
achieving the initial burnish test speed during that increment. During 
each burnish procedure, the propulsion batteries may be charged by an 
external means or replaced by batteries that are at 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, an EV's propulsion 
batteries are at a state of 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). No further 
charging of the propulsion batteries occurs during any of the 
performance tests in the test sequence of this standard.
    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 the vehicle has no ``neutral'' transmission position. This RBS is 
operational during all burnishes and all tests, except for the test of 
a failed RBS. If the level of retardation provided by this RBS is 
subject to control by the driver (other than through the service brake 
control), it is set to produce the maximum regenerative braking effect 
during the burnishes, and the minimum regenerative braking effect 
during the test procedures.
    (b) If the RBS is not part of the service brake system, it is 
operational and set to produce the maximum regenerative braking effect 
during the burnishes, and is disabled during the test procedures.
    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 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. An auxiliary means may be used to 
accelerate an EV to test speed. The tests in S6.2.6 are conducted after 
completing the tests in S6.2.3.
    (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 two percent and not less than one percent above 
the EV actual automatic shut-down critical value. The critical value is 
determined by measuring the state-of-charge of the propulsion 
battery(s) 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 not more than two percent and not less than one 
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(s) that provides 
electrical energy to operate the electrically-actuated service brakes, 
the auxiliary battery(s) is at not more than two percent and not less 
than one 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 

[[Page 49551]]
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.
    3. Section 571.135 would be amended by:
    a. Revising the definitions of ``backup system'', ``maximum 
speed'', and ``split service brake system'' in S4, and adding in S4, in 
alphabetical order, definitions for ``Electric vehicle'' and 
``Regenerative braking system'';
    b. Adding S5.1.3;
    c. Revising the introductory text of S5.4.3 and S5.5.1 and adding 
S5.5.1 (e), (f), and (g);
    d. Revising the introductory text of S5.5.5(d);
    e. Adding S6.3.11, S6.3.12, and S6.3.13;
    f. Revising S7.10, S7.10.3(f), and S7.10.4;
    g. Adding S7.11.3(m); and
    h. Revising S7.12.2(i).
    The revised and added paragraphs would read as follows:


Sec. 571.135  Standard No. 135; Passenger Car 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.
* * * * *
    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.
* * * * *
    Regenerative braking system or RBS means an electrical energy 
system that is installed in an EV for recovering 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.
    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 the vehicle has no ``neutral'' 
transmission position.
    (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.
* * * * *
    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, the propulsion batteries are at a state 
of charge of not less than 95 percent. During the 200-stop burnish 
procedure, the propulsion batteries are restored to a state of charge 
of not less than 95 percent 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 

[[Page 49552]]
(S7.2 through S7.17 of this standard), unless otherwise specified, an 
EV's propulsion batteries are at a state of 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). 
No further charging of the propulsion batteries occurs during any of 
the performance tests in the test sequence of this standard.
    S6.3.12  State of charge of batteries for electrically-actuated 
service brakes. A vehicle equipped with electrically-actuated service 
brakes also performs the tests specified in S7.2 through S7.17 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 conditions (a), (b), or (c) as appropriate. An auxiliary 
means may be used to accelerate an EV to test speed. The tests in 
S6.3.12 are conducted after completing the tests in S6.3.11.3.
    (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 two percent and not less than one percent above 
the EV actual automatic shut-down critical value. The critical value is 
determined by measuring the state-of-charge of the propulsion 
battery(s) 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 not more than two percent and not less than one 
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 an auxiliary battery(s) that provides 
electrical energy to operate the electrically-actuated service brakes, 
the auxiliary battery(s) is at not more than two percent and not less 
than one 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.
    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. If the level of retardation 
provided by this RBS is subject to control by the driver (other than 
through the service brake control), it is set to produce the maximum 
regenerative braking effect during the burnish, and the minimum 
regenerative braking effect during the test procedures.
    (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.
    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), and after activation of the 
brake system indicator as specified in S5.5.1 of this standard, 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: September 19, 1995.
Barry Felrice,
Associate Administrator for Safety Performance Standards.
[FR Doc. 95-23689 Filed 9-25-95; 8:45 am]
BILLING CODE 4910-59-P