[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
