Federal Motor Vehicle Safety Standards; Stability and Control of Medium and Heavy Vehicles During Braking |
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Topics: Federal Motor Vehicle Safety Standards
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Ricardo Martinez
National Highway Traffic Safety Administration
March 16, 1998
[Federal Register: March 16, 1998 (Volume 63, Number 50)]
[Rules and Regulations]
[Page 12660-12664]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr16mr98-39]
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DEPARTMENT OF TRANSPORTATION
National Highway Traffic Safety Administration
49 CFR Part 571
[Docket No. NHTSA-98-3387]
RIN 2127-AF96
Federal Motor Vehicle Safety Standards; Stability and Control of
Medium and Heavy Vehicles During Braking
AGENCY: National Highway Traffic Safety Administration (NHTSA), DOT.
ACTION: Final rule; petitions for reconsideration.
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SUMMARY: This document responds to petitions for reconsideration of
final rules that amended Standard No. 105, Hydraulic Brake Systems, to
require medium and heavy vehicles to be equipped with an antilock brake
system (ABS). In response to the petitions, this document permits
hydraulically-braked vehicles with a gross vehicle weight rating (GVWR)
greater than 10,000 pounds but less than 19,501 pounds to be equipped
with a single wheel speed sensor in the driveline to control wheel
[[Page 12661]]
slip at the drive axle and permits rear tag axles to lock up.
Additionally, this document allows motor homes with a GVWR of 22,500
pounds or less to use a single rear drive axle wheel speed sensor if
they are manufactured before March 1, 2001, after which date new motor
homes must meet the same ABS requirements as other hydraulically-braked
trucks and buses.
DATES: Effective Dates: The amendments to 49 CFR 571.105 are effective
March 1, 1999. Petitions for Reconsideration: Any petition for
reconsideration of this rule must be received by NHTSA no later than
April 30, 1998.
ADDRESSES: Petitions for reconsideration of this rule should refer to
the above referenced docket numbers and should be submitted to:
Administrator, National Highway Traffic Safety Administration, 400
Seventh Street, S.W., Washington, D.C. 20590.
FOR FURTHER INFORMATION CONTACT: Mr. Samuel Daniel, Jr., Office of
Crash Avoidance Standards, National Highway Traffic Safety
Administration, 400 Seventh Street, SW., Washington, D.C. 20590;
Telephone (202) 366-4921, Fax (202) 366-4329.
SUPPLEMENTARY INFORMATION:
Table of Contents
I. Background
II. Petitions for Reconsideration of the December 1995 Final Rule
III. NHTSA's Response to Petitions for Reconsideration Related to
Standard No. 105
A. Control of Rear Wheel Slip
B. Application of ABS to Non-Powered, Rear Tag Axles
C. ABS Malfunction Lamp Activation Protocol
I. Background
Section 4012 of the Motor Carrier Act of 1991 1 directed
the Secretary of Transportation to initiate rulemaking concerning
methods for improving the braking performance of new commercial motor
vehicles, including trucks, tractors, trailers, and dollies. Congress
specifically directed that such a rulemaking examine antilock systems,
means of improving brake compatibility, and methods of ensuring
effectiveness of brake timing. The Act required that the rulemaking be
consistent with the Motor Carrier Safety Act of 1984 (49 U.S.C. 31136)
and be carried out pursuant to, and in accordance with the National
Traffic and Motor Vehicle Safety Act of 1966.2
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\1\ The Motor Carrier Act is part of the Intermodal Surface
Transportation Efficiency Act (ISTEA) of 1991, Pub. L. 102-240.
\2\ Now codified as 49 U.S.C 30101 et seq. (Safety Act)
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On March 10, 1995, NHTSA issued final rules requiring medium and
heavy vehicles 3 to be equipped with an antilock brake
system (ABS) to improve their directional stability and control during
braking. (60 FR 13216, 60 FR 13297) These final rules also reinstated
stopping distance requirements for air-braked heavy vehicles and
established stopping distance requirements for hydraulically-braked
heavy vehicles. In addition to the ABS requirement, the March 1995
final rule specified requirements about the electrical powering of
trailer ABS and ABS malfunction indicators. In response to petitions
for reconsideration of these requirements, NHTSA published a final rule
that affirmed its decision to require these features. (60 FR 63965,
December 13, 1995).
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\3\ The document uses the term heavy vehicles to refer to medium
and heavy vehicles.
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II. Petitions for Reconsideration of the December 1995 Final Rule
NHTSA received petitions for reconsideration of the December 1995
amendments to the final rule from the American Trucking Associations
(ATA), which represents trucking fleets, the National Private Truck
Council (NPTC), which represents private trucking fleets, the Truck
Manufacturers Association (TMA) 4, which represents truck
manufacturers, the Truck Trailer Manufacturers Association (TTMA),
which represents trailer manufacturers, the Heavy Duty Brake
Manufacturers Council (HDBMC) 5, which represents heavy duty
brake component manufacturers, Midland-Grau, Kelsey-Hayes, Rockwell
WABCO, Vehicle Enhancement Systems (VES), AlliedSignal, General Motors
(GM), Ford, and the Recreational Vehicle Industry Association (RVIA).
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\4\ TMA member companies include Ford, Freightliner, General
Motors, Mack Trucks, Navistar International, PACCAR, and Volvo GM
Heavy Truck.
\5\ HDBMC member companies include Abex, AlliedSignal, Eaton,
Midland-Grau, Ferodo America, Haldex, Lucas, MGM Brakes, Motion
Control/Carlisle, Rockwell, Rockwell WABCO, and Spicer/Dana.
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Most of the petitions focused on issues associated with Standard
No. 121's requirements on the electrical powering of trailer ABS and
the in-cab display of trailer ABS malfunctions. Those issues were
addressed in a final rule published on February 15, 1996. (61 FR 5949)
Petitions submitted by Ford, GM, Kelsey-Hayes, and RVIA addressed
issues associated with Standard No. 105, including the control of rear
wheel slip, the application of ABS to non-powered rear tag axles, and
the ABS malfunction lamp protocol. The February 1996 final rule stated
that it was deferring a response to these petitions because they
addressed issues associated with Standard No. 105. Today's notice
addresses the concerns raised by those petitioners.
III. NHTSA's Response to Petitions for Reconsideration Related to
Standard No. 105
A. Control of Rear Wheel Slip
In the March 1995 final rule, NHTSA required that each
hydraulically-braked vehicle with a GVWR greater than 10,000 pounds be
``equipped with an antilock brake system that directly controls the
wheels of at least one front axle and the wheels of at least one rear
axle of the vehicle.''
In the December 1995 final rule that responded to petitions for
reconsideration from Chrysler, Kelsey-Hayes, and the American
Automobile Manufacturers Association (AAMA), NHTSA amended Section
S5.5.1 by adding the following provision: ``On each vehicle with a GVWR
greater than 10,000 pounds but not greater than 12,000 pounds, the
antilock brake system may also directly control the wheels of the drive
axle by means of a single sensor in the driveline.'' Chrysler stated
that all its pickup trucks in the 10,000-12,000 pound GVWR class had
successfully used the driveline wheel speed sensor arrangement.
Notwithstanding NHTSA's decision to allow this sensing arrangement on
hydraulically-braked trucks up to 12,000 pounds, the agency emphasized
that such an arrangement would not be appropriate for heavier air-
braked trucks, because greater braking efficiency is typically required
at the rear wheels of such air-braked vehicles than on medium vehicles.
This is because air-braked vehicles typically are heavier and have
greater load carrying capacity.
In response to the December 1995 final rule, GM, Ford, and Kelsey-
Hayes asked NHTSA to revise section S5.5.1 of Standard No. 105. Ford
first requested that the 12,000-pound limit allowing driveline wheel
speed sensors be raised to 17,500 pounds and then to 20,500 pounds.
Kelsey-Hayes requested a 17,500-pound limit for driveline sensors. GM
requested a 16,500-pound limit; that company also cited the April 1995
AAMA petition for reconsideration requesting that the agency either
exempt all hydraulically-braked vehicles from the requirement for two
independent rear wheel sensors, or exempt all hydraulically-braked
vehicles under
[[Page 12662]]
16,500 pounds GVWR from the ABS mandate.
Each petitioner stated that the 12,000-pound limit for allowing
driveline sensors was not high enough to include their medium trucks
that have the same type of driveline sensor as Chrysler's sensor. Ford
stated that its F-Series chassis, including the F-350, the E-350, and
the E-Super duty vehicles have GVWRs up to 11,000, 12,500, and 14,050
pounds, respectively. GM stated that its GMC Sierra 3500 HD chassis cab
and the Chevrolet 3500 HD chassis cab can be configured to GVWRs up to
15,000 pounds, while its P-30 forward control chassis will soon be
available up to 16,500 pounds GVWR. Kelsey-Hayes stated that it has
supplied a single driveline sensor to GM since 1992 for use on trucks
with GVWRs up to 17,500 pounds.
In June 1996, GM and Ford 6 supplemented their January
1996 petitions for reconsideration, with additional information about
driveline sensors. They asked that the upper GVWR limit be eliminated
completely and that all ABS-equipped hydraulically-braked vehicles,
regardless of GVWR, be allowed to have a single sensor in the driveline
to control wheel slip at both rear wheels. In support of their
position, GM and Ford tested a light duty truck that was configured and
equipped to have a 20,500 pound GVWR. The truck was fitted with a
three-sensor, three-modulator (3S/3M) ABS that uses a single driveline
rear wheel speed sensor. The vehicle was lightly loaded to 8838 pounds
(the worst case condition) and subjected to a 30-mph brake-in-a-curve
test similar to, but more stringent than Standard No. 121's brake-in-a-
curve test for air-braked truck tractors. The petitioner's testing was
more stringent given that it was conducted on a curve with a lower
radius of curvature ( a 420-foot radius curve rather than a 500-foot
one), and on a slippier road surface (a surface with a 0.39 peak
friction coefficient (PFC) rather than a 0.50 PFC one). The testing
indicated that the single driveline sensor provided an acceptable
reading of the individual rear wheel speeds, resulting in the vehicle
remaining stable and within the lane throughout the test.
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\6\ Kelsey-Hayes and RVIA have stated their concurrence with
this position.
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NHTSA agrees with the petitioners that these test results
demonstrate that a 3S ABS with a single rear driveline sensor provides
satisfactory safety performance for medium duty hydraulically-braked
vehicles. The agency has added the term ``rear'' to the sentence in
S5.5.1 addressing ABS requirements to assure that a single drive axle
sensor is not installed on a front driveline axle. However, the agency
is not willing to eliminate the GVWR limit since there are
hydraulically-braked trucks with a GVWR in excess of 26,000 pounds and
the petitioners provided no 3S ABS braking stability and control test
data to support the allowance of 3S ABS for these trucks. The
petitioners' test results indicate that the braking stability and
control of hydraulically-braked trucks with relatively high GVWRs, up
to 20,500 pounds, is not compromised if a manufacturer uses an ABS
control strategy that employs a single rear driveline wheel speed
sensor in lieu of a control strategy employing direct control of each
individual rear wheel.
Accordingly, this rule permits 3S ABS on hydraulically-braked
vehicles up to 19,500 pounds GVWR, a breakpoint in the existing vehicle
weight class system used by State vehicle inspectors and the trucking
industry generally. A GVWR of 19,500 pounds, the upper limit of Class
5, will avoid introducing a unique breakpoint for this 3S ABS
requirement that differs from the breakpoints used for other regulatory
requirements. The 19,500-pound GVWR limit chosen for this requirement
is also slightly less than the test weight of the vehicle used in
braking stability and control tests cited by the petitioners.
By allowing 3S ABS on hydraulically-braked vehicles up to 19,500
pounds GVWR, NHTSA has addressed almost all the concerns expressed by
the petitioners. However, the American Automobile Manufacturers
Association (AAMA) provided additional information in a letter and
videotape forwarded to the agency on July 29, 1997. The tape shows a
motor home with a GVWR of 22,500 pounds ballasted to 26,000 pounds (the
breakpoint for Class 6 vehicles) successfully completing braking-in-a-
curve testing similar to the braking stability and control testing
required in Standard No. 121 for truck tractors. This testing was
performed on dry asphalt and wet jennite by Kelsey-Hayes at its vehicle
development center. NHTSA staff followed this up by attending a
supplementary demonstration of motor home stability and control during
braking at General Motors' test track in November 1997.
The AAMA originally asked that these test results be used to permit
extending 3S ABS to all Class 6 hydraulically-braked vehicles (GVWR of
up to 26,000 pounds). However, when NHTSA asked for information about
what difficulties were posed by using the generally-required 4S ABS for
Class 6 vehicles, AAMA responded that the problems were for motor homes
only, not other Class 6 vehicles. GM provided information for its P-
chassis, which is used for 9,000 to 10,000 motor homes annually. The P-
chassis, which currently uses a 3S ABS, can be used to manufacture a
completed motor home with a 22,500-pound GVWR. GM will modify this
chassis to use a 4S ABS system, but the modifications won't be ready
for production chassis for a few years. In the meantime, GM would have
to stop offering this chassis for use by the motor home industry. Since
there are no substitute motor home chassis in this GVWR range that
offer 4S ABS, these vehicles would in effect be temporarily forced out
of the market. RVIA argued that this would be an unfair burden, because
these motor homes are produced in very limited quantities (9,000-10,000
per year) by small businesses. RVIA also argued that these vehicles are
generally driven only for vacationing and camping.
In response to these arguments and information, NHTSA believes it
is appropriate to allow motor homes with a GVWR greater than 19,500
pounds to use a 3S ABS system. To prevent the economic hardship of
forcing motor home manufacturers to discontinue production for a few
years until appropriate 4S ABS chassis are available, the agency will
allow 3S ABS motor homes for a limited period of time. However, NHTSA
has no information indicating any difficulties for vehicles other than
motor homes in the 19,500 to 26,000 pound GVWR range (Class 6 vehicles)
in meeting the 4S ABS requirements. Hence, all Class 6 vehicles other
than motor homes will be required to provide 4S ABS.
For the purposes of this 3S ABS rulemaking, NHTSA is defining the
term ``motor home'' the same way that term has been defined in Standard
No. 208. Thus, a ``motor home'' for purposes of Standard No. 105 will
mean ``a motor vehicle with motive power that is designed to provide
temporary residential accommodations, as evidenced by the presence of
at least four of the following facilities: cooking; refrigeration or
ice box; self-contained toilet; heating and/or air conditioning; a
potable water supply system including a faucet and a sink; and a
separate 110-125 volt electric power supply and/or an LP gas supply.''
NHTSA believes it can accommodate the needs of motor home
manufacturers while assuring that these vehicles will transition
quickly to the same braking systems as other vehicles in their GVWR
[[Page 12663]]
range for the following reasons. First, the GM P-chassis, with a GVWR
of 22,500 pounds, is the largest hydraulically-braked motor home
chassis to use a 3S ABS. Any greater capacity motor home chassis would
be newly designed. NHTSA believes it is reasonable to require newly
designed Class 6 chassis to use a 4S ABS system. Second, the motor home
industry needs a transition period to move from 3S ABS on Class 6
vehicles to 4S ABS on those vehicles. GM, the manufacturer of the P-
chassis, has stated to NHTSA that GM will move to install 4S ABS on
this vehicle in the next few years. Given these circumstances, NHTSA
will permit motor homes with a GVWR between 19,501 pounds and 22,500
pounds to use a 3S ABS system on vehicles manufactured before March 1,
2001. This will give GM and other motor home chassis manufacturers
three years to develop and install 4S ABS, thus minimizing the burden
on both vehicle chassis and motor home manufacturers. All new motor
homes manufactured on or after March 1, 2001 with a GVWR of more than
19,500 pounds will be required to provide the 4S ABS system required on
other vehicles.
Since 3S ABS will be allowed on motor homes with a GVWR between
19,500 pounds and 22,500 pounds, it is important that the incomplete
vehicle manufacturer of a chassis equipped with 3S ABS include in the
statement of specific conditions of final manufacturer (Part
568.4(a)(7)(ii)) that only if the completed vehicle is a motor home,
will it conform to the standard. Completed vehicles in the specified
GVWR range, other than motor homes, will not conform to the standard,
if the incomplete chassis is equipped with a 3S ABS.
B. Application of ABS to Non-Powered, Rear Tag Axles
In its January 29, 1996 petition, RVIA requested that the ABS
requirement not apply to hydraulically-braked motor homes with tag
axles and GVWRs greater than 10,000 pounds. Tag axles are non-liftable,
non-powered axles that are fitted, either in front of or behind the
rear axle of the vehicle, by the second-stage vehicle manufacturer. Tag
axles improve a vehicle's balance and increase its carrying capacity.
RVIA stated that there is no way to apply antilock capability to tag
axles added to a vehicle chassis by second-stage vehicle manufacturers,
such as RVIA members. RVIA stated that less than 3000 vehicles per
model year have a tag axle. It further stated that brake and tag axle
manufacturers are reluctant to design, develop, and test ABS systems
for such a limited application.
In its June 24, 1996 supplement to its original petition, RVIA
stated that it would support a requirement for ABS on hydraulically-
braked motor homes, provided that a single driveline rear wheel speed
sensor is permitted and that the no-wheel-lockup requirement did not
apply to tag axles. With respect to tag axles, RVIA cited tests
conducted by GM and Kelsey/Hayes on a GM P-30 motor home chassis with a
GVWR of 19,500 pounds. In the tests, the vehicle was lightly loaded
(16,500 pounds), and driven at a speed of 25 mph (75 percent of the
vehicle's maximum drive-through speed) through a 500-foot radius curve
on a wetted jennite surface. The vehicle was also tested fully loaded,
on a high to low coefficient of friction transition test (asphalt to
ice). While the vehicle's tag axle (which was not controlled by ABS)
locked when brakes were applied, the vehicle's ABS modulated the brakes
and wheel speeds on the vehicle's powered drive axle and its steering
axle. The vehicle remained stable and under control throughout both
stops, despite the fact that the tag axle's wheels were locked.
The agency has received many requests for clarification of the ABS
requirements for heavy-duty, single unit vehicles with regard to the
number of axles that require ABS sensors. For heavy-duty single unit
vehicles, the standard requires ABS control on only one rear axle,
regardless of the number of rear axles and regardless of whether the
axles are installed as a tag or pusher axle by a final stage
manufacturer. To clarify this, the agency has added a definition for
the term ``tandem axle,'' which means an arrangement of axles, drive or
non-drive, in close proximity to each other. Hence, if a manufacturer
chooses to install ABS on the drive axle of a tandem but not on the
non-drive (tag or pusher) axle, the wheel lock restrictions would still
be able to be met without ABS on the tag or pusher axle. The current
wheel lock restrictions allow any two wheels on a tandem axle
(including two wheels on the tag axle) to lock-up for any duration.
Based on the foregoing, and on the test results mentioned by RVIA, the
agency has determined that it is not necessary to equip a tag axle with
ABS to comply with the wheel lock restriction requirements. The agency
notes that, even though the tag axle wheels locked when the motor
home's brakes were applied, the vehicle remained stable within the
travel lane throughout the stopping maneuvers. As RVIA stated, tag
axles that are added to these type vehicles typically do not carry a
significant portion of the vehicle's overall weight. These
considerations indicate that there are no negative stability
consequences if such axles lock-up.
C. ABS Malfunction Lamp Activation Protocol
In its January 1996 petition for reconsideration, Kelsey-Hayes
requested that NHTSA reconsider the final rule's activation protocol
requirements for ABS malfunction warning lamps. That company requested
that the malfunction warning lamp be allowed to remain activated (i.e.,
``on'' or lighted) during a low speed drive away to verify that the
vehicle's wheel speed sensors were properly functioning.
NHTSA has decided not to amend the ABS activation lamp protocol.
The agency notes that in support of its request, Kelsey-Hayes did not
provide any new data or reasoning, beyond that which was available to
the agency prior to the issuance of the March 10, 1995 final rule. At
that time, the agency noted that it had considered all the information
available on this issue, and had concluded that standardization of the
activation protocol was warranted for the following reasons. First, a
standardized protocol would enable Federal and State safety inspection
personnel to determine the operational status of ABSs without having to
move the vehicle. Second, it would preclude confusion among heavy
vehicle drivers relative to how this type of lamp functions. Third,
standardization would be consistent with ECE requirements on this
subject and would, therefore, be consistent with the goal of
international harmonization. Given that there is no new information to
reverse its previous decision, the agency has decided not to modify the
activation protocol requirements.
IV. Rulemaking Analyses and Notices
A. Executive Order 12866 and DOT Regulatory Policies and Procedures
This notice has not been reviewed under Executive Order 12866.
NHTSA has considered the impacts of this rulemaking action and
determined that it is not ``significant'' within the meaning of the
Department of Transportation's regulatory policies and procedures. In
connection with the March 1995 final rules, the agency prepared a Final
Economic Assessment (FEA) describing the economic and other effects of
this rulemaking action. Summary discussions of those effects were
provided in the ABS final rule. For persons wishing to examine the full
analysis, a copy is in the docket.
[[Page 12664]]
The amendments in today's final rule do not make those effects any
more stringent, and in some respects, they make it easier for a
manufacturer to comply with them. Specifically, by allowing the use of
a single driveline sensor to control rear wheel speeds and allowing
wheels on tag axles to lock during testing, vehicle manufacturers will
have more flexibility to comply with the requirements of this rule and,
as a result, costs could be reduced.
B. Regulatory Flexibility Act
NHTSA has also considered the effects of both this final rule and
the original final rule under the Regulatory Flexibility Act. I hereby
certify that it will not have a significant economic impact on a
substantial number of small entities. Accordingly, the agency has not
prepared a final regulatory flexibility analysis.
NHTSA concluded that the March 1995 final rule had no significant
impact on a substantial number of small entities. Thus, today's final
rule, which could potentially reduce costs associated with the March
1995 final rule, will not have a significant economic impact on a
substantial number of small entities.
C. National Environmental Policy Act
NHTSA has analyzed this rulemaking action for the purposes of the
National Environmental Policy Act. The agency has determined that
implementation of this action will not have any significant impact on
the quality of the human environment.
D. Executive Order 12612 (Federalism)
NHTSA has analyzed this action under the principles and criteria in
Executive Order 12612. The agency has determined that this notice does
not have sufficient Federalism implications to warrant the preparation
of a Federalism Assessment. No State laws will be affected.
E. Civil Justice Reform
This final rule does not have any retroactive effect. Under 49
U.S.C. 30103, whenever a Federal motor vehicle safety standard is in
effect, a State may not adopt or maintain a safety standard applicable
to the same aspect of performance which is not identical to the Federal
standard, except to the extent that the State requirement imposes a
higher level of performance and applies only to vehicles procured for
the State's use. 49 U.S.C. 30161 sets forth a procedure for judicial
review of final rules establishing, amending or revoking Federal motor
vehicle safety standards. That section does not require submission of a
petition for reconsideration or other administrative proceedings before
parties may file suit in court.
List of Subjects in 49 CFR Part 571
Imports, Motor vehicle safety, Motor vehicles, Rubber and rubber
products, Tires.
In consideration of the foregoing, the agency is amending Standard
No. 105, Hydraulic Brake Systems in Title 49 of the Code of Federal
Regulations at Part 571 as follows:
PART 571--[AMENDED]
1. The authority citation for Part 571 continues to read as
follows:
Authority: 49 U.S.C. 322, 30111, 30115, 30117, and 30166,
delegation of authority at 49 CFR 1.50. CFR 1.50.
2. Section 571.105 is amended by adding the definitions of ``motor
home'' and ``tandem axle'' in S4 and by revising S5.5.1, to read as
follows:
Sec. 571.105 Standard No. 105; Hydraulic and electric brake systems.
* * * * *
S4. Definitions.
* * * * *
Motor home means a motor vehicle with motive power that is designed
to provide temporary residential accommodations, as evidenced by the
presence of at least four of the following facilities: cooking;
refrigeration or ice box; self-contained toilet; heating and/or air
conditioning; a potable water supply system including a faucet and a
sink; and a separate 110-125 volt electric power supply and/or an LP
gas supply.
* * * * *
Tandem axle means a group of two or more axles placed in close
arrangement one behind the other with the center lines of adjacent
axles not more than 72 inches apart.
* * * * *
S5.5.1 Each vehicle with a GVWR greater than 10,000 pounds, except
for any vehicle with a speed attainable in 2 miles of not more than 33
mph, shall be equipped with an antilock brake system that directly
controls the wheels of at least one front axle and the wheels of at
least one rear axle of the vehicle. On each vehicle with a GVWR greater
than 10,000 pounds but not greater than 19,500 pounds and motor homes
with a GVWR greater than 10,000 pounds but not greater than 22,500
pounds manufactured before March 1, 2001, the antilock brake system may
also directly control the wheels of the rear drive axle by means of a
single sensor in the driveline. Wheels on other axles of the vehicle
may be indirectly controlled by the antilock brake system.
* * * * *
Issued on: February 23, 1998.
Ricardo Martinez,
Administrator.
[FR Doc. 98-6522 Filed 3-13-98; 8:45 am]
BILLING CODE 4910-59-P