[Federal Register Volume 64, Number 244 (Tuesday, December 21, 1999)]
[Proposed Rules]
[Pages 71377-71388]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-32889]


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DEPARTMENT OF TRANSPORTATION

National Highway Traffic Safety Administration

49 CFR Part 571

[Docket No. 99-6550]
RIN 2127-AH16


Federal Motor Vehicle Safety Standards: Heavy Vehicle Antilock 
Brake System (ABS) Performance Requirement

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

ACTION: Notice of proposed rulemaking.

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SUMMARY: On March 10, 1995, NHTSA published a final rule amending the 
hydraulic and air brake standards to require medium and heavy vehicles 
to be equipped with antilock brake systems (ABS) to improve the 
directional stability and control of these vehicles during braking. We 
supplemented the ABS requirements for truck tractors with a braking-in-
a-curve performance test on a low-coefficient of friction surface, 
using a full brake application, in both the unloaded (bobtail) 
condition and with the tractor loaded to its gross vehicle weight 
rating (GVWR) using an unbraked control trailer. The braking-in-a-curve 
test was not applied to single-unit trucks or buses or to air-braked 
trailers because we had performed only limited testing of ABS-equipped 
single-unit vehicles. We stated that we would continue research on 
dynamic performance tests for single-unit trucks, buses, and trailers, 
and would consider applying performance test requirements to these 
vehicles in the future.
    The agency is now proposing to apply the braking-in-a-curve dynamic 
performance test requirement to single-unit trucks and buses that are 
required to be equipped with antilock braking systems. After issuing 
the March 1995 final rule, we tested several ABS-equipped single-unit 
trucks and buses equipped with both hydraulic and air

[[Page 71378]]

brakes. We tentatively conclude that the test results confirm that the 
braking-in-a-curve performance test requirement is practicable for 
those vehicles. Adopting this requirement would complement the ABS 
equipment requirements and stopping distance requirements. Taken 
together, these requirements would improve the ability of the affected 
vehicles to stop in a stable and controllable manner.

Dates: Comment closing date: You should submit your comments early 
enough to ensure that Docket Management receives them not later than 
February 22, 2000.

Addresses: You should mention the docket number of this document in 
your comments and submit them in writing to: Docket Management, Room 
PL-401, 400 Seventh Street, SW, Washington, DC, 20590.
    You may call Docket Management at 202-366-9324. You may visit the 
Docket from 10 a.m. to 5 p.m., Monday through Friday.

FOR FURTHER INFORMATION CONTACT:
    For non-legal issues, you may call Mr. Jeff Woods, Safety Standards 
Engineer, Office of Crash Avoidance Standards, Vehicle Dynamics 
Division at (202) 366-2720, and fax him at (202) 493-2739.
    For legal issues, you may call: Mr. Otto Matheke, Attorney-Advisor, 
Office of the Chief Counsel at (202) 366-2992, and fax him at (202) 
366-3820.
    You may send mail to both of these officials at National Highway 
Traffic Safety Administration, 400 Seventh St., SW, Washington, DC, 
20590.

SUPPLEMENTARY INFORMATION:

I. Background
II. Single-Unit Truck & Bus ABS Performance Testing
III. Proposed Braking-in-a-Curve Test for Single-Unit Trucks and 
Buses
    A. Air-braked Trailers Not Included
    B. Testing in the Loaded/GVWR Conditions
    C. Road Test Geometry
    D. Test Surface
    E. Test Speed
    F. Type of Brake Application
    G. Number of Test Stops
    H. Required Performance
    I. Lightly-Loaded Test Weight
    J. Loaded Test Weight
    K. Initial Brake Temperature
    L. Transmission Position
    M. Test Sequence
    N. Special Drive Considerations
IV. Intermediate and Final Stage Manufacturers
V. Benefits
VI. Costs
VII. Compliance Date
VIII. Rulemaking Analyses and Notices
    A. EO 12866 and DOT Regulatory Policies and Procedures
    B. Regulatory Flexibility Act
    C. Federalism
    D. National Environmental Policy Act
    E. Paperwork Reduction Act
    F. Unfunded Mandates
    G. Civil Justice Reform
IX. Comments

I. Background

    On December 18, 1991, Congress passed the Intermodal Surface 
Transportation Efficiency Act (ISTEA or Act), Pub. L. 102-240. Section 
4012 of the Act directed the Secretary of Transportation to initiate 
rulemaking for improving the braking performance of new commercial 
motor vehicles, i.e., those with GVWRs of over 26,000 pounds (lbs.), 
including truck tractors, trailers, and dollies. The Act directed that 
in that rulemaking, the agency examine antilock brake systems (ABS), 
means of improving brake compatibility, and methods of ensuring the 
effectiveness of brake timing.
    In response to that congressional mandate, we published an advance 
notice of proposed rulemaking (ANPRM) on June 8, 1992 announcing our 
interest in proposing improvements in the directional stability and 
control of heavy vehicles during braking (57 FR 24212). That notice 
requested comments on such issues as the occurrence of loss-of-control 
crashes; the availability and performance of systems to improve 
directional stability and control; anticipated performance 
requirements, test procedures, and equipment requirements; diagnostic 
equipment to ensure in-use functioning of the systems; and anticipated 
costs of such equipment. The notice also requested comments on whether 
to include vehicles with GVWRs between 10,000 and 26,000 lbs. in the 
rulemaking action.
    NHTSA received comments in response to the ANPRM from heavy vehicle 
manufacturers and users, brake manufacturers, safety advocacy groups, 
trade associations, state entities and individuals. Most agreed that we 
should take action to improve the stability and control of heavy 
vehicles during braking to reduce the number of loss-of-control 
crashes. Commenters also addressed the application of potential 
rulemaking to certain vehicles, test procedures, warning and diagnostic 
systems, an implementation schedule for the requirements, and the costs 
of the hardware.
    We next published a notice of proposed rulemaking (NPRM) on 
September 28, 1993 (58 FR 50738) to amend Federal Motor Vehicle Safety 
Standard (Standard) Nos. 105, Hydraulic brake systems (now titled 
Hydraulic and electric brake systems), and 121, Air brake systems, to 
require all air-braked and hydraulic-braked vehicles with GVWRs over 
10,000 lbs. to be equipped with ABS to improve the lateral stability 
and control of these vehicles during braking. The NPRM also proposed 
that the ABS requirement be supplemented by a braking-in-a-curve test 
on a low coefficient of friction surface using a full brake 
application.
    We published a final rule requiring ABS on hydraulic and air-braked 
medium and heavy vehicles on March 10, 1995 (60 FR 13216) (hereinafter 
referred to as the stability and control final rule). The ABS 
requirements included a braking-in-a-curve performance test on a low-
coefficient of friction surface for truck tractors only. The test 
includes a full brake application in both the unloaded (bobtail) 
configuration and with the tractor loaded to its GVWR, the latter using 
an unbraked control trailer.
    The braking-in-a-curve test was not applied to single-unit trucks, 
buses, or air-braked trailers at that time. Our Motor Vehicle Safety 
Research Advisory Committee's ABS Task Force had developed the braking-
in-a-curve test procedure only for truck tractors. Since neither the 
agency nor the Task Force had included single-unit vehicles in the test 
program up to that time, we decided that, in view of the limited 
available data with respect to such vehicles and the concerns expressed 
by the American Automobile Manufacturers Association and other 
commenters about this dynamic performance test, we would apply the 
braking-in-a-curve test to truck tractors only. We stated, however, 
that we would continue research on dynamic performance tests for 
single-unit vehicles and would consider applying performance test 
requirements to those vehicles at a future time 1 (see 
section II below for a discussion of the testing of single unit trucks 
and buses that gave rise to this rulemaking action).
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    \1\ The agency published two companion final rules on the same 
day, one to reinstate stopping distance requirements for air-braked 
medium and heavy vehicles (60 FR 13286) and another to implement 
stopping distance requirements for hydraulic-braked medium and heavy 
vehicles (60 FR 13297). The cost/benefit information used for the 
three final rules was based on NHTSA's Final Economic Assessment, 
Final Rules, FMVSS Nos. 105 & 121, Stability and Control During 
Braking Requirements and Reinstatement of Stopping Distance 
Requirements for Medium and Heavy Vehicles, published in February, 
1995.
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II. Single-Unit Truck and Bus ABS Performance Testing

    NHTSA conducted ABS testing of single-unit trucks and buses in 1996 
and 1997 at our Vehicle Research and Test

[[Page 71379]]

Center (VRTC) in East Liberty, OH 2. Five air-braked 
straight trucks and two hydraulic-braked buses, all equipped with ABS, 
were used in the tests to aid in determining if the braking-in-a-curve 
performance test for tractors could also be applied to single-unit 
vehicles. The vehicles were subjected to all the requirements of 
Standards No. 105 and No. 121, including the braking-in-a-curve 
performance tests.
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    \2\ DOT HS 808941, Single Unit Truck and Bus ABS Braking-In-A-
Curve Performance Testing, February 1999.
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    The braking-in-a-curve tests were conducted by first finding the 
maximum drive-through speed, then determining the maximum brake-through 
speed. Maximum drive-through speed is defined in Standard No. 121 as 
the fastest constant speed that a vehicle can be driven through at 
least 200 feet of curve arc length without departing the lane. Maximum 
brake-through speed is defined as the fastest speed at which a full 
brake application can be made while the vehicle is in the curve, 
without the vehicle departing the lane. Determination of the maximum 
brake-through speed provided data on the potential margin of compliance 
or non-compliance for the test vehicles. More than four stops for the 
braking-in-a-curve test were performed during the loaded and unloaded 
tests.
    The straight trucks were chassis-cabs without bodies or equipment 
that would normally be installed by a second-stage manufacturer. The 
vehicles were equipped with ABS systems that met the equipment 
requirements of Standard No. 121. In order to simulate the unloaded 
condition of completed vehicles, a 2,500 lb load frame was installed on 
the chassis cabs. The load frame, which is used to secure ballast to 
the vehicle for testing in the loaded condition, includes a built-in 
roll bar to protect the test driver in the event of rollover during the 
tests. The instrumentation for collecting the test data, and the test 
driver, added another estimated 250 pounds to the unloaded vehicle test 
weight. Tests were conducted with all fuel tanks and fluid reservoirs 
filled to normal capacity.
    To test the straight trucks in the loaded condition, we added steel 
and/or concrete weights to the load frame so that the total weight of 
the vehicles was in accordance with their GVWRs and the axle loads were 
in proportion with their GAWRs. For most of the vehicles, the loads 
were situated so that the centers of gravity of the loads were 32 
inches above the frame. This provided a ballast height which 
corresponded to the specification in Standard No. 121 that the control 
trailer used for truck tractor road tests have a ballast center of 
gravity height not more than 24 inches above the flat bed surface of 
the control trailer. The 32-inch load height for single unit trucks is 
eight inches higher than for truck tractors to account for the height 
from the tractor's frame rails to the top of the control trailer, due 
to the fifth wheel coupling arrangement. For two of the vehicles, 
however, we conducted additional tests in the fully loaded condition 
with the load elevated to the maximum height specified by the 
manufacturer in their final-stage manufacturer's guidelines. These two 
tests with elevated center of gravity loadings were conducted to give 
some indication of the effect center of gravity height has on braking 
performance in the braking-in-a-curve test.
    The two school buses were equipped with ABS systems that met the 
ABS equipment requirements of Standard No. 105 that became effective on 
March 1, 1999. Since they were complete vehicles, no load frame or 
ballast was added for tests in the unloaded condition. However, the 
test instrumentation and driver added approximately 250 pounds to the 
unloaded vehicle weight. In addition, all fuel tanks and fluid 
reservoirs were filled to normal capacity. The loaded tests on the two 
school buses were conducted by placing sand bags on the floor and seats 
of each bus such that the total vehicle weight was equal to its GVWR 
with the axle load in proportion with the vehicle's GAWR.
    The braking-in-a-curve tests were conducted on an asphalt surface 
that was coated with Jennite, a driveway sealer, and wetted using a 
water truck. A 12-foot-wide lane was marked with the center of the lane 
having a 500-foot radius of curvature. The lane was marked with traffic 
cones on both sides spaced at 20-foot intervals. The surface had a 
cross slope of one percent and approximately zero longitudinal slope. 
The peak coefficient of friction (PFC) of the surface during the time 
of the testing ranged from 0.34 to 0.41. The effect of the cross slope 
was such that the test condition was considered to be worst case, since 
all road testing may not be able to be conducted on a completely level 
road surface due to variability and water run-off design requirements. 
The effect of the lower PFC would also be considered a worst-case test 
condition.
    In conducting the tests, the driver was instructed to begin the 
test in the center of the lane and to steer as necessary to keep the 
vehicle within the lane. If any cones were hit, the vehicle was 
considered to have gone out of the lane. The maximum drive-through 
speed was determined by making passes through the lane at a constant 
speed and increasing or decreasing the speed slightly on each 
successive pass to determine the maximum speed at which the vehicle 
would remain within the lane. Once this speed was determined, two or 
three additional passes were made to verify that the speed determined 
was the maximum speed at which the vehicle would remain in the lane. 
Similarly, the maximum brake-through speed was determined by making 
successive stops, increasing the speed gradually each time, to find the 
maximum speed at which the vehicle would stay in the lane. For these 
stops, the brake was applied as rapidly as possible to a full pressure 
application or full travel condition and held until the end of the 
stop.
    The results of the testing at VRTC confirmed that the braking-in-a-
curve test is practicable, repeatable, and safe for single unit 
vehicles. Six of the seven vehicles tested met the performance 
requirements now in effect for tractors, i.e., they stayed in the lane 
in at least three out of four stops when subjected to maximum braking 
at 75 percent of the maximum drive-through speed. In fact, these six 
vehicles remained in the lane during all four stops at 75 percent of 
the drive-through speed, all with a large margin of compliance.
    The two trucks for which elevated center-of-gravity ballast height 
comparison tests were conducted showed that the increased height did 
not have much effect on the vehicle's performance compared with the 
lower, 32-inch ballast center-of-gravity height testing. The test 
driver commented that this test condition caused an unsettling feeling 
during the testing in the vehicle's roll stability. However, to 
observers watching the testing, there were no indications that the 
vehicles were nearing rollover, such as lifting of an inside tire.
    We note that the one vehicle that did not meet the 75 percent of 
drive-through speed requirements was equipped with heavy duty axles 
with GAWR ratings of 20,000 pounds for the steer axle and 30,000 pounds 
for the single drive axle. Paragraph S3(b) of Standard No. 121 provides 
that any vehicle with an axle that has a GAWR of 29,000 pounds or more 
is excluded from Standard No. 121. Therefore, this particular vehicle 
would not need to comply with the braking-in-a-curve test. If a 
manufacturer were to produce this vehicle to comply voluntarily with 
Standard No. 121, regardless of the exclusion for axles over 29,000 
pounds, additional ABS development would probably be necessary. We note 
also that

[[Page 71380]]

while this vehicle did not meet the proposed requirements when tested 
in the unloaded condition, it passed the tests in the loaded condition 
by staying in the lane in all four of the stops at 75 percent of the 
drive-through speed.

III. Proposed Braking-in-a-Curve Test for Single-Unit Trucks and 
Buses

    Based on the tests conducted at VRTC, NHTSA proposes a braking-in-
a-curve test for single-unit trucks and buses, similar to the stability 
and control performance test in effect for air-braked tractors. We 
propose slight modifications, however, to allow for the differences 
between tractors and single-unit vehicles and to accommodate vehicles 
with hydraulic braking systems. Specifics of the proposed test are 
provided in the following subsections.

A. Air-Braked Trailers Not Included

    NHTSA is not proposing at this time to apply performance test 
requirements to air-braked trailers. We have not conducted testing of 
trailers since the March 1995 final rules, but may resume research 
concerning trailer dynamic performance tests at a later date.

B. Testing in the Loaded/GVWR Conditions

    NHTSA proposes that the braking-in-a-curve test be conducted in 
both the lightly-loaded vehicle condition and with the vehicle loaded 
to GVWR. There are several reasons why we are proposing testing in both 
loading conditions. First, this would be consistent with the test 
procedure currently in place for tractors. Second, testing in the 
fully-loaded and empty conditions was specified in the stability and 
control final rule in order to fully evaluate the vehicle's braking 
performance at two extreme loading conditions. The intent was to 
determine the minimum number of test conditions that would provide a 
thorough evaluation of a vehicle's braking system. Third, we determined 
that these two loading conditions, evaluated in the single braking-in-
a-curve maneuver, provide a sufficient range of test conditions while 
still providing a minimum level of performance testing.
    The agency is aware of a discussion in the SAE Truck and Bus 
Vehicle Deceleration and Stability Subcommittee that braking-in-a-curve 
testing of medium and heavy vehicles is only needed in the lightly-
loaded condition. The discussion, which took place at the 1995 SAE 
Truck and Bus Exposition in Winston-Salem, N.C., centered around 
testing performed by member organizations of the subcommittee 
indicating that vehicles in the lightly-loaded test condition have a 
lower margin of compliance than vehicles tested in the loaded 
condition.
    Our testing at VRTC indicated the following for the seven vehicles 
tested with regard to the proposed 75 percent maximum brake-through to 
maximum drive-through test requirement: (a) Four vehicles had lower 
margins of compliance in the lightly-loaded tests than in the loaded 
tests; (b) two vehicles had the same margin of compliance in both the 
loaded and lightly-loaded tests; and (c) one vehicle had a higher 
margin of compliance in the lightly-loaded test than in the loaded 
test. These results indicate that in general, the lightly-loaded test 
condition is the most severe test. We note, however, that the margin of 
compliance was generally high for most of the vehicles tested. The 
intent of testing vehicles in both the lightly-loaded and GVWR 
conditions was to simulate the possible braking conditions and 
maneuvers likely to be encountered by vehicles operated on public 
roads, while minimizing the number of tests that would have to be 
conducted to certify compliance. Deleting the loaded-to-GVWR test 
condition would eliminate the range of test conditions resulting in a 
single, lightly-loaded test. Although we are not proposing to eliminate 
testing at GVWR, we welcome comments on this issue.

C. Road Test Geometry

    NHTSA proposes the same road test geometry now in effect for 
tractors, namely a 12-foot-wide lane with a 500-foot radius measured at 
the center of the lane. We consider this geometry to be representative 
of an exit ramp with a moderately sharp curve, a type of road that all 
vehicles could be expected to encounter at some time. One consideration 
in the use of this test geometry for single-unit vehicles is that the 
wheelbases of such vehicles can be longer than for tractors or of the 
control trailer kingpin-to-axle length. Since most heavy vehicles are 
equipped with a non-steering rear axle(s), the path of the rear axle of 
a single-unit truck during a slow-speed turning maneuver follows a 
smaller radius than the wheels on the front steer axle. The tests 
conducted at VRTC, which included testing vehicles with wheelbases 
ranging from 148 inches through 311 inches, did not indicate any 
problems with the inside wheels on the rear axle(s) running off the 
inside of the curve and departing the lane. We believe, therefore, that 
the 500-foot radius curve is large enough to avoid that problem during 
testing of single-unit vehicles.

D. Test Surface

    We propose a test surface having a PFC of 0.5, which is a low 
coefficient of friction surface representative of a wet, worn asphalt 
roadway. As we noted in the stability and control final rule, 
maintaining a test surface of 0.5 PFC may not always be possible. 
However, minor variations in the test surface are not expected to have 
a major effect on the performance of vehicles in the braking-in-a-curve 
test, since that test has no stopping distance requirements. We have 
also determined that specifying PFC test surfaces is more appropriate 
for both high and low-friction surface testing compared to the older 
method of specifying skid numbers. This is especially true for ABS-
equipped vehicles which, during maximum braking, are prevented from 
sustained wheel lockup. The testing conducted at VRTC confirmed that 
this is the case for the medium and heavy single-unit vehicles tested 
and that specifying a PFC of 0.5 is appropriate for the braking-in-a-
curve test.

E. Test Speed

    NHTSA proposes a test speed of 75 percent of the maximum drive-
through speed or 30 mph, whichever is lower, for the braking-in-a-curve 
test for single unit trucks and buses.
    The requirement for testing tractors at the lower value of either 
30 mph or 75 percent of the maximum drive-through speed resulted from 
the need to have sufficient vehicle speed to adequately evaluate the 
performance of an ABS-equipped braking system. The test speed needed to 
be limited, however, to ensure that the test procedure could be safely 
conducted. In addition, by conducting the maximum drive-through speed 
determination before the braking-in-a-curve test, the effects of slight 
variability in test surface friction would be minimized since the 
drive-through speed would be measured for each combination of test 
vehicle and test surface just prior to conducting the braking tests.
    All of the single-unit trucks and buses tested at VRTC had maximum 
drive-through speeds in both the empty and loaded conditions ranging 
between 32 and 37 mph. This range represents the maximum constant speed 
that the vehicle can be driven through 200 feet of curve arc (for a 
500-foot radius curve) without the driver's losing control and the 
vehicle's departing the lane. None of the vehicles was able to 
negotiate the curve at 40 mph, which would be the upper limit of the 
drive-through speed determination required for a braking strategy 
specified as the lower of 30

[[Page 71381]]

mph or 75 percent of maximum drive-through speed. Therefore, these 
speeds are sufficiently high to place the vehicles at their performance 
limit for cornering under this test condition. Further, conducting a 
maximum brake application at 75 percent of this speed is a rigorous 
test of ABS performance.
    The testing at VRTC also indicated that the test speeds were not so 
high as to pose an unreasonable risk to the test drivers or vehicles. 
When the vehicles did lose control during the determination of the 
maximum drive-through speed, the test drivers were able to regain 
control in a short time and bring the vehicle to a safe stop. The test 
vehicles were equipped with a roll bar in the event of vehicle rollover 
during testing. However, no rollovers occurred nor were there any 
indications of near-rollover, although as noted above, the testing with 
high-center-of-gravity loadings did result in an unsettling feeling for 
the test driver.

F. Type of Brake Application.

    NHTSA proposes a brake pedal force of 150 pounds that is to be 
achieved within 0.2 seconds from the initial application of force to 
the brake control and maintained for the duration of the stop.
    We stated in the stability and control final rule that the braking-
in-a-curve test evaluates vehicle stability and control during worst 
case braking applications in an aggressive or ``hard'' stop. In that 
scenario, full brake applications are more readily repeatable than 
``driver best effort'' brake applications. A full treadle brake 
application for air-braked tractors is defined in Standard No. 121 as 
the output pressure measured at any of the treadle valve output 
circuits reaching 85 psi within 0.2 seconds after the application is 
initiated, or, as amended in the December 1995 final rule, one in which 
maximum treadle travel is achieved within 0.2 seconds after the 
application is initiated. Since the actuation of air brakes in single-
unit vehicles is similar to that used in tractors, we consider this 
same approach to be valid for single-unit vehicles as well. The tests 
at VRTC confirmed that the minor differences in the service braking 
systems between tractors and the single-unit vehicles tested were not 
found to have an effect on the ability of achieving the 85 psi 
application within 0.2 seconds as measured at the treadle valve. We are 
aware that, because of the wide variety of single-unit vehicles, there 
may be vehicles that would not be able to achieve this application 
rate. In those cases, achieving maximum treadle travel within 0.2 
seconds would be considered sufficient to define a full brake 
application.
    Standard No. 105 does not currently include a definition of a full 
brake application for medium and heavy vehicles equipped with hydraulic 
braking systems. Performance requirements for the first effectiveness 
stop for school buses with GVWRs of over 10,000 lbs. and the second and 
third effectiveness stops for all vehicles with GVWRs of over 10,000 
lbs. do not include specifications for maximum brake pedal force during 
these tests. For the five fade and recovery stops that apply to 
vehicles with GVWRs of over 10,000 lbs., the maximum permissible pedal 
force is 150 lbs. during the first four of these stops. The water 
recovery test requirements also include a 150-lbs. maximum pedal force 
requirement during the first four stops. These tests do not require 
that the maximum pedal force be used nor do they specify an application 
rate. The spike stops required for vehicles with GVWRs of less than 
10,000 lbs. include a specification for a 200-lb. brake pedal 
application within 0.08 seconds, and is representative of a maximum 
braking condition such as a ``panic'' stop. However, this high level of 
pedal force may make it necessary to use a mechanical actuator to 
achieve and maintain the 200-lb. force. Since the purpose of the 
proposed braking-in-a-curve test for medium and heavy vehicles is to 
evaluate the stability and control during a ``hard'' stop, rather than 
specifically a ``panic'' stop, we tentatively conclude that a pedal 
force of 150 lbs. is sufficient to perform the braking-in-a-curve 
evaluation, without necessitating specialized test equipment. In 
addition, since the proposed test surface has a PFC of 0.5, which 
represents a slippery road surface, we tentatively conclude that the 
150 lbs. of pedal force is sufficient to cause instability and loss of 
control in many medium or heavy vehicles that are not equipped with 
ABS.
    The agency considers the proposed 0.2 seconds for achieving the 
150-lbs. brake pedal force to be sufficiently rapid to represent a hard 
stop in a medium or heavy vehicle equipped with hydraulic brakes, and 
practicable from the standpoint of conducting performance tests on 
these type vehicles. While the spike stop requirements for vehicles 
under 10,000 lbs. GVWR include achieving the pedal application force 
within 0.08 seconds, the heavier brake components typically used in 
medium and heavy vehicles equipped with hydraulic brakes may not be 
able to be actuated as rapidly as in light vehicles. Also, the 0.08 
second application rate for the spike stops in light vehicles is often 
achievable only with a mechanical brake pedal actuator. In all of the 
braking-in-a-curve tests conducted by VRTC on medium and heavy vehicles 
with both hydraulic and air brakes, the test driver applied the brakes 
to minimize test complexity. This may also slightly increase the 
application time needed compared to a mechanical brake pedal actuator.
    NHTSA is not proposing to specify the brake pedal application rate 
for medium and heavy vehicles equipped with hydraulic brakes to include 
a reference to maximum pedal travel, as is specified for air-braked 
vehicles. The brake pedals in hydraulic braking systems do not 
typically reach their physical limit of travel during ``hard'' or 
``panic'' stops. Therefore, we believe that specifying such a brake 
application rate strategy for hydraulic-braked vehicles would be 
inappropriate.

G. Number of Test Stops

    NHTSA proposes that in 4 consecutive stops, the required 
performance must be achieved in at least 3 of those stops.
    In the stability and control final rule, we required that tractors 
comply with the braking-in-a-curve test requirements during 3 
consecutive stops. In response to several petitions for 
reconsideration, we amended that requirement in the December 13, 1995 
final rule to include one additional stop in which compliance is not 
required. Thus, the requirement now is that tractors must comply with 
the braking-in-a-curve test requirements in 3 out of 4 consecutive 
stops. This allows for minor variability in the performance of the test 
driver.
    Earlier testing of ABS-equipped tractors showed that the ABS 
provided consistent performance in maintaining stability and control 
during the braking-in-a-curve test. Although one vehicle could not 
comply with the braking-in-a-curve test during the VRTC testing of ABS-
equipped straight trucks and buses, the vehicles that did stay in the 
lane during the test were able to do so consistently. We believe, 
therefore, that it is appropriate to include that same number of test 
stops for straight trucks and buses as we now require for tractors, 
namely that during 4 consecutive stops, the required performance must 
be met in at least 3 of those stops (see H below).

H. Required Performance

    NHTSA proposes to require that the test vehicle remain within a 12-
foot-wide lane during the braking-in-a-curve test.

[[Page 71382]]

    We believe that prescribing a 12-foot-wide lane during the braking-
in-a-curve test is an appropriate performance measure for single-unit 
trucks and buses. The lane width of 12 feet is representative of a 
typical travel lane on a typical U. S. hard-surface road. Therefore, we 
tentatively conclude that it is appropriate to require that vehicle 
control within a lane of that width be maintainable by a driver during 
hard braking.

I. Lightly-Loaded Test Weight

    NHTSA proposes that the braking-in-a-curve test in the lightly-
loaded condition be conducted at the curb weight of the vehicle plus up 
to 1,500 pounds, including the driver, instrumentation, and roll bar.
    As discussed above, the single-unit trucks tested at VRTC were 
chassis-cabs which had not been completed by the installation of a body 
or other equipment. In order to provide some additional weight to the 
chassis-cabs to better simulate an unloaded completed vehicle, a 2,500 
pound load frame was bolted directly to the frame rails of each test 
vehicle. This load frame was also used to secure ballast for tests 
conducted in the loaded condition. As noted above, we are aware of the 
discussion in the trucking industry, through the SAE Truck and Bus 
Vehicle Deceleration and Stability Subcommittee, as to what suitable 
weight should be used for a load frame for testing incomplete vehicles. 
We do not propose that any weight figure be specified in the stability 
and control requirements for Standard Nos. 105 and 121. We are aware of 
the wide variety of bodies and equipment that are installed on chassis-
cabs and the variability in the weight of that equipment. Selection of 
one weight for a load frame may be appropriate for one weight class of 
vehicle, but not for another. Thus, unlike the vehicles we tested at 
VRTC, we do not conduct compliance testing on incomplete vehicles. For 
the purposes of compliance testing, we will obtain completed vehicles 
and expect to test them at their curb weight, plus an allowance for 
test and safety equipment, as discussed below.
    The VRTC tests of buses in the unloaded configuration were 
performed on completed vehicles, so no additional weight, other than 
the driver and instrumentation, was added for the unloaded tests. The 
tests were conducted with the buses at curb weight with full fuel 
tanks. The combined weight of the test driver and instrumentation was 
approximately 250 pounds.
    A January 6, 1997 petition for rulemaking submitted by the Truck 
Manufacturers Association (TMA) to amend Standard No. 121 included, 
among other things, a request for an additional weight allowance for a 
rollbar of up to 1,000 pounds for the straight line stopping distance 
tests for tractors, trucks, and buses in the lightly-loaded condition. 
The rollbar is intended to provide driver protection in the event of a 
rollover that could occur while testing heavy vehicles in limit-
performance maneuvers. [The rollbar portion of the TMA petition was 
granted. In a notice published in the Federal Register on February 3, 
1999 we proposed allowing the use of a rollbar in compliance testing 
(64 FR 5259).] We believe that in order to provide adequate protection 
for test drivers, the same provision for a rollbar should be permitted 
for the braking-in-a-curve test for single-unit vehicles. Therefore, we 
propose that the braking-in-a-curve test in the lightly-loaded 
condition include the unloaded vehicle weight plus up to 1,500 pounds 
for driver, instrumentation, and a rollbar. The 1,500 lb figure is 
based on the existing definition of ``lightly-loaded vehicle weight'' 
for vehicles with GVWRs of over 10,000 lbs. and the 1,000 lbs. for a 
rollbar. That term is defined in S4 of Standard No. 105 as the unloaded 
vehicle weight plus up to 500 lbs., including driver and 
instrumentation. This weight provision need not be included for tests 
in the fully-loaded condition since the weight of these items would be 
included as part of the load.

J. Loaded Test Weight

    NHTSA proposes to use the existing definitions of ``loaded test 
weight'' in Standard Nos. 105 and 121 for the braking-in-a-curve tests 
for single-unit trucks and buses.
    The existing definitions, which are used for straight-line stopping 
distance tests required for loaded single-unit trucks and buses, 
specify that the vehicle be loaded to its GVWR in proportion to each 
GAWR. An exception is provided in Standard No. 105 for cases in which 
an axle weight in the unloaded condition already exceeds its 
proportional GAWR with the vehicle loaded to GVWR. In such cases, the 
vehicle is loaded only over the other axle(s) until the GVWR is 
reached.
    The loading requirements for tractors in Standard No. 121, 
applicable to both straight line stopping distance and braking-in-a-
curve tests, provide that the center of gravity height of the ballast 
shall be less than 24 inches above the fifth wheel of the tractor. This 
is a relatively low center of gravity loading that is used to evaluate 
the braking performance of loaded tractors during the braking-in-a-
curve test and minimizes the risk of vehicle rollover during the test. 
This loading condition also provides a uniform test condition for 
tractors so that results will be repeatable from one test to another.
    The loading of straight trucks during the braking-in-a-curve tests 
conducted at VRTC included a load frame and ballast with a combined 
center of gravity height of 32 inches above the frame rail of the 
chassis cab. This loading scheme was selected to adequately evaluate 
the braking performance of the trucks while minimizing the risk of 
rollover. The purpose of the braking-in-a-curve test is to evaluate the 
vehicle's yaw stability and the driver's ability to maintain steering 
control, not to evaluate the vehicle's roll stability. Therefore, a 
reasonable loading scheme with respect to load center of gravity height 
is needed to ensure the safety of the test procedure.
    As in the case with the unloaded single-unit truck and bus vehicle 
tests, we do not conduct compliance testing on incomplete vehicles in 
the loaded condition. Since there are many configurations of bodies and 
equipment used in the completion of single-unit trucks, including 
flatbeds, tankers, van bodies, dump bodies, rollbacks, mixers, etc., 
and other configurations of vehicles not based on typical chassis-cabs, 
such as step vans, motor homes, and certain fire trucks, we believe 
that it would not be possible to specify a loading scheme that would be 
applicable to all single-unit trucks and buses. We are aware of efforts 
by the SAE Truck and Bus Vehicle Deceleration and Stability 
Subcommittee to revise Recommended Practice (RP) J1626, Braking, 
Stability, and Control Performance Test Procedures for Air-Brake 
Equipped Trucks, to incorporate loading requirements which can be used 
for testing incomplete chassis-cabs. However, we do not expect that 
this RP will address testing of completed single-unit vehicles or 
incomplete/completed vehicles manufactured on other types of chassis. 
For many types of vehicles, we will need to develop suitable loading 
schemes on a case-by-case basis, depending on the vehicle type. For 
example, a passenger bus could be loaded using sand bags or other heavy 
objects placed in all passenger seating positions and on the floor or 
in cargo areas to achieve GVWR loading in proportion to the vehicle's 
GAWRs.

[[Page 71383]]

K. Initial Brake Temperature

    NHTSA proposes an initial brake temperature between 150 and 200 
degrees F.
    In the September 1993 NPRM, we proposed using a higher initial 
brake temperature range of 250 to 300 degrees F. The intent was to 
reduce the amount of time needed to conduct the road tests by reducing 
the amount of time that brakes would need to cool between stops. In 
general, comments on the proposed increased temperature range stated 
that the increased temperatures would necessitate design changes in the 
braking system by requiring more aggressive linings, and that this 
increased initial temperature range would not be consistent with 
testing that had been conducted in the past using the lower initial 
temperature range. These negative aspects of the proposed temperature 
range outweighed the small benefits in reduced testing time, so we 
retained the 150 to 200 degree initial brake temperature criteria. For 
those reasons, we believe that this initial temperature range is also 
appropriate for testing of single-unit trucks and buses for the 
braking-in-a-curve test.

L. Transmission Position

    NHTSA proposes that the braking-in-a-curve test for single-unit 
trucks and buses be conducted either with the vehicle's transmission 
placed in a neutral position or with the clutch pedal depressed. This 
technique minimizes the effects of engine and driveline retardation, 
which is necessary in order to solely evaluate the performance of the 
braking system without undue driveline influences. Although the effects 
of engine and driveline retardation can affect the stability of medium 
and heavy vehicles when operated on low coefficient of friction road 
surfaces, this is not the primary purpose of the braking-in-a-curve 
test. The proposed test condition also helps to ensure test 
repeatability and reproducibility.

M. Test Sequence

    NHTSA proposes that the braking-in-a-curve test for air-braked 
single-unit trucks and buses be conducted immediately after the burnish 
procedure as indicated in Table I of Standard No. 121, with the loaded 
tests followed by the unloaded tests. We further propose that the 
braking-in-a-curve test for hydraulic-braked single-unit trucks and 
buses be conducted immediately after the post-burnish brake adjustment 
in S7.4.2.2, with the loaded tests followed by the unloaded tests.
    We originally selected this test sequence for air-braked tractors 
so that vehicle stability during the braking-in-a-curve test could be 
checked early in the test sequence. In the final rule of December 13, 
1995, we amended the test sequence by placing both braking-in-a-curve 
tests immediately after the burnish for several reasons: (a) to allow 
test track wetting to be accomplished more efficiently; (b) to minimize 
ABS performance variability that might occur after tires are subjected 
to high-speed stopping distance tests on a high coefficient of friction 
surface; and (c) to minimize vehicle transfers for those manufacturers 
that use a different test site for ABS testing. The same sequence is 
being proposed in this notice. In addition, the loaded test is proposed 
to be conducted prior to the unloaded test, since the vehicle would 
already be fully-loaded immediately following the brake burnish.

N. Special Drive Considerations

    We propose that single-unit trucks and buses being tested in the 
braking-in-a-curve test under Standard No. 105 be subjected to the same 
road test provisions as are currently specified for trucks and buses in 
subsection S6.1 of Standard No. 121.
    Paragraph S6.1.11 specifies that vehicles with interlocking axles 
or front wheel drive systems which are engaged and disengaged by the 
driver be tested with such systems disengaged. As in the case of the 
transmission, the driveline effects of a front wheel drive or interaxle 
locking system on the performance of the vehicle in the braking-in-a-
curve test should be minimized to the extent possible. Since the road 
test conditions in Standard No. 105 do not include this provision, we 
propose the same provision under Standard No. 105 as under Standard No. 
121. We invite comments on this issue.

IV. Intermediate and Final Stage Manufacturers

    In the NPRM of September 28, 1993 and the stability and control 
final rule of March 10, 1995, we discussed the issue of certification 
to Standard Nos. 105 and 121 for vehicles manufactured in two or more 
stages. One concern was that final stage manufacturers would not be 
able to conduct the road testing for each type of vehicle they 
manufacture. We stated that in many cases the incomplete vehicle 
manufacturer could pass through certification to the final stage 
manufacturer if the final stage manufacturer adhered to specifications 
provided by the incomplete vehicle manufacturer, for example, by not 
exceeding the GAWRs, not altering any brake component, and keeping the 
center of gravity of the completed vehicle within a specified envelope.
    In cases for which pass-through certification was not available, 
such as vehicles built in one stage, the manufacturer could use 
engineering analysis, actual testing, or computer simulations to 
certify their vehicles. Moreover, a manufacturer need not conduct such 
testing or analysis itself, but could base its certification on the 
services of independent engineers and testing laboratories, or could 
join together through trade associations to sponsor testing or 
analysis. Finally, manufacturers could rely on testing and analysis by 
third parties, such as brake manufacturers, who typically perform 
extensive analyses and tests of their products. Based on these various 
options available to vehicle manufacturers, we do not believe that the 
proposed performance requirements pose any significant certification 
burdens for final stage manufacturers or other small manufacturers.
    Another concern was that the pass-through certification from an 
incomplete vehicle manufacturer could have design limitations that are 
so design restrictive that final stage manufacturers would not be able 
to readily adhere to them. As stated above, however, the testing at 
VRTC showed that varying the load height on the trucks being tested did 
not have an appreciable effect on the results of the braking-in-a-curve 
test. Therefore, based on the testing performed to date, we are not 
aware of any significant additional requirements that would be 
necessary as a result of implementing the braking-in-a-curve test for 
single-unit trucks and buses that would result in the pass-through 
certification becoming unduly restrictive for final stage 
manufacturers.

V. Benefits

    NHTSA published a detailed estimate of the costs and benefits of 
equipping medium and heavy vehicles with ABS in the February 1995 Final 
Economic Assessment (FEA) (see footnote 1 above). This FEA provided 
estimates for the reduction in fatal, injury-producing, and property-
damage-only (PDO) crashes by equipping medium and heavy vehicles with 
ABS and implementing/reimplementing straight line stopping distance 
requirements. It also provided a detailed analysis of the projected 
costs to consumers and vehicle manufacturers to meet the ABS 
requirements. The projected annual benefits of ABS were summarized for 
all medium and heavy vehicles as follows:
    1. 29,103 crashes prevented per year.
    2. 38,227 fewer vehicle involvements in PDO crashes.

[[Page 71384]]

    3. 15,900 to 27,413 vehicle occupant injuries prevented per year.
    4. 320 to 506 vehicle occupant fatalities prevented per year.
    5. $457,780,795 to $552,769,946 of property damage prevented.
    Table 6 on page V-12 of the FEA provides a breakdown of the 
estimated benefits of ABS for each vehicle type including combination 
vehicles, bobtail tractors, single-unit trucks, and buses. That table 
also shows the reduced fatalities, injuries, and PDO crash damage to 
other vehicles involved in crashes with these medium and heavy 
vehicles. The breakdown did not differentiate between single-unit 
trucks and buses equipped with air versus hydraulic braking systems. In 
general, the table indicates that for single-unit trucks and buses 
equipped with ABS, between 16 and 34 truck and bus occupant fatalities 
will be prevented each year, and between 79 and 117 fatalities among 
occupants of other vehicles will be prevented each year.
    The potential benefits of applying the braking-in-a-curve 
performance test to single-unit trucks and buses, compared with the 
benefits of solely requiring the ABS equipment portions in the 
respective safety standards, were not differentiated in the FEA nor for 
the purposes of this rulemaking action. The full benefits projected in 
the FEA are based on having both the equipment requirements and 
performance tests to ensure that ABS installed on medium and heavy 
vehicles performs with a maximum level of safety. The benefits 
projected in the FEA reflect the installation of antilock brake systems 
that were in use and on the road at the time of the analysis. We have 
since conducted ABS braking-in-a-curve tests, on six single-unit 
vehicles--four straight trucks and two buses--that are now required to 
have ABS installed. All these vehicles passed the performance 
requirements with a large margin of compliance. While we project no 
additional benefits by requiring these performance tests, they will 
help assure that minimum levels of safety are maintained.

VI. Costs

    In the February 1995 FEA, NHTSA provided an extensive evaluation of 
the estimated costs to vehicle manufacturers and consumers associated 
with requiring ABS on medium and heavy vehicles. The majority of costs 
to consumers were the increased purchase price of vehicles equipped 
with ABS, in-service costs to perform maintenance and repairs to the 
ABS, and lost revenue and increased fuel consumption due to the extra 
weight of the ABS equipment. The FEA also included the costs to vehicle 
manufacturers to comply with the ABS requirements and the stopping 
distance requirements in the companion final rule. Although specific 
costs were not identified for conducting the braking-in-a-curve test 
for tractors, the costs to vehicle manufacturers (excluding the cost 
for the ABS equipment which would be passed on to the consumer) for all 
medium and heavy vehicles to comply with the new stopping distance 
requirements were estimated as follows:

    Air-braked vehicles--Total cost of $11.71 million, including 
$6.0 million for compliance testing costs and $5.71 million related 
to vehicle modifications necessary to improve vehicle stopping 
distance performance. For the estimated 208,500 air-braked vehicles 
produced each year, the total estimated cost per vehicle for the 
first year after the final rules was $56. For the remaining years 
after the first year, the estimated cost per vehicle was $37.
    Hydraulic-braked vehicles--Total cost of $1.0 million, all for 
compliance testing. During the first year after the final rules, an 
estimated 194,400 vehicles would be affected for a cost per vehicle 
estimated at $5. In the years following the first year, the cost per 
vehicle was estimated at $2 per vehicle.

    The first-year costs are higher because the additional road test 
requirements imposed by the control and stability final rule and the 
stopping distance final rule would require compliance testing of all 
affected vehicles that are already in production, while in the later 
years, only new vehicle designs or vehicles with modifications to their 
braking systems would need to be tested. Complete compliance tests for 
both hydraulic-and air-braked vehicles were estimated to cost $5,000 
per vehicle per test.
    NHTSA provides the following estimates for the cost of implementing 
the braking-in-a-curve test for single-unit trucks and buses. A stand-
alone braking-in-a-curve test is estimated to cost $1500, and the 
incremental cost to incorporate the braking-in-a-curve test into a 
complete Standard No. 105 or 121 compliance test is estimated at 
$1,000.
    For air-braked single-unit vehicles: As shown in Table 13 of the 
FEA, an estimated 53,900 single-unit trucks and 7,000 buses would be 
affected annually. For all air-braked vehicles, including tractors, the 
FEA estimated that twelve medium and heavy vehicle manufacturers would 
need to conduct 100 compliance tests each, for a total of 1200 
compliance tests. If only single-unit trucks and buses are to be 
tested, there are fewer numbers of these vehicles produced compared to 
tractors, but there are more vehicle types that would need to be 
tested. We estimated, therefore, that the twelve manufacturers would 
need to conduct 60 compliance tests each, for a total of 720 tests, in 
the first year that the braking-in-a-curve test would become effective, 
at a cost of $1,080,00 (720  x  $1,500). This assumes that compliance 
testing for the stopping distance requirements would have already been 
conducted. The cost per air-braked vehicle is estimated to be about $18 
($1,080,000  60,900). In the later years, it is estimated that 
30 compliance tests would be required annually, for a total cost of 
$360,000 (12  x  30  x  $1,000). The cost per air-braked vehicle in the 
later years would be about $6 ($360,000  60,900).
    Hydraulic-braked single-unit vehicles: As shown in Table 13 of the 
FEA, an estimated 194,400 single-unit vehicles would be affected 
annually. Assuming that the timing of the braking-in-a-curve test is 
such that all of the affected vehicles would have this test requirement 
included in a complete compliance test to all of the requirements in 
Standard No. 105, the $1,000 per test cost is used. The estimates in 
the FEA were that 10 vehicle manufacturers would need to conduct 20 
compliance tests each, for a total of 200 compliance tests, at an 
annual cost of $200,000 (200  x  $1,000). The cost per vehicle is then 
estimated at about $1 ($200,000  194,400). This cost per 
vehicle would be the same in the later years.
    Implementing the braking-in-a-curve performance test for single-
unit vehicles with either hydraulic or air brakes is not expected to 
result in any increases in vehicle equipment or manufacturing costs, 
since these vehicles are already required to be equipped with ABS. As 
long as the antilock braking systems that are being installed on 
affected vehicles perform as they are supposed to, that is, preventing 
wheel lockup under a variety of road and load conditions, then these 
vehicles should be able to comply with the braking-in-a-curve test 
without additional development or equipment costs to the vehicle 
manufacturer. Thus all costs associated with requiring the braking-in-
a-curve test are limited to the cost of vehicle manufacturers 
performing road tests and do not include equipment costs.

VII. Compliance Date

    NHTSA proposes that the compliance date for the braking-in-a-curve 
test requirements, for both air and hydraulic-braked single unit trucks 
and buses, be two years after publication of the final rule in the 
Federal Register. Due to the operating conditions of these trucks, 
which often call for specialized designs, manufacturers produce a large

[[Page 71385]]

number of different truck configurations. The proposal would provide 
sufficient leadtime to ensure that the manufacturers can test a 
relatively large number of vehicle types and configurations. At the 
same time, it would also ensure that this important check of vehicle 
stability is implemented in a timely manner to ensure the safe 
operation of these vehicles. Optional early compliance would be 
permitted on and after the date of publication of the final rule in the 
Federal Register.

VIII. Rulemaking Analyses and Notices

A. Executive Order 12866 and DOT Regulatory Policies and Procedures

    This document has not been reviewed under Executive Order 12866, 
Regulatory Planning and Review.
    We have analyzed the impact of this rulemaking and have determined 
that it is not ``significant'' within the meaning of DOT's regulatory 
policies and procedures. This action proposes to amend the air and 
hydraulic brake standards applicable to medium and heavy vehicles to 
provide for a braking-in-a-curve test for single-unit trucks and buses 
to enhance the stability and control of those vehicles. As discussed in 
Section VII above, we estimate that the total cost of the braking-in-a-
curve test for manufacturers of single-unit vehicles equipped with air 
brakes would be approximately $1,080,000 the first year, for a per-
vehicle cost about $18. In the later years, we estimate that the per-
vehicle cost would be approximately $6, for a total cost of about 
$360,000. For hydraulic-braked single-unit vehicles, we estimate the 
annual cost to manufacturers of the braking-in-a-curve test to be about 
$200,000, for a per-vehicle cost of about $1. We estimate that this 
cost would be the same in the later years.
    As discussed above, NHTSA evaluated in detail the costs and 
benefits of equipping medium and heavy vehicles with ABS. We believe 
that the full array of costs and benefits discussed in the FEA will not 
be fully attained until 10 years or more since it will take that long 
until all existing non-ABS medium and heavy vehicles have been replaced 
by newer vehicles equipped with ABS. Accordingly, we believe that the 
projected figures in the FEA are still valid and on that basis, we have 
concluded that preparation of another full regulatory evaluation is not 
warranted.

B. Regulatory Flexibility Act

    NHTSA has considered the effects of this rulemaking action under 
the Regulatory Flexibility Act, 5 U.S.C. 601, et seq. I hereby certify 
that this notice of proposed rulemaking would not have a significant 
impact on a substantial number of small entities.
    The following is our statement providing the factual basis for this 
certification (5 U.S.C. 605(b)). The amendments proposed in this action 
would primarily affect manufacturers of medium and heavy vehicles, 
including single-unit trucks and buses. The Small Business 
Administration (SBA) regulation at 13 CFR part 121 defines a small 
business as a business entity that operates primarily within the United 
States (13 CFR 121.105(a)).
    SBA's size standards are organized according to Standard Industrial 
Classification (SIC) codes. SIC code No. 3711, Motor Vehicles and 
Passenger Car Bodies, prescribes a small business size standard of 
1,000 or fewer employees. SIC code No. 3714, Motor Vehicle Parts and 
Accessories, prescribes a small business size standard of 750 or fewer 
employees.
    The amendments proposed in this rulemaking add an additional test 
procedure to the air and hydraulic brake standards, applicable only to 
medium and heavy single-unit trucks and buses. These amendments do not 
apply to trailers. The amendments, if adopted, would impose minimal 
testing costs to manufacturers of the affected vehicles, most if not 
all of which would not qualify as small businesses under SBA 
guidelines. We estimate that the proposed amendments, if adopted, would 
result in minimal, if any, additional costs to small businesses or 
consumers. Accordingly, there would be no significant impact on small 
businesses, small organizations, or small units by these amendments. 
For those reasons, the agency has not prepared a preliminary regulatory 
flexibility analysis.

C. Executive Order No. 12612, Federalism

    NHTSA has analyzed this rulemaking action in accordance with the 
principles of E.O. 12612 and has determined that this rule does not 
have sufficient federalism implications to warrant preparation of a 
Federalism Assessment.

D. National Environmental Policy Act

    NHTSA has analyzed this rulemaking action for the purposes of the 
National Environmental Policy Act and has determined that 
implementation of this rulemaking action would not have any significant 
impact on the quality of the human environment.

E. Paperwork Reduction Act

    In accordance with the Paperwork Reduction Act of 1980, Pub L. 96-
511, NHTSA states that there are no information collection requirements 
associated with this rulemaking action.

F. Unfunded Mandates Reform Act

    The Unfunded Mandates Reform Act of 1995 (Pub L. 104-4) requires 
agencies to prepare a written assessment of the costs, benefits, and 
other effects of proposed or final rules that include a Federal mandate 
likely to result in the expenditure by state, local, or tribal 
governments, in the aggregate, or by the private sector, of more than 
$100 million annually. This proposed rule does not meet the definition 
of a Federal mandate because, if adopted, annual expenditures by the 
stated entities will not exceed the $100 million threshold.

G. Civil Justice Reform

    The amendments proposed in this rulemaking action would not have 
any retroactive effect. Under 49 U.S.C. 30103(b), whenever a Federal 
motor vehicle safety standard is in effect, a state or political 
subdivision of a state may prescribe or continue in effect a standard 
applicable to the same aspect of performance of a motor vehicle only if 
that standard is identical to the Federal standard. However, the United 
States government, a state or political subdivision of a state may 
prescribe a standard for a motor vehicle or motor vehicle equipment 
obtained for its own use that imposes a higher performance requirement 
than that required by the Federal standard. Section 30161 of Title 49, 
U.S. Code sets forth a procedure for judicial review of final rules 
establishing, amending or revoking Federal motor vehicle safety 
standards. A petition for reconsideration or other administrative 
proceeding is not required before parties may file suit in court.

IX. Comments

How Do I Prepare and Submit Comments?

    Your comments must be written and in English. To ensure that your 
comments are correctly filed in the Docket, please include the docket 
number of this document in your comments.
    Your comments must not be more than 15 pages long. (49 CFR 553.21). 
We established this limit to encourage you to write your primary 
comments in a concise fashion. However, you may attach necessary 
additional documents to your comments. There is no limit on the length 
of the attachments.

[[Page 71386]]

    Please submit two copies of your comments, including the 
attachments, to Docket Management at the address given above under 
ADDRESSES.

How Can I Be Sure That My Comments Were Received?

    If you wish Docket Management to notify you upon its receipt of 
your comments, enclose a self-addressed, stamped postcard in the 
envelope containing your comments. Upon receiving your comments, Docket 
Management will return the postcard by mail.

How Do I Submit Confidential Business Information?

    If you wish to submit any information under a claim of 
confidentiality, you should submit three copies of your complete 
submission, including the information you claim to be confidential 
business information, to the Chief Counsel, NHTSA, at the address given 
above under FOR FURTHER INFORMATION CONTACT. In addition, you should 
submit two copies, from which you have deleted the claimed confidential 
business information, to Docket Management at the address given above 
under ADDRESSES. When you send a comment containing information claimed 
to be confidential business information, you should include a cover 
letter setting forth the information specified in our confidential 
business information regulation. (49 CFR part 512.)

Will the Agency Consider Late Comments?

    We will consider all comments that Docket Management receives 
before the close of business on the comment closing date indicated 
above under DATES. To the extent possible, we will also consider 
comments that Docket Management receives after that date. If Docket 
Management receives a comment too late for us to consider it in 
developing a final rule (assuming that one is issued), we will consider 
that comment as an informal suggestion for future rulemaking action.

How Can I Read the Comments Submitted by Other People?

    You may read the comments received by Docket Management at the 
address given above under ADDRESSES. The hours of the Docket are 
indicated above in the same location.
    You may also see the comments on the Internet. To read the comments 
on the Internet, take the following steps:
     Go to the Docket Management System (DMS) Web page of the 
Department of Transportation (http://dms.dot.gov/).
     On that page, click on ``search.''
     On the next page (http://dms.dot.gov/search/), type in the 
four-digit docket number shown at the beginning of this document. 
Example: If the docket number were ``NHTSA-1998-1234,'' you would type 
``1234.'' After typing the docket number, click on ``search.''
     On the next page, which contains docket summary 
information for the docket you selected, click on the desired comments.
     You may download the comments. However, since the comments 
are imaged documents, instead of word processing documents, the 
downloaded comments are not word searchable.
    Please note that even after the comment closing date, we will 
continue to file relevant information in the Docket as it becomes 
available. Further, some people may submit late comments. Accordingly, 
we recommend that you periodically check the Docket for new material.

List of Subjects in 49 CFR Part 571

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

    In consideration of the foregoing, 49 CFR part 571 would be amended 
as follows:

PART 571--FEDERAL MOTOR VEHICLE SAFETY STANDARDS

    1. The authority citation for part 571 would continue to read as 
follows:

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

    2. Section 571.105 would be amended by adding definitions of ``Full 
brake application'' and ``Maximum drive-through speed'' to S4; by 
revising S5.1, S6.9.2 the introductory text of S7, S7.5, and Table I; 
and by adding S5.1.7 and S6.14, to read as follows:


Sec. 571.105  Standard No. 1059, Hydraulic brake and electric systems.

* * * * *
    S4  Definitions.
* * * * *
    Full brake application means a brake application in which the force 
on the brake pedal reaches 150 pounds within 0.2 seconds from the point 
of application of force to the brake control.
* * * * *
    Maximum drive-through speed means the highest possible constant 
speed at which the vehicle can be driven through 200 feet of a 500-foot 
radius curve arc without leaving the 12-foot lane.
* * * * *
    S5.1  Service brake systems. Each vehicle must be equipped with a 
service brake system acting on all wheels. Wear of the service brake 
must be compensated for by means of a system of automatic adjustment. 
Each passenger car and each multipurpose passenger vehicle, truck, and 
bus with a GVWR of 10,000 pounds or less must be capable of meeting the 
requirements of S5.1.1 through S5.1.6 under the conditions prescribed 
in S6, when tested according to the procedures and in the sequence set 
forth in S7. Each school bus with a GVWR greater than 10,000 pounds 
must be capable of meeting the requirements of S5.1.1 through S5.1.5, 
and S5.1.7 under the conditions specified in S6, when tested according 
to the procedures and in the sequence set forth in S7. Each 
multipurpose passenger vehicle, truck and bus (other than a school bus) 
with a GVWR greater than 10,000 pounds must be capable of meeting the 
requirements of S5.1.1, S5.1.2, S5.1.3, and S5.1.7 under the conditions 
specified in S6, when tested according to the procedures and in the 
sequence set forth in S7. Except as noted in S5.1.1.2 and S5.1.1.4, if 
a vehicle is incapable of attaining a speed specified in S5.1.1, 
S5.1.2, S5.1.3, or S5.1.6, its service brakes must be capable of 
stopping the vehicle from the multiple of 5 mph that is 4 to 8 mph less 
than the speed attainable in 2 miles, within distances that do not 
exceed the corresponding distances specified in Table II. If a vehicle 
is incapable of attaining a speed specified in S5.1.4 in the time or 
distance interval set forth, it must be tested at the highest speed 
attainable in the time or distance interval specified.
* * * * *
    S5.1.7  Stability and control during braking. When stopped four 
consecutive times under the conditions specified in S6, each vehicle 
with a GVWR greater than 10,000 pounds and manufactured on or after 
(COMPLIANCE DATE, if adopted) must stop from 30 mph or 75 percent of 
the maximum drive-through speed, whichever is less, at least three 
times within the 12-foot lane, without any part of the vehicle leaving 
the roadway. Stop the vehicle with the vehicle:
    (a) Loaded to its GVWR, and
    (b) At its unloaded weight, plus up to 500 pounds (including driver 
and instrumentation), or at the manufacturer's option, at its unloaded 
weight plus up to 500 pounds (including driver and instrumentation)

[[Page 71387]]

and plus not more than an additional 1000 pounds for a roll bar 
structure on the vehicle.
* * * * *
    S6.9.2 (a) For vehicles with GVWRs greater than 10,000 pounds, road 
tests are conducted on a 12-foot-wide, level roadway, having a peak 
friction coefficient of 0.9 when measured using an American Society for 
Testing and Materials (ASTM) E 1136 standard reference test tire, in 
accordance with ASTM Method E 1337-90, at a speed of 40 mph, without 
water delivery. Burnish stops are conducted on any surface. The parking 
brake test surface is clean, dry, smooth, Portland cement concrete.
    (b) For vehicles with GVWRs greater than 10,000 pounds, stability 
and control during braking tests are conducted on a 500-foot-radius 
curved roadway with a wet level surface having a peak friction 
coefficient of 0.5 when measured on a straight or curved section of the 
curved roadway using an American Society for Testing and Materials 
(ASTM) E1136 standard reference tire, in accordance with ASTM Method 
E1337-90, at a speed of 40 mph, with water delivery.
* * * * *
    S6.14 Special drive conditions. A vehicle with a GVWR greater than 
10,000 pounds equipped with an interlocking axle system or a front 
wheel drive system that is engaged and disengaged by the driver is 
tested with the system disengaged.
* * * * *
    S7. Test procedure and sequence. Each vehicle must be capable of 
meeting all the applicable requirements of S5 when tested according to 
the procedures and in sequence set forth below, without replacing any 
brake system part or making any adjustments to the brake system other 
than as permitted in the burnish and reburnish procedures and in S7.9 
and S7.10. For vehicles only having to meet the requirements of S5.1.1, 
S5.1.2, S5.1.3, and S5.1.7 in section S5.1, the applicable test 
procedures and sequence are S7.1, S7.2, S7.4, S7.5, S7.9, S7.10, S7.11 
and S7.18. However, at the option of the manufacturer, the following 
test procedure and sequence may be conducted: S7.1, S7.2, S7.3, S7.4, 
S7.5, S7.6, S7.7, S7.8, S7.9, S7.10, S7.11, and S7.18. The choice of 
this option must not be construed as adding to the requirements 
specified in S5.1.2 and S5.1.3. Automatic adjusters must remain 
activated at all times. A vehicle shall be deemed to comply with the 
stopping distance requirements of S5.1 if at least one of the stops at 
each speed and load specified in each of S7.3, S7.5, S7.8, S7.9, S7.10, 
S7.15 and S7.17 (check stops) is made within a stopping distance that 
does not exceed the corresponding distance specified in Table II. When 
the transmission selector is required to be in neutral for a 
deceleration, a stop or snub must be obtained by the following 
procedures:
    (a) Exceed the test speed by 4 to 8 mph;
    (b) Close the throttle and coast in gear to approximately 2 mph 
above the test speed;
    (c) Shift to neutral; and
    (d) When the test speed is reached, apply the service brakes.
* * * * *
    S7.5 (a) Stability and control during braking (vehicles with GVWRs 
greater than 10,000 pounds). Make four stops in the loaded condition 
specified in S5.1.7(a) and then four stops in the unloaded condition 
specified in S5.1.7(b). Use a full brake application for the duration 
of the stop, with the clutch pedal depressed or the transmission 
selector control in the neutral position, for the duration of each 
stop.
    (b) Service brake system--second effectiveness test. Repeat S7.3. 
Then (for passenger cars and other vehicles with GVWRs of 10,000 pounds 
or less) make four stops from 80 mph if the speed attainable in 2 miles 
is not less than 84 mph.
* * * * *

                             Table I--Brake Test Procedure Sequence and Requirements
----------------------------------------------------------------------------------------------------------------
                                              Test load
            Sequence             ----------------------------------     Test procedure          Requirements
                                       Light             GVWR
----------------------------------------------------------------------------------------------------------------
1. Instrumentation check........  ...............  ...............  S7.2
2. First (preburnish)             ...............               X   S7.3                   S5.1.1.1
 effectiveness test.
3. Burnish procedure............  ...............               X   S7.4                   .....................
4. Braking-in-a-curve test......               X                X   S7.5(a)                S5.1.7
5. Second effectiveness test....  ...............               X   S7.5(b)                S5.1.1.2
6. First reburnish..............  ...............               X   S7.6                   .....................
7. Parking brake................               X                X   S7.7                   S5.2
8. Third effectiveness (lightly                X   ...............  S7.8                   S5.1.1.3
 loaded vehicle).
9. Partial failure..............               X                X   S7.9                   S5.1.2
10. Inoperative brake power and   ...............               X   S7.10                  S5.1.3
 power assist units.
11. First fade and recovery.....  ...............               X   S7.11                  S5.1.4
12. Second reburnish............  ...............               X   S7.12                  .....................
13. Second fade and recovery....  ...............               X   S7.13                  S5.1.4
14. Third reburnish.............  ...............               X   S7.14                  .....................
15. Fourth effectiveness........  ...............               X   S7.15                  S5.1.1.4
16. Water recovery..............  ...............               X   S7.16                  S5.1.5
17. Spike stops.................  ...............               X   S7.17                  S5.1.6
18. Final inspection............  ...............  ...............  S7.18                  S5.6
19. Moving barrier test.........  ...............               X   S7.19                  S5.2.2.3
----------------------------------------------------------------------------------------------------------------

* * * * *
    3. Section 571.121 would be amended by revising S5.3, S5.3.6, 
S5.3.6.2 introductory text and paragraph (a), S6.1.15, and Table I to 
read as follows:


Sec. 571.121  Standard No. 121; Air brake systems.

* * * * *
    S5.3 Service brakes--road tests. The service brake system on each 
truck tractor must, under the conditions of S6, meet the requirements 
of S5.3.1, S5.3.3, S5.3.4, and S5.3.6, when tested without adjustments 
other than those specified in this standard. The service brake system 
on each bus and truck other than a truck tractor must, under the 
conditions of S6, meet the requirements

[[Page 71388]]

of S5.3.1, S5.3.3, and S5.3.4 when tested without adjustments other 
than those specified in this standard. The service brake system on each 
bus and truck other than a truck tractor manufactured on or after 
[Compliance date to be inserted] must, under the conditions of S6, meet 
the requirements of S5.3.1, S5.3.3, S5.3.4, and S5.3.6, when tested 
without adjustments other than those specified in this standard. The 
service brake system on each trailer must, under the conditions of S6, 
meet the requirements of S5.3.3, S5.3.4, and S5.3.5 when tested without 
adjustments other than those specified in this standard. However, a 
heavy hauler trailer and the truck and trailer portions of an auto 
transporter need not meet the requirements of S5.3.
* * * * *
    S5.3.6 Stability and control during braking--trucks and buses. When 
stopped four consecutive times for each combination of weight, speed, 
and road conditions specified in S5.3.6.1 and S5.3.6.2, each truck 
tractor must stop at least three times within the 12-foot lane, without 
any part of the vehicle leaving the roadway. When stopped four 
consecutive times for each combination of weight, speed, and road 
conditions specified in S5.3.6.1 and S5.3.6.2, each bus and truck other 
than a truck tractor manufactured on or after [Compliance date to be 
inserted], must stop at least three times within the 12-foot lane, 
without any part of the vehicle leaving the roadway.
* * * * *
    S5.3.6.2 Stop the vehicle, with the vehicle:
    (a) Loaded to its GVWR so that the load on each axle measured at 
the tire-ground interface is most nearly proportional to the axles' 
respective GAWRs, without exceeding the GAWR of any axle, and
    (b) * * *
* * * * *
    S6.1.15 Initial brake temperature. Unless otherwise specified, the 
initial brake temperature is not less than 150 deg.F and not more than 
200 deg.F. The temperature of each brake is measured by a single plug-
type thermocouple installed in the center of the lining surface of the 
most heavily loaded shoe or pad as shown in Figure 2. The thermocouple 
is outside any center groove.
* * * * *
TABLE I--STOPPING SEQUENCE
    1. Burnish.
    2. Stops on a peak friction coefficient surface of 0.5:
    (a) With the vehicle at gross vehicle weight rating (GVWR), stop 
the vehicle from 30 mph using the service brake, for a single-unit 
vehicle or for a truck tractor with a loaded unbraked control trailer;
    (b) With the vehicle at unloaded weight plus up to 1,500 lbs, stop 
the vehicle from 30 mph using the service brake, for a truck tractor or 
a single-unit vehicle;
    3. Manual adjustment of the service brakes allowed for truck 
tractors and single-unit vehicles within the limits recommended by the 
vehicle manufacturer.
    4. Other stops with vehicle at GVWR:
    (a) 60 mph service brake stops on a peak friction coefficient 
surface of 0.9, for a truck tractor with a loaded unbraked control 
trailer, or for a single-unit vehicle;
    (b) 60 mph emergency brake stops on a peak friction coefficient of 
0.9, for a single-unit vehicle. Truck tractors are not required to be 
tested in the loaded condition.
    5. Parking brake test with the vehicle loaded to GVWR.
    6. Manual adjustment of the service brakes allowed for truck 
tractors and single-unit vehicles, within the limits recommended by the 
vehicle manufacturer.
    7. Other stops with the vehicle at unloaded weight plus up to 1500 
lbs:
    (a) 60 mph service brake stops on a peak friction coefficient 
surface of 0.9, for a truck tractor or for a single-unit vehicle;
    (b) 60 mph emergency brake stops on a peak friction coefficient of 
0.9, for a truck tractor or for a single-unit vehicle.
    8. Parking brake test with the vehicle at unloaded weight plus up 
to 500 lbs.
    9. Final inspection of service brake system for condition of 
adjustment.
* * * * *
    Issued on December 14, 1999.
Stephen R. Kratzke,
Acting Associate Administrator for Safety Performance Standards.
[FR Doc. 99-32889 Filed 12-20-99; 8:45 am]
BILLING CODE 4910-59-P