[Federal Register Volume 65, Number 154 (Wednesday, August 9, 2000)]
[Proposed Rules]
[Pages 48660-48669]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 00-19917]


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DEPARTMENT OF TRANSPORTATION

Federal Motor Carrier Safety Administration

49 CFR Part 393

[Docket No. FMCSA-99-6266]
RIN 2126-AA46


Brake Performance Requirements for Commercial Motor Vehicles 
Inspected by Performance-Based Brake Testers

AGENCY: Federal Motor Carrier Safety Administration (FMCSA), DOT.

ACTION: Notice of proposed rulemaking (NPRM); request for comments.

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SUMMARY: The FMCSA is proposing to amend the Federal Motor Carrier 
Safety Regulations (FMCSRs) to establish pass/fail criteria for use 
with performance based brake testers (PBBTs), which measure the braking 
performance of commercial motor vehicles (CMVs). A PBBT is a device 
that can assess vehicle braking capability through quantitative measure 
of individual wheel brake forces or overall vehicle brake performance 
in a controlled test. The specific types of PBBTs addressed in this 
notice are the roller dynamometer, breakaway torque tester, and flat-
plate tester. Only those PBBTs which meet certain functional 
specifications developed by FMCSA, and published elsewhere in today's 
Federal Register, could be used to enforce the FMCSRs. The proposal 
would allow State and local enforcement officials to issue citations 
based on PBBT braking force measurements.

DATES: Comments must be received on or before October 10, 2000.

ADDRESSES: Submit written, signed comments, referencing the docket 
number that appears in the heading of this document, to the Docket 
Clerk, U.S. DOT Dockets, Room PL-401, 400 Seventh Street, SW., 
Washington, D.C. 20590-0001. All comments received will be available 
for examination at the above address from 9 a.m. to 5 p.m., e.t., 
Monday through Friday, except Federal holidays. Those persons desiring 
notification of receipt of comments must include a self-addressed, 
stamped envelope or postcard.

FOR FURTHER INFORMATION CONTACT: Mr. Gary R. Woodford, Office of Bus 
and Truck Standards and Operations, FMCSA, (202) 366-4009, or Charles 
Medalen, Office of the Chief Counsel, HCC-20, (202) 366-1354, Federal 
Highway Administration, Department of Transportation, 400 Seventh 
Street, SW., Washington, D.C. 20590. Office hours are from 7:45 a.m. to 
4:15 p.m., e.t., Monday through Friday, except Federal holidays.

SUPPLEMENTARY INFORMATION:

Table of Contents

Electronic Access
Background
Field Test Evaluations
MCSAP Funding Eligibility
PBBT Basic Principles of Operation
PBBT Functional Specifications
Round Robin Tests
Public Meeting on PBBT Pass/Fail Criteria
Discussion of Proposal
Current FMCSR Braking Requirements
Service Brake System--Proposed Out-of-Compliance Criteria
Vehicle Applicability
Braking Stability
Emergency Brake System
Parking Brake System
Test Procedures and Training
Effective Date
Rulemaking Analyses and Notices
Proposed Amendments--Part 393.52

Electronic Access

    Internet users may access all comments received by the U.S. DOT 
Dockets, Room PL-401, by using the universal resource locator (URL): 
http://dms.dot.gov. It is available 24 hours each day, 365 days each 
year. Please follow the instructions online for more information and 
help.
    An electronic copy of this document may be downloaded using a modem 
and suitable communications software from the Government Printing 
Office's Electronic Bulletin Board Service at (202) 512-1661. Internet 
users may reach the Office of the Federal Register's home page at: 
http://www.nara.gov/fedreg and the Government Printing Office's 
database at: http://www.access.gpo.gov/nara. 

[[Page 48661]]

Background

    Assessment of large truck and bus braking capability in the United 
States has traditionally been done using visual- and sensory-based 
inspection methods. These include visual examination of components, 
measurement of push-rod travel on air braked vehicles, and listening 
for air brake system leaks. Truck and bus fleets, repair and 
maintenance facilities, and the enforcement community all generally use 
this method to look for defective brakes. With regard to roadside 
inspections conducted by Federal and State officials, guidelines 
developed by the Commercial Vehicle Safety Alliance (CVSA) are used, 
under which an unsafe vehicle can be placed out of service (OOS). These 
guidelines are the North American Uniform Vehicle Out-of-Service 
Criteria, used by officials in the United States, Canada, and Mexico. 
While this method has been successful, it does have limitations. These 
include (1) falsely identifying adequately braked vehicles as unsafe 
and placing them OOS, (2) brake force-related deficiencies but no 
visually apparent defects, and (3) the inability to inspect the brake 
systems on more than a small portion of the commercial vehicle 
population due to the time involved.
    In the early 1990s, the Federal Highway Administration (FHWA) \1\ 
initiated research to evaluate various types of performance-based brake 
testing technologies for application to commercial motor vehicle 
inspections. The purpose of the research was to determine, through 
laboratory investigation, if performance-based brake testers (PBBTs) 
could be used to evaluate commercial vehicle braking capability. A PBBT 
is a device that can assess vehicle braking capability through 
quantitative measure of individual wheel brake forces or overall 
vehicle brake performance in a controlled test. The PBBTs cannot 
replace an inspector in finding brake defects unrelated to immediate 
brake performance, such as air leaks, chafed brake hose, or thin brake 
pads. However, they can provide an objective and consistent measure of 
vehicle braking performance, irrespective of brake type, energy supply, 
or actuation method, and without having to crawl underneath the vehicle 
as with the current inspection method. The PBBTs are widely used for 
brake inspection in Europe and Australia, and are beginning to emerge 
as both an enforcement tool and diagnostic aid for private sector 
maintenance and repair shops.
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    \1\ On December 9, 1999, the President signed the Motor Carrier 
Safety Improvement Act of 1999 (Public Law 106-159, 113 Stat. 1748), 
which established the FMCSA in the Department of Transportation. 
Prior to that time, the functions that are now carried out by the 
FMCSA were carried out within the FHWA.
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Field Test Evaluations

    After analyzing various PBBT technologies during the above 
referenced research, the FHWA selected several types for further 
evaluation in roadside field-test inspections. The types selected were 
the: (1) Roller dynamometer, (2) flat-plate tester, (3) breakaway 
torque tester, (4) infrared system, and (5) decelerometer. During the 
field testing, joint roadside inspections with State officials were 
conducted on almost 3,000 commercial vehicles. The joint inspections 
consisted of a CVSA Level 4 inspection \2\ and a PBBT test. Ten States 
and several commercial fleets participated in the program with each 
evaluating a specific type of PBBT. The ten States which volunteered to 
participate in the evaluation were Colorado, Connecticut, Indiana, 
Maryland, Minnesota, Nevada, Ohio, Oregon, West Virginia, and 
Wisconsin. The roller dynamometer, flat-plate, and breakaway torque 
testers were evaluated for at least one year by CVSA Certified State 
Inspectors. The infrared system and decelerometer were also 
investigated in the field, though less extensively than the three other 
types of PBBTs. The PBBTs used in this program were first- and second-
generation prototype machines to which improvements have since been 
made by their PBBT manufacturers.
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    \2\ Level 4 inspection is the CVSA designation for a Special 
Inspection, which typically includes a one time examination of a 
particular item in support of a study or to verify or refute a 
suspected trend. In this study the CVSA Level 4 inspection comprised 
the brake and tire portions of a full Level 1 inspection. Level 1 is 
the most thorough inspection, including the tires, brake system, 
driver documents, and a variety of other vehicle safety systems.
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    During the field evaluation testing, data were collected from both 
the CVSA Level 4 inspections and the PBBT measurements. The degree of 
correlation between the two methods was identified. Data on the 
operational characteristics of each PBBT were also collected and 
evaluated, including set-up and tear down times, maintenance 
requirements, calibration, operator skill level needed, user interface, 
and vehicle inspection times. These data on operational characteristics 
were gathered to help in the development of PBBT functional 
specifications, which are discussed below in more detail.
    Agreement on individual weak or defective brakes identified by the 
CVSA inspection method versus those identified by a PBBT ranged from 53 
to 88 percent, depending on the type of PBBT. This was considered 
reasonable since the two methodologies assess different brake system 
characteristics. The PBBTs used in the field tests were not necessarily 
faster than the brake-only portion of the CVSA inspection, considering 
time for data entry, driver instruction, and printing of test results. 
However, the times were generally considered comparable. It was 
apparent that 30 to 80 five-axle vehicles per eight-hour workday could 
be screened for further CVSA inspection using one of the PBBT 
technologies. Accurate screening is important since only approximately 
8-12 vehicles per eight-hour workday per inspector can be checked using 
a CVSA Level 1 inspection.\3\
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    \3\ A Level 1 inspection usually takes approximately 20 to 30 
minutes if there are no violations of applicable regulations, and 
includes both the driver and the vehicle. The inspector reviews the 
driver's license, medical certificate, record of duty status (or log 
book) and any readily available supporting documents. The inspection 
of the vehicle includes an examination of the brake system; coupling 
devices; exhaust system; frame; fuel system; cargo securement; 
steering system; suspension system; tires; trailer body; wheels, 
rims and hub assemblies; and windshield wipers.
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    The overall results of the field test evaluations indicated there 
were no insurmountable performance or operational limitations with the 
roller dynamometer, flat-plate, or breakaway torque testers that would 
prevent them from being used for screening purposes or enforcement. 
However, the infrared and decelerometer technologies did present some 
difficulties. In the case of the onboard decelerometer, which measures 
deceleration rate during a vehicle stop, finding a convenient and large 
enough space to perform a panic stop with a commercial motor vehicle 
was at times difficult. Moreover, it is likely that few commercial 
vehicle drivers would be willing to perform a panic stop in other than 
an emergency situation because of the potential damage to onboard 
cargo. Results using the decelerometer were also found to be strongly 
dependent on driver skill. In the case of the infrared system, 
applicability of this technology was found to be limited to the 
detection of inoperative brakes or brakes with push rod stroke 
measurements in excess of 12.7 mm (0.5 inch) beyond the recommended 
adjustment limit. Although the decelerometer and infrared system 
technologies will not be addressed further in this notice, the FMCSA is 
continuing its research into use of the infrared technology as a 
possible brake screening device for vehicles.

[[Page 48662]]

    A final report describing in greater detail the results of these 
field test evaluations has been placed in the docket. The report is 
titled, ``Development, Evaluation, and Application of Performance-Based 
Brake Testing Technologies,'' February 1999, Report No. FHWA-MC-98-048. 
Copies of the report may be purchased from the National Technical 
Information Service (NTIS), Springfield, Virginia 22161, telephone 
(703) 605-6000. The NTIS accession number for this publication is PB99-
134454.

MCSAP Funding Eligibility

    During the period 1996-98, the FHWA issued four policy memoranda 
advising that specific PBBTs are eligible for funding under the Motor 
Carrier Safety Assistance Program (MCSAP). Copies of the memoranda are 
available in the docket referenced above and are dated April 1, 1996, 
October 8, 1996, March 13, 1997, and November 3, 1998. The MCSAP is a 
Federal program, administered by FMCSA, providing funds to States and 
U.S. territories in support of commercial motor vehicle safety. This 
means that States or territories may use MCSAP funding to purchase one 
of the approved PBBTs for use in commercial motor vehicle brake 
inspections. To date, however, these prototype devices have only been 
used for screening or sorting purposes, and not enforcement, since PBBT 
pass/fail criteria have not yet been established within the Federal 
Motor Carrier Safety Regulations (FMCSRs). Specific pass/fail criteria 
for PBBTs are being proposed today, under Discussion of Proposal 
presented below.
    The PBBTs which have been approved to date for MCSAP funding are:

 Hunter B400T Flat Plate Tester (in-ground)
 Nepean \4\ Mark III Roller Dynamometer (portable)
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    \4\ Nepean is now called Vehicle Inspection Systems (VIS).
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 Nepean Mark IV Roller Dynamometer (portable)
 Hicklin RBD Roller Dynamometer (portable)
 Radlinski RAI 12200 Roller Dynamometer (in-ground)
 Radlinski RAI 20200 Roller Dynamometer (portable)

    The above referenced policy memoranda set forth requirements and 
suggested procedures for States to follow in using the PBBTs to help in 
gathering field evaluation data and information relative to the 
functional specifications of PBBTs. As the memoranda were issued, they 
reflected the evolving progress made in the development of functional 
specifications for PBBTs.

PBBT Basic Principles of Operation

    The most common and major feature of PBBTs--the roller dynamometer, 
flat-plate tester, and breakaway torque tester--is that each can 
measure vehicle braking force \5\ so that vehicle total brake force-to-
gross vehicle weight (BFTotal/GVW) can be determined. Gross 
vehicle weight can be measured separately and the data entered into the 
PBBT, or, on some, the PBBTs can determine GVW by summing individual 
axle loads.
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    \5\ Braking force is the force that the outer diameter of the 
tire imparts on the road surface as a result of the brakes being 
applied.
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    In the case of the roller dynamometer the vehicle is driven onto 
the device so that the wheels on the axle being tested are supported by 
a pair of powered rollers, fore and aft of the wheels. During the test, 
the rollers impose rotational motion (up to five mph) to the wheels. As 
the vehicle brakes are applied and resist the wheel rotation imposed by 
the powered rollers, the brake force imparted through the tires to the 
rollers is measured. As the driver applies the brake pedal, braking 
force increases until the friction between the rollers and tires is 
exceeded, at which point wheel lockup and tire slippage occur, and the 
test is terminated. If insufficient brake force is available to achieve 
wheel lockup, the test is terminated after a fixed period of time. The 
procedure is repeated for each axle on the vehicle.
    With the breakaway torque tester (BTT) the tires are gripped by 
opposing curved pads. Instead of the PBBT driving the wheels and then 
having the brakes applied, as with the roller dynamometer, full brake 
force is first applied. The breakaway torque tester then attempts to 
rotate the wheels through an instrumented torque arm to determine 
whether the brakes can resist this force up to a predetermined target 
value. The test is terminated when the target value is reached, or 
maximum available brake force is exceeded and the wheel begins to 
rotate. Because of the gripping action of the breakaway torque tester 
on opposing sides of the tire, maximum measured brake force is not 
limited by having simple tire contact friction only, as with the roller 
dynamometer. The procedure is repeated for each axle on the vehicle.
    For the flat-plate tester the vehicle is driven at two to ten mph 
(depending on tester) onto pairs (left and right) of in-line plates 
mounted through load cells to a fixed ``ground'' system. As the vehicle 
is driven over the plates, the brakes are applied and force 
measurements--both braking and wheel load--are obtained as the vehicle 
comes to a stop. More than one stop may be required depending upon the 
number of axles involved and the flat plate configuration.

PBBT Functional Specifications

    On December 8, 1997, the FHWA held a public meeting at the National 
Highway Traffic Safety Administration (NHTSA) Vehicle Research and Test 
Center to discuss the development of functional specifications for 
PBBTs. A notice announcing the meeting was published in the Federal 
Register on November 13, 1997 (62 FR 60817). Data gathered during the 
PBBT field evaluation tests, referenced above, served as background 
information for draft functional specifications, which were discussed 
at the meeting. In addition to the NHTSA and the FHWA, the following 
companies were represented at the meeting: Battelle, B&B Automotive, 
B&G Technologies, Inc., Dennis National Lease, Hicklin Engineering, 
Hunter Engineering Company, Gooch Brake, MGM Brakes, Motion Control 
Industries, Inc., Nepean Engineering Pty. Ltd., Radlinski & Associates, 
Inc., and Truckalyser Canada, Inc. Most of the participants were either 
manufacturers of PBBTs or distributors of such devices.
    On June 5, 1998, the FHWA published a Federal Register notice (63 
FR 30678) requesting public comments on the proposed functional 
specifications, which incorporated comments received during the public 
meeting. The agency requested further public comment through this 
notice to ensure that all interested persons who were unable to attend 
the meeting would have an opportunity to comment on this subject. The 
functional specifications are intended to be generic and, therefore, 
applicable to a range of PBBT technologies. They include requirements 
for (1) functional performance, such as measurement accuracy with 
tolerances, calibration, and operator interface, (2) physical 
characteristics including portability, (3) environmental resistance, 
(4) operator safety, (5) documentation, including operator and 
maintenance manuals, and (5) the skill level and number of operator 
personnel required. The specifications also include quality assurance 
provisions or methodologies for verifying PBBT compliance with each of 
the functional specification requirements.
    The intent is for the functional specifications to serve as a 
guideline for

[[Page 48663]]

States in determining whether a particular PBBT would be eligible for 
funding under MCSAP, and to ensure a certain level of PBBT accuracy and 
performance. The final functional specifications are published 
elsewhere in today's Federal Register.

Round Robin Tests

    In July 1998, the FHWA conducted a series of round robin tests to 
assess the suitability of PBBTs for use in enforcement. These were 
conducted at the National Highway Traffic Safety Administration's 
Vehicle Research and Test Center. The purpose of the tests was to 
evaluate the ability of current generation PBBTs to accurately and 
consistently (1) measure the brake forces and wheel loads of commercial 
motor vehicles, and (2) then predict the vehicle's deceleration 
capability from a 32.2 km/hr (20 mph) on-road stop.
    The test program involved PBBT tests and 32.2 km/hr (20 mph) stops 
using two different vehicles, which were tested fully laden and 
unladen, with weak brakes on selected wheels. The vehicles were (1) a 
two-axle flatbed straight truck, and (2) a three-axle tractor, two-axle 
flatbed semi-trailer combination. These were selected for the tests 
since they were considered representative of a majority of the 
commercial vehicle axle configurations on the road. There were eight 
PBBTs used in the testing: five roller dynamometers (two in-ground and 
three portable), two flat-plate testers, and one breakaway torque 
tester.
    Results indicated that, under most test conditions, the accuracy 
and repeatability of most of the PBBT results, regardless of the 
principle of operation, were acceptable for meeting the functional 
specifications referenced above, and therefore for use in law 
enforcement. Nearly all of the PBBTs were able to accurately measure 
the vehicle brake forces. In contrast, several of the PBBTs had 
difficulty reporting accurate vehicle weights. For the most part, 
however, this was related to test procedures. Calibration checks of the 
PBBT weighing mechanisms indicated that all of the PBBTs could meet the 
functional specifications. In those instances where PBBT accuracy did 
not achieve acceptable performance, the problems were identified and 
conveyed to the PBBT manufacturers as recommendations for improvement. 
Most of the recommendations were consistent with the requirements of 
the PBBT functional specifications.
    Copies of the report, further describing the round robin tests, are 
available in the docket referenced above. The report is titled, ``PBBT 
Round-Robin Testing,'' February 2000.

Public Meeting on PBBT Pass/Fail Criteria

    On October 2, 1998, the FHWA held a public meeting in Rochester, 
New York, to discuss recommendations for PBBT pass/fail criteria, based 
upon the field evaluation and round robin tests referenced above. The 
meeting gave interested persons an opportunity to discuss with FHWA 
representatives and researchers specific recommendations for vehicle 
braking force requirements based on PBBT measurements. A notice 
announcing the meeting was published in the Federal Register on August 
27, 1998 (63 FR 45792). In addition to FHWA representatives, and those 
from Battelle Memorial Institute which conducted the research, the 
following organizations were represented at the meeting: Abex Friction 
Products, American Trucking Associations, Carlisle Motion Control 
Industries, Inc., Gooch Brake and Equipment Co., Gunite Corporation, 
Heavy Duty Brake Manufacturers Council, Hunter Engineering Co., Meritor 
Heavy Vehicle Systems, Nevada Automotive Test Center, New York State 
Department of Transportation, Oregon State Department of 
Transportation, Radlinski & Associates, Inc., Signal Processing 
Systems, Vehicle Inspection Systems (Sydney, Australia), and Veridian 
Calspan Operations. For the most part, these consisted of PBBT and 
brake component manufacturers, vehicle testing laboratories, State 
departments of transportation, and industry associations.
    In addition to specific recommendations for PBBT pass/fail 
criteria, the meeting addressed other issues including the capabilities 
of currently available PBBTs, and whether the pass/fail criteria should 
apply to all vehicles or only those with a GVWR of 4,537 kg (10,001 
pounds) or more. All of the meeting comments and recommendations have 
been taken into consideration by the FMCSA in the development of 
today's proposal.

Discussion of Proposal

Current FMCSR Braking Requirements

    Currently, the requirements for commercial motor vehicle (CMV) 
braking performance are specified in Sec. 393.52. Section 393.52(d) 
specifies minimum braking force as a percentage of actual gross vehicle 
weight (GVW), minimum deceleration, and maximum stopping distance 
requirements for the service brakes,\6\ and maximum stopping distance 
requirements for the emergency brake system, all from a vehicle speed 
of 32.2 km/hr (20 mph). For service brake systems all three 
requirements must be met to achieve compliance with the regulation. 
Conformity to the stopping distance requirements is determined with the 
vehicle on a hard surface that is substantially level, dry, smooth, and 
free of loose material. During the stop, the vehicle must not deviate 
from a 3.7-meter (12-foot) wide lane. The requirements apply to all 
CMVs or combinations of CMVs subject to the FMCSRs under any loading 
condition. Criteria are specified for vehicles having a gross vehicle 
weight rating (GVWR) greater than 4,536 kilograms (10,000 pounds), as 
well as those with a GVWR of 4,536 kilograms (10,000 pounds) or less. 
For example, a passenger-carrying vehicle with GVWR greater than 4,536 
kilograms (10,000 pounds), and traveling at 32.2 km/hr (20 mph), must 
achieve a braking force equal to 43.5 percent of GVW, which produces 
4.3 m/sec\2\ (14 ft/sec\2\) deceleration, and a 10.7-meter (35-foot) 
maximum stopping distance. For emergency brake systems on such 
vehicles, the maximum specified stopping distance is 25.9 m (85 ft). As 
noted in an earlier Federal Register document (37 FR 5250, March 11, 
1972), the stopping distances are based on data derived from actual 
braking tests conducted in 1963.
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    \6\ Section 393.5, Definitions, specifies service brake system 
as a primary brake system used for slowing and stopping a vehicle.
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    There is a definite mathematical relationship between the braking 
forces as percentages of GVW and the corresponding decelerations 
specified in Sec. 393.52(d). Dividing the deceleration by 9.8 m/sec\2\ 
(32.2 ft/sec\2\), which is the acceleration of gravity, yields the 
corresponding braking force as a percentage of GVW. In the above 
example, dividing 4.3 m/sec\2\ (14 ft/sec\2\) by 9.8 m/sec\2\ (32.2 ft/
sec\2\) yields the 43.5 percent braking force as a percentage of GVW. 
Values for braking force as a percentage of GVW were included in the 
current regulation because there were some brake testing devices which 
utilized this measure. The Tapley decelerometer, for example, measured 
maximum deceleration during an actual vehicle stop, but was calibrated 
to read equivalent braking force as a percentage of GVW.
    As referenced earlier, there are practical difficulties in 
performing these tests at roadside inspection facilities, because of 
space limitations and the issue of CMVs with deceleration-

[[Page 48664]]

sensitive cargo. Thus, the above performance requirements are rarely 
enforced by Federal and State officials. Instead, current inspections 
involve visual, ``hands-on'' examination of brake system components to 
identify unsafe vehicles, based on the guidelines developed by the 
CVSA. While successful and productive, this method does have 
limitations, such as the number of vehicles that can be inspected on a 
given day. This factor alone is significant, given that the number of 
interstate motor carriers listed in the FMCSA Motor Carrier Management 
Information System (MCMIS) \7\ has more than doubled since 1990, and is 
expected to increase even more. The PBBTs, on the other hand, have the 
advantage of being able to measure actual vehicle braking performance 
for enforcement purposes, as well as increase CMV volume in roadside 
inspections.
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    \7\ MCMIS is a central repository of comprehensive motor carrier 
and safety data maintained by the FMCSA.
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Service Brake System--Proposed Out-of-Compliance Criteria

    In light of the above information, the FMCSA is today proposing 
alternative brake performance criteria for use with PBBTs in 
determining CMV service brake system compliance with Sec. 393.52(a)(1) 
and (a)(2). These specify CMV requirements for minimum braking force as 
a percentage of GVW and minimum deceleration from 32.2 km/hr (20 mph). 
The new PBBT criteria would not replace existing requirements, but 
would serve as an alternative whenever PBBTs are used for determining 
compliance with Sec. 393.52(a)(1) and (a)(2). Because part 393 does not 
yet provide for the use of PBBTs, this technology is currently used by 
State and local officials enforcing the FMCSRs, or compatiblie State 
laws or regulations, only for screening purposes. The proposed 
amendments would enable enforcement officials to issue citations for 
inadequate brakes based upon PBBT test results.
    The proposed criteria are based on braking force and actual GVW, 
since all PBBTs which meet these functional specifications must be 
capable of measuring braking force. Determining compliance based on 
braking force as a percentage of GVW allows use of the PBBTs. In 
developing the proposal, the FMCSA considered several options based on 
all of the research and other information referenced above. The 
specific performance criteria which the agency is proposing for use 
with PBBTs, after considering all available information, are the 
minimum requirements for braking force as a percentage of GVW already 
specified in the current regulation. These values are presented in 
table 1, along with the corresponding decelerations and stopping 
distances, specified in Sec. 393.52(d), as follows:

                      Table 1.--Service Brake System--Proposed Out-of-Compliance Criteria
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                                                                   Braking force                    Application
                                                                       as a                         and braking
                                                                   percentage of   Deceleration     distance in
                      Type of motor vehicle                        gross vehicle    in feet per      feet from
                                                                  or combination      second       initial speed
                                                                      weight                         of 20 mph
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A. Passenger-carrying vehicles:
    (1) Vehicles with a seating capacity of 10 persons or less,             65.2              21              20
     including driver, and built on a passenger car chassis.....
    (2) Vehicles with a seating capacity of more than 10                    52.8              17              25
     persons, including driver, and built on a passenger car
     chassis; vehicles built on a truck or bus chassis and
     having a manufacturer's GVWR of 10,000 pounds or less......
    (3) All other passenger-carrying vehicles...................            43.5              14              35
B. Property-carrying vehicles:
    (1) Single unit vehicles having a manufacturer's GVWR of                52.8              17              25
     10,000 pounds or less......................................
    (2) Single unit vehicles having a manufacturer's GVWR of                43.5              14              35
     more than 10,000 pounds, except truck tractors.
     Combinations of a 2-axle towing vehicle and trailer having
     a GVWR of 3,000 pounds or less. All combinations of 2 or
     less vehicles in driveaway or towaway operation............
    (3) All other property-carrying vehicles and combinations of            43.5              14              40
     property-carrying vehicles.................................
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    Section 393.52(d) currently specifies 43.4 for the braking force 
value of vehicle types listed in item B.(3) of table 1. However, in 
this notice 43.5 is shown and being proposed, since the corresponding 
deceleration of 14 ft/sec\2\ divided by the acceleration of gravity, 
32.2 ft/sec\2\, is 43.5 when rounded off.
    In addition, the current regulation at Sec. 393.52(a) requires CMVs 
to meet all three of the specified performance measures shown above. 
Under today's proposal this would not change. However, enforcement 
officials and motor carriers could use PBBTs to determine compliance 
with the minimum requirements for braking force as a percentage of GVW 
(BFTotal/GVW), \8\ specified in Sec. 393.52(a)(1); 
compliance with that requirement would also satisfy the minimum 
deceleration requirement specified in Sec. 393.52(a)(2). It would be 
redundant to require the measurement of deceleration along with braking 
force as a percentage of GVW, because of the simple mathematical 
relationship that exists between the two parameters (braking force as a 
percentage of GVW = deceleration/acceleration of gravity). As indicated 
earlier, braking force as a percentage of GVW was specified along with 
deceleration in the current regulation, because certain brake testing 
devices measured maximum deceleration during an actual vehicle stop, 
but were calibrated to read in equivalent braking force as a percentage 
of GVW. This is not the case with the PBBTs being addressed in this 
notice.
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    \8\ BFTotal represents the sum of the braking forces 
for the service brakes at each wheel of the vehicle or vehicle 
combination.
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    Therefore, those CMVs which achieve a maximum PBBT-measured braking 
force, as a percentage of GVW, that is equal to or greater than the 
braking force levels specified above in table 1 would be considered in 
compliance with both the braking force and deceleration requirements 
specified in Sec. 393.52(a)(1) and (a)(2), respectively. Those CMVs 
which do not meet the braking force levels specified in table 1 would 
be

[[Page 48665]]

considered in non-compliance with both the braking force and 
deceleration requirements, thereby enabling enforcement officials to 
issue citations.
    The FMCSA is proposing today the same requirements for PBBT-
measured braking force as a percentage of GVW that are in the current 
regulation, to assure a continuing and adequate level of CMV safety 
performance on our nation's highways. The agency has no information to 
indicate that these levels are too low for achieving this purpose, or 
that they are too high and therefore a burden for motor carriers to 
achieve. At the same time, however, the agency recognizes that the 
latest amendments to these requirements were published 28 years ago (37 
FR 5250, March 11, 1972; 37 FR 10727, May 27, 1972; and 37 FR 11336, 
June 7, 1972), and that they are rarely enforced. The FMCSA requests 
comments on whether these requirements are still appropriate in light 
of more recent vehicle brake system and testing technologies, or 
whether they should be increased or decreased and to what level. 
Persons providing comments are requested to include supporting research 
and test data or other documentation.
    The agency would retain the stopping distance requirements in 
today's proposal because it believes that a satisfactory PBBT-measured 
braking force as a percentage of GVW does not necessarily guarantee 
compliance with the corresponding stopping distance specified in 
Sec. 393.52(a)(3). The proposed braking forces as percentages of GVW 
represent the maximum braking forces achieved during actual vehicle 
stops, and the PBBT functional specifications also require PBBTs to 
measure maximum braking forces. However, this maximum braking force 
cannot be used to compute corresponding stopping distance, because 
maximum braking force may not be sustained over the entire stop. Other 
factors, such as brake system imbalance, can cause the braking force, 
and therefore deceleration, to decrease significantly after reaching a 
maximum. In addition, the distance traveled during brake application 
and brake force buildup varies with vehicle type, being negligible for 
many light vehicles and greatest for combinations of commercial 
vehicles. Thus, a vehicle with some brake system imbalance, for 
example, or slower than normal brake application time, could comply 
with the specified braking force but still not achieve the specified 
stopping distance. For these reasons the FMCSA is retaining the current 
stopping distance requirements in today's proposal. However, the agency 
requests comments from PBBT manufacturers and users. How closely from a 
safety standpoint do PBBT-measured braking forces correlate to CMV 
stopping distances during actual stops from 32.2 km/hr (20 mph)? Is the 
correlation close enough to use PBBTs to satisfy all three current 
requirements in Sec. 393.52(a), i.e., minimum braking force as a 
percentage of GVW, minimum deceleration, and maximum stopping distance? 
Please discuss. Persons providing comments are requested to include 
supporting rationale and test results or other documentation.
    As referenced above, those CMVs which do not meet the PBBT-measured 
braking forces specified in today's proposal would be considered out-
of-compliance with both the braking force and deceleration requirements 
of Sec. 393.52(a), thereby enabling State and local enforcement 
officials to issue citations relative to the service brake system.
    If today's proposal is adopted, the FMCSA intends to work with the 
CVSA, and others as appropriate, to develop a list of likely brake 
system components or causes responsible for low PBBT measurements on 
CMVs. The agency believes that this guidance would be helpful to motor 
carriers and enforcement officials in identifying and correcting the 
inadequate braking conditions. Upon correction, the motor carrier would 
then certify correction on the roadside inspection report as outlined 
above. Under this approach, the FMCSA would not require a post-
inspection PBBT measurement, as long as the involved motor carrier 
certifies correction of the deficiency consistent with existing FMCSRs. 
The agency requests comments on this approach. Should a post-inspection 
PBBT measurement be required and under what conditions?

Vehicle Applicability

    As shown in table 1 in this preamble, the FMCSA would propose that 
the above PBBT pass/fail criteria be applicable to all CMVs or CMV 
combinations subject to the FMCRs. The term CMV is defined by statute 
(49 U.S.C. 31132) to mean a self-propelled or towed vehicle used on the 
highways in interstate commerce to transport passengers or property, if 
the vehicle: (1) Has a GVWR or GVW of at least 10,001 pounds, whichever 
is greater; (2) is designed or used to transport more than 8 passengers 
(including the driver) for compensation; (3) is designed or used to 
transport more than 15 passengers, including the driver, and is not 
used to transport passengers for compensation; or (4) is used in 
transporting material found by the Secretary of Transportation to be 
hazardous under section 5103 of title 49, and transported in a quantity 
requiring placarding under regulations prescribed by the Secretary 
under section 5103. With the exception of vehicles designed or used to 
transport 9 to 15 passengers (including the driver) for compensation, 
virtually all of the CMVs covered by the statutory definition are 
currently subject to part 393 and would, therefore, be covered by this 
rulemaking. The agency does not intend to subject these smaller 
passenger vehicles to the braking requirements at this time.
    The agency believes it is appropriate to provide PBBT pass/fail 
criteria for both light CMVs (GVWR or GVW of 4,536 kg (10,000 pounds) 
or less) and heavy CMVs (GVWR or GVW greater than 4,536 kg (10,000 
pounds)). Because PBBTs have the capacity to measure braking force on 
both light and heavy vehicles, the FMCSA believes that the benefits 
associated with PBBTs should be made available to a wide range of CMVs. 
These include the benefit of increased numbers of roadside inspections, 
and the safety benefit of measuring actual vehicle braking performance. 
However, the agency requests comments on whether it is appropriate or 
necessary to provide PBBT pass/fail criteria for light CMVs, since they 
represent a relatively small proportion of all CMVs and are, therefore, 
less likely to undergo roadside brake inspections than are heavy CMVs. 
As an alternative, PBBT pass/fail criteria could be limited to those 
CMVs with GVWR or GVW greater than 4,536 kg (10,000 pounds). Persons 
submitting comments are requested to provide supporting data.

Braking Stability

    The FMCSA has tentatively decided not to propose PBBT pass/fail 
criteria for determining CMV braking stability performance at this 
time, because the agency has conducted only preliminary research in 
this area. Further research is planned.
    Current requirements for CMV braking stability during a 32.2-km/hr 
(20-mph) stop are specified in Sec. 393.52(c). The vehicle must be in 
the center of a 3.7-meter (12-foot) wide lane when the braking test 
begins and must not deviate from that lane during the test. The stop 
must be made with the vehicle on a hard surface that is substantially 
level, dry, smooth, and free of loose material.
    The FMCSA believes that PBBTs could be used to determine CMV 
braking stability by comparing PBBT

[[Page 48666]]

measured braking forces (BF/WL) \9\ from one side of the vehicle to the 
other for a given axle. Side-to-side brake force imbalance of 
sufficient magnitude can cause vehicle yaw \10\ or lane deviation while 
braking. This could result from worn brake linings or misadjusted 
brakes on one side of the vehicle. By comparing PBBT measured braking 
forces (BF/WL) on a given axle, braking stability performance could be 
assessed. When the difference between braking forces (BF/WL) on a given 
axle exceeded a certain value, vehicles could be determined to be out 
of compliance or placed out of service, depending on the criteria.
---------------------------------------------------------------------------

    \9\ BF represents braking force for one wheel, and WL represents 
vehicle load at that wheel (wheel load).
    \10\ Yaw motion is vehicle rotation about its vertical axis.
---------------------------------------------------------------------------

    There are other factors which can also contribute to vehicle lane 
deviation while braking, including low or inconsistent areas of road 
surface friction, uneven CMV load distribution, and driver skill. Apart 
from these other factors, the agency's planned research would seek to 
quantify the maximum allowable difference in braking forces (BF/WL) for 
a particular axle, necessary to stay within a 3.7-meter (12-foot) lane 
during a 32.2 km/hr (20 mph) stop. Depending on the results of this 
research, the FMCSA may propose pass/fail criteria for use with PBBTs 
in determining CMV braking stability performance. The agency requests 
comments on the feasibility of this approach. Since steering capability 
is critical during any yaw motion of the vehicle, should the PBBT pass/
fail criteria be confined to steering axles only? The agency is 
particularly interested in receiving comments from those who have 
conducted research or testing in this area. Persons submitting comments 
are requested to provide supporting documentation.

Emergency Brake System

    Section 393.5 of the FMCSRs defines emergency brake system as ``[a] 
mechanism designed to stop a vehicle after a single failure occurs in 
the service brake system of a part designed to contain compressed air 
or brake fluid or vacuum (except failure of a common valve, manifold 
brake fluid housing, or brake chamber housing).'' Thus, if there is 
leakage of the medium which actuates the brakes, i.e., air, fluid, or 
vacuum, the emergency brake system feature is designed to ensure that 
the vehicle can still be stopped, albeit in a longer distance. CMVs 
manufactured on or after July 1, 1973, must have an emergency brake 
system that conforms to the stopping distance requirements specified in 
Sec. 393.52(b). For example, a passenger-carrying vehicle with GVWR 
greater than 4,536 kilograms (10,000 pounds), and traveling at 32.2 km/
hr (20 mph), has an emergency brake system stopping distance 
requirement of 25.9 meters (85 feet). For full functioning of the 
service brakes without such failure, the stopping distance requirement 
is 10.7 meters (35 feet).
    The FMCSA has tentatively decided not to propose PBBT pass/fail 
criteria for emergency brake system performance at this time. The 
agency tentatively believes that it would not be practical to have such 
requirements for enforcement purposes at roadside inspection 
facilities. This is because a brake system leak, i.e., compressed air, 
brake fluid, or vacuum, would first have to be created to simulate a 
single failure in the service brake system. The FMCSA believes that 
this is not an appropriate or practical approach for the use of PBBTs 
during roadside inspection, because of the time involved and necessary 
modifications to an otherwise normally functioning brake system. 
However, the agency requests comments on whether it should explore ways 
to test emergency brake system performance in conjunction with PBBTs.

Parking Brake System

    Similarly, the agency has tentatively decided not to propose PBBT 
pass/fail criteria for determining CMV parking brake system \11\ 
performance at this time. The FMCSA believes that more research is 
needed before proposing specific criteria. The PBBT parking brake 
measurements which were obtained during the field evaluation tests 
referenced above could not be correlated to parking brake results from 
CVSA inspections.
---------------------------------------------------------------------------

    \11\ Section 393.5, defines parking brake system as ``A brake 
system used to hold a vehicle stationary.''
---------------------------------------------------------------------------

    Section 393.41, Parking brake system, requires that CMVs 
manufactured on and after March 7, 1990,\12\ be equipped with a parking 
brake system that can hold the vehicle or combination, under any 
loading condition, as required by Federal Motor Vehicle Safety Standard 
(FMVSS) No. 121, Air Brake Systems. FMVSS No. 121 includes requirements 
for each vehicle to meet a static drawbar pull test, or grade holding 
test, at the option of the new vehicle manufacturer. Generally, the 
drawbar pull test requires that the static retardation force, produced 
by application of the parking brake, meet minimum levels depending on 
vehicle type. For truck tractors with more than two axles, this force 
when divided by GVWR (static retardation force/GVWR), must be not less 
than 0.14. For other vehicles, this force when divided by GAWR \13\ 
(static retardation force/GAWR), must be not less than 0.28 for any 
axle (other than a steerable front axle). In the case of the grade 
holding test, the vehicle must remain stationary on a 20 percent grade 
with all parking brakes applied. For either option, the vehicles must 
meet the requirements when loaded to GVWR, and at unloaded weight plus 
226.8 kg (500 pounds).
---------------------------------------------------------------------------

    \12\ Exceptions are an agricultural commodity trailer, converter 
dolly, heavy hauler, or pulpwood trailer, which must instead carry 
chocking blocks to prevent movement when parked.
    \13\ Gross Axle Weight Rating.
---------------------------------------------------------------------------

    Although the FMCSA has tentatively decided not to propose parking 
brake system PBBT criteria at this time, the agency is considering one 
approach which it may propose in the future. This approach is tied to 
the 20 percent grade holding test discussed above. Under this approach, 
the FMCSA would require a PBBT measured braking force 
(PBFTotal/GVW) \14\ for the parking system at least equal to 
that which is necessary for the vehicle to remain stationary on a 20 
percent grade. It can be shown through analytic calculation \15\ that 
this braking force would be 0.196 (PBFTotal/GVW = 0.196). 
Therefore, using this criterion for parking brake systems, those CMVs 
which could not achieve a PBBT measured braking force 
(PBFTotal/GVW) equal to or higher than 0.196 would be found 
out of compliance with the FMCSR, or placed out of service, depending 
on the criteria. By contrast, current CVSA guidelines, ``2000 North 
American Uniform Out of Service Criteria,'' require only that the 
parking brake function properly upon actuation, and that there be no 
``non-manufactured'' holes or cracks in the spring brake housing. The 
FMCSA would like to obtain comments from interested persons on the new 
approach being considered, and on whether the agency should propose 
PBBT pass/fail criteria for determining CMV parking brake performance.
---------------------------------------------------------------------------

    \14\ PBFTotal represents the sum of the braking 
forces for the parking brakes at each wheel of the vehicle or 
vehicle combination.
    \15\ The calculations and methodology for determining this are 
contained in the docket referenced above.
---------------------------------------------------------------------------

    Additionally, the agency is interested in obtaining comments on the 
level of braking force (PBFTotal/GVW = 0.196) discussed 
above. As indicated, this level would be equivalent to the 20 percent 
grade holding requirement, which is now specified for new air braked 
vehicles in FMVSS No. 121 and CMVs by reference in Sec. 393.41, Parking 
brake system. Given the wear which vehicle

[[Page 48667]]

components and linkages experience through normal usage, should the 
same requirement that is specified for new vehicle parking brake 
systems also be specified for CMVs in use? Could CMVs in use meet this 
requirement? In contrast to the 20 percent grade, or 
PBFTotal/GVW = 0.196, discussed above, comparable 
requirements for the parking brake systems of new heavy vehicles in 
Europe \16\ are an 18 percent grade for single unit CMVs and a 12 
percent grade for CMV combinations. The FMCSA is particularly 
interested in receiving comments from users and manufacturers of CMVs. 
Persons submitting comments are requested to provide supporting 
documentation.
---------------------------------------------------------------------------

    \16\ Economic Commission for Europe, ECE Regulation No. 13, 
``Uniform Provisions Concerning the Approval of Vehicles of 
Categories M, N and O with Regard to Braking,'' October 1996.
---------------------------------------------------------------------------

Test Procedures and Training

    As part of this proposal, the FMCSA is interested in receiving 
comments which address two other areas involving PBBTs.
    The first is development of standardized test procedures for each 
type of PBBT: roller dynamometer, breakaway torque tester, and flat 
plate tester. The procedures may also vary depending on the vehicle 
configuration being tested. The FMCSA believes that a uniform set of 
test procedures is needed to help assure consistent test results for a 
given vehicle from one PBBT to another. The goal would be to minimize 
or eliminate any influence that a particular PBBT operator or procedure 
might have on the test results. The agency anticipates working with 
PBBT manufacturers in the development of these procedures, so that they 
can be used by State and local enforcement officials and help assure 
uniform PBBT test results. The FMCSA requests comments on whether there 
are entities other than PBBT manufacturers which it should work with in 
developing standardized test procedures, and what issues should be 
addressed.
    The second area involves PBBT operator training. Again, the agency 
believes this is necessary to help assure consistent and valid test 
results for enforcement purposes. The FMCSA anticipates working with 
CVSA and PBBT manufacturers in developing this training. Issues to be 
addressed include principles of PBBT operation, interpretation of test 
results, test duration, and test approach for different vehicle 
configurations. After the training is developed, the FMCSA anticipates 
that each State would take responsibility for training its enforcement 
officials through use of these training materials. The FMCSA requests 
comments on whether there are entities other than CVSA and PBBT 
manufacturers, which it should work with in developing PBBT training 
for enforcement officials. The agency is especially interested in 
receiving comments from PBBT manufacturers and users concerning the 
various training issues that need to be addressed, and from State 
enforcement officials concerning the issue of training responsibility.

Effective Date

    The FMCSA would make the proposed regulatory changes effective 30 
days after issuance of a final rule. Since the use of PBBTs would be an 
option under this proposal, and not a requirement, the agency believes 
that a longer period of time is not warranted. Further, having the 
proposed requirements become effective soon after publication of a 
final rule would permit those States which have PBBTs to begin using 
them for enforcement purposes. The FMCSA also believes that having the 
proposed requirements in place would serve as an incentive for other 
States and localities to acquire this new technology and realize its 
benefits. However, the agency requests comments on whether a longer 
time period is warranted, and if so, what it should be. Commenters are 
requested to provide supporting rationale.

Rulemaking Analyses and Notices

    All comments, received before the close of business on the comment 
closing date indicated above will be considered and will be available 
for examination in the docket room at the above address, using the 
docket number appearing at the top of this document. Comments received 
after the comment closing date will be filed in the docket and will be 
considered to the extent practicable. The agency may, however, issue a 
final rule at any time after the close of the comment period. In 
addition to late comments, the FMCSA will also continue to file, in the 
docket, relevant information as it becomes available after the comment 
period closing date, and interested persons should continue to examine 
the public docket for new material.

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

    The FMCSA has determined that this action is not a significant 
regulatory action within the meaning of Executive Order 12866 or 
significant within the meaning of Department of Transportation 
regulatory policies and procedures. This proposal, if adopted, would 
establish PBBT pass/fail criteria for use in determining the braking 
performance of CMVs. State and local enforcement officials could issue 
vehicle citations based on PBBT test results. Without these enforcement 
criteria, PBBTs would continue to be used only for screening of CMVs at 
roadside inspection facilities. PBBTs enable inspectors to screen large 
numbers of CMVs for brake performance deficiencies. States and 
localities which choose to use PBBTs for enforcement purposes would 
have to purchase the devices. This action would not mandate such 
expenditures, however, since the proposal does not eliminate the 
current ``hands-on'' method for determining compliance with the braking 
regulations. Further, the FMCSA anticipates that MCSAP funding will 
continue to be available to States for purchasing PBBTs.

Regulatory Flexibility Act

    In compliance with the Regulatory Flexibility Act (5 U.S.C. 601-
612), we have evaluated the effects of this rule on small entities. The 
proposal, if adopted, would establish PBBT pass/fail criteria for use 
in determining the braking performance of CMVs. However, the proposal 
would not impose any new requirements beyond those of the existing 
rule, 49 CFR 393.52. It would simply allow States and motor carriers to 
use PBBTs to determine compliance with certain provisions of 49 CFR 
393.52. Actual performance criteria remain the same. State and local 
enforcement officials could issue vehicle citations based on PBBT test 
results. PBBTs enable inspectors to screen large numbers of CMVs for 
brake performance deficiencies. States and localities which choose to 
use PBBTs as an optional method for enforcement of the braking 
regulations would have to purchase the devices. The FMCSA anticipates 
that MCSAP funding will continue to be available to States which desire 
to purchase PBBTs. In addition, the agency believes that States will 
realize increased safety benefits from PBBTs, through increased numbers 
of roadside inspections and measurement of actual vehicle braking 
performance. Accordingly, the FMCSA certifies that this action would 
not have a significant economic impact on a substantial number of small 
entities.

Executive Order 13132 (Federalism)

    This action has been analyzed in accordance with the principles and 
criteria contained in Executive Order

[[Page 48668]]

13132, dated August 4, 1999, and it has been determined that this 
proposed rule would not have a substantial direct effect on, or 
sufficient federalism implications for, States. The proposed rule would 
not limit the policymaking discretion of States, nor would it preempt 
any State law or regulation. States that choose to use PBBTs would have 
to buy them, but such equipment would be an eligible expense under 
MCSAP.

Executive Order 12372 (Intergovernmental Review)

    Catalog of Federal Domestic Assistance Program Number 20.217, Motor 
Carrier Safety. The regulations implementing Executive Order 12372 
regarding intergovernmental consultation on Federal programs and 
activities do not apply to this program.

Unfunded Mandates Reform Act of 1995

    This rule does not impose an unfunded Federal mandate, as defined 
by the Unfunded Mandates Reform Act of 1995 (2 U.S.C. 1532 et seq.), 
that will result in the expenditure by State, local, and tribal 
governments, in the aggregate, or by the private sector, of $100 
million or more in any one year.

Paperwork Reduction Act

    The FMCSA has determined that this proposal is exempt from the 
requirements of the Paperwork Reduction Act of 1995 [44 U.S.C. 3501 et 
seq.]. There is a certification requirement that is imposed on six PBBT 
manufacturers, as discussed in the final functional specifications 
notice published elsewhere in today's Federal Register. However, OMB 
clearance is not required because there are less than 10 public 
entities affected by this certification requirement. See 5 CFR 
1320.(3)(c). In addition, there is no new paperwork requirement on the 
part of the States, because they would only be required to complete the 
same paperwork they currently prepare, when requesting funds for the 
purchase of PBBTs from the FMCSA. Accordingly, the agency has 
determined that the certification requirement does not constitute a 
``collection of information'' covered by the PRA.

National Environmental Policy Act

    The agency has analyzed this rulemaking for the purposes of the 
National Environmental Policy Act of 1969, as amended (42 U.S.C. 4321 
et seq.) and has determined that this action would not have any effect 
on the quality of the environment.

Executive Order 12988 (Civil Justice Reform)

    This action meets applicable standards in sections 3(a) and 3(b)(2) 
of Executive Order 12988, Civil Justice Reform, to minimize litigation, 
eliminate ambiguity, and reduce burden.

Executive Order 13045 (Protection of Children)

    We have analyzed this action under Executive Order 13045, 
Protection of Children from Environmental Health Risks and Safety 
Risks. This rule is not an economically significant rule and does not 
concern an environmental risk to health or safety that may 
disproportionately affect children.

Executive Order 12630 (Taking of Private Property)

    This rule will not effect a taking of private property or otherwise 
have taking implications under Executive Order 12630, Governmental 
Actions and Interference with Constitutionally Protected Property 
Rights.

Regulation Identification Number

    A regulation identification number (RIN) is assigned to each 
regulatory action listed in the Unified Agenda of Federal Regulations. 
The Regulatory Information Service Center publishes the Unified Agenda 
in April and October of each year. The RIN contained in the heading of 
this document can be used to cross-reference this action with the 
Unified Agenda.

List of Subjects in 49 CFR Part 393

    Motor carriers, Motor vehicle equipment.

    Issued on: July 24, 2000.
Clyde J. Hart, Jr.,
Acting Deputy Administrator.
    In consideration of the foregoing, the FMCSA proposes to amend 
title 49, Code of Federal Regulations, chapter III, as follows:

PART 393--[AMENDED]

    1. Revise the authority citation for part 393 to read as follows:

    Authority: 49 U.S.C. 322, 31136, and 31502; Section 1041(b) of 
Pub. L. 102-240, 105 Stat. 1914, 1993 (1991); and 49 CFR 1.73.

    2. Amend Sec. 393.52 by revising paragraph (a)(3), by adding 
paragraph (a)(4), and by revising paragraph (d) to read as follows:


Sec. 393.52  Brake performance.

    (a) * * *
    (3) Stopping from 20 miles per hour in a distance, measured from 
the point at which movement of the service brake pedal or control 
begins, that is not greater than the distance specified in the table in 
paragraph (d) of this section; or
    (4) Developing only the braking force specified in paragraph (a)(1) 
of this section and the stopping distance specified in paragraph (a)(3) 
of this section, if braking force is measured by a performance-based 
brake tester which meets the requirements of functional specifications 
for performance-based brake testers for commercial motor vehicles, 
where braking force is the sum of the braking forces at each wheel of 
the vehicle or vehicle combination as a percentage of gross vehicle or 
combination weight.
* * * * *
    (d) Vehicle brake performance table:

----------------------------------------------------------------------------------------------------------------
                                                               Service Brake Systems                 Emergency
                                                 ------------------------------------------------ brake systems:
                                                   Braking force                    Application     application
                                                       as a        Deceleration     and braking     and braking
              Type of motor vehicle                percentage of   in feet  per     distance in     distance in
                                                   gross vehicle    second per       feet from       feet from
                                                  or combination      second       initial speed   initial speed
                                                      weight                         of 20 mph       of 20 mph
----------------------------------------------------------------------------------------------------------------
A. Passenger-carrying vehicles:
    (1) Vehicles with a seating capacity of 10              65.2              21              20              54
     persons or less, including driver, and
     built on a passenger car chassis...........
    (2) Vehicles with a seating capacity of more            52.8              17              25              66
     than 10 persons, including driver, and
     built on a passenger car chassis; vehicles
     built on a truck or bus chassis and having
     a manufacturer's GVWR of 10,000 pounds or
     less.......................................
    (3) All other passenger-carrying vehicles...            43.5              14              35              85

[[Page 48669]]

 
B. Property-carrying vehicles:
    (1) Single unit vehicles having a                       52.8              17              25              66
     manufacturer's GVWR of 10,000 pounds or
     less.......................................
    (2) Single unit vehicles having a                       43.5              14              35              85
     manufacturer's GVWR of more than 10,000
     pounds, except truck tractors. Combinations
     of a 2-axle towing vehicle and trailer
     having a GVWR of 3,000 pounds or less. All
     combinations of 2 or less vehicles in
     driveaway or towaway operation.............
    (3) All other property-carrying vehicles and            43.5              14              40             90
     combinations of property-carrying vehicles.
----------------------------------------------------------------------------------------------------------------
Note: (a) There is a definite mathematical relationship between the figures in columns 2 and 3. If the
  decelerations set forth in column 3 are divided by 32.2 feet per second per second, the figures in column 2
  will be obtained. (For example, 21 divided by 32.2 equals 65.2 percent.) Column 2 is included in the
  tabulation because certain brake testing devices utilize this factor.
(b) The decelerations specified in column 3 are an indication of the effectiveness of the basic brakes, and as
  measured in practical brake testing are the maximum decelerations attained at some time during the stop. These
  decelerations as measured in brake tests cannot be used to compute the values in column 4 because the
  deceleration is not sustained at the same rate over the entire period of the stop. The deceleration increases
  from zero to a maximum during a period of brake system application and brake-force buildup. Also, other
  factors may cause the deceleration to decrease after reaching a maximum. The added distance which results
  because maximum deceleration is not sustained is included in the figures in column 4 but is not indicated by
  the usual brake-testing devices for checking deceleration.
(c) The distances in column 4 and the decelerations in column 3 are not directly related. ``Brake-system
  application and braking distance in feet'' (column 4) is a definite measure of the overall effectiveness of
  the braking system, being the distance traveled between the point at which the driver starts to move the
  braking controls and the point at which the vehicle comes to rest. It includes distance traveled while the
  brakes are being applied and distance traveled while the brakes are retarding the vehicle.
(d) The distance traveled during the period of brake-system application and brake-force buildup varies with
  vehicle type, being negligible for many passenger cars and greatest for combinations of commercial vehicles.
  This fact accounts for the variation from 20 to 40 feet in the values in column 4 for the various classes of
  vehicles.
(e) The terms ``GVWR'' and ``GVW'' refer to the manufacturer's gross vehicle weight rating and the actual gross
  vehicle weight, respectively.

[FR Doc. 00-19917 Filed 8-8-00; 8:45 am]
BILLING CODE 4910-22-P