[Federal Register Volume 67, Number 154 (Friday, August 9, 2002)]
[Rules and Regulations]
[Pages 51770-51778]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 02-20248]


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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: Final rule.

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SUMMARY: The FMCSA amends the Federal Motor Carrier Safety Regulations 
(FMCSRs) to establish pass/fail criteria for use with performance-based 
brake testers (PBBT), which measure the braking performance of 
commercial motor vehicles. 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 rule are the roller 
dynamometer, breakaway torque tester, and flat-plate tester. Only those 
PBBTs that meet certain functional specifications, developed by FMCSA, 
can be used to enforce the FMCSRs. The final rule allows motor carriers 
and State and local enforcement officials to use PBBTs to determine 
compliance with existing brake performance requirements.

DATES: This final rule is effective on February 5, 2002.

FOR FURTHER INFORMATION CONTACT: Mr. Gary R. Woodford, (202) 366-2978, 
Office of Bus and Truck Standards and Operations, Federal Motor Carrier 
Safety Administration (MC-PSV), U.S. Department of Transportation, 400 
Seventh Street, SW., Washington, DC 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

Background
PBBT Functional Specifications and MCSAP Funding Eligibility
Current Brake Performance Requirements
Proposed PBBT Pass/Fail Criteria
Comments:
    General Support
    Appropriateness of Criteria
    Stopping Distance Requirements
    Post-Inspection PBBT Measurement
    Vehicle Applicability
    Test Procedures and Training
    Effective Date
    Braking Stability, Emergency Brake, and Parking Brake
Rulemaking Analyses and Notices
Amendments--Section 393.52

Background

    On August 9, 2000, the FMCSA published a notice of proposed 
rulemaking (NPRM) in the Federal Register (65 FR 48660), addressing 
brake performance requirements for commercial motor vehicles (CMVs) 
inspected by performance-based brake testers (PBBTs). The notice 
proposed to amend the FMCSRs by establishing pass/fail criteria for 
PBBTs, when used to measure CMV braking performance. 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 the 
notice were the roller dynamometer, breakaway torque tester, and flat-
plate tester. Only those PBBTs which meet certain functional 
specifications developed by FMCSA and discussed below could be used to 
enforce the FMCSRs. The proposal would allow motor carriers and State 
and local enforcement officials to use PBBTs to determine compliance 
with Sec. 393.52.
    The proposal represented the culmination of agency research that 
began in the early 1990s. Further information on the research, and on 
PBBT basic principles of operation, are available in the NPRM of August 
9, 2000. The research included: (1) field evaluation tests, 
``Development, Evaluation, and Application of Performance-Based Brake 
Testing Technologies,'' February 1999, Report No. FHWA-MC-98-046, and 
(2) round-robin tests, ``PBBT Round-Robin Testing,'' February 2000. 
(The term ``round-robin'' describes a series of tests in which a single 
``standard'' is used to evaluate the consistency of various test 
apparatus. In the round-robin presented in this report, the 
``standard'', a specific configuration of brake forces and wheel loads 
on a heavy-duty vehicle, was used to evaluate the candidate PBBTs and 
their operating protocols.)

PBBT Functional Specifications and MCSAP Funding Eligibility

    On August 9, 2000, the FMCSA also published in the Federal Register 
a notice of final determination (65 FR 48799) establishing functional 
specifications for PBBTs, ``Guidelines for Development of Functional 
Specifications for Performance-Based Brake Testers Used to Inspect 
Commercial Motor Vehicles.'' Data gathered during the PBBT field 
evaluation research served as background for developing the 
specifications. The specifications are 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) skill level and number of operator 
personnel required. The specifications also include quality assurance

[[Page 51771]]

provisions or methodologies for verifying PBBT compliance with each of 
the functional specifications. The methodologies include analysis, 
test, demonstration, inspection, and certified vendor data. The intent 
of the specifications is to ensure a minimum level of PBBT accuracy and 
performance.
    Under the PBBT functional specifications, a PBBT manufacturer self-
certifies its PBBT to meet the functional specifications at the time of 
manufacture, and also states which specifications, if any, its PBBT 
does not meet. PBBTs that are certified to meet the functional 
specifications are eligible for funding under the Motor Carrier Safety 
Assistance Program (MCSAP). 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 certified 
PBBTs for use in commercial motor vehicle brake inspections. As part of 
the self-certification process, the PBBT manufacturer must sign a 
declaration, under penalty of perjury, that its PBBT meets the 
functional specifications at the time of manufacture. States are 
allowed to spend MCSAP funds for a PBBT only if the manufacturer has 
signed such a declaration and presented it to the State. Further 
information on self-certification and the functional specifications are 
available in the August 9, 2000 notice of final determination.

Current Brake Performance Requirements

    Currently, the requirements for CMV braking performance are 
specified in Sec. 393.52, Brake Performance. Sections 393.52(a)(1), 
(a)(2), and (a)(3) specify service brake system requirements for 
minimum braking force (BFTotal) as a percentage of actual 
gross vehicle weight (GVW), minimum deceleration, and maximum stopping 
distance, respectively, 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. The requirements apply to all 
CMVs or CMV combinations subject to the FMCSRs, under any loading 
condition.
    However, there are practical difficulties in performing such tests 
at roadside inspection facilities, because of space limitations and 
CMVs with deceleration-sensitive cargo. Thus, Federal and State 
officials rarely enforce the current performance requirements. Instead, 
current inspections involve visual, ``hands-on'' examination of brake 
system components to identify unsafe vehicles, based on guidelines 
developed by the Commercial Vehicle Safety Alliance (CVSA). While 
successful and productive, this method does have limitations, such as 
the number of vehicles that can be inspected on a given day. PBBTs, on 
the other hand, have the advantage of being able to measure actual 
vehicle braking performance as well as the potential for increased CMV 
volume during roadside inspections.

Proposed PBBT Pass/Fail Criteria

    In the NPRM of August 9, 2000, the FMCSA proposed brake performance 
criteria for use with PBBTs in determining CMV service brake system 
compliance with Sec. 393.52(a)(1) and (a)(2). These are the 
requirements for minimum braking force as a percentage of gross vehicle 
weight (BFTotal/GVW) and minimum deceleration. The proposed 
PBBT criteria would not replace existing requirements, but would serve 
as an alternative whenever PBBTs were used for determining compliance 
with Sec. 393.52(a)(1) and (a)(2).
    The specific PBBT performance criteria proposed by the agency were 
the same requirements for minimum BFTotal/GVW and minimum 
deceleration, that are already specified in the current regulation, 
Sec. 393.52(a)(1) and (a)(2). The regulation requires CMVs to meet all 
three of the performance measures shown. This would not change under 
the proposal. However, enforcement officials and motor carriers could 
use PBBTs to determine compliance with the requirements for minimum 
braking force as a percentage of gross vehicle weight, 
BFTotal/GVW, specified in Sec. 393.52(a)(1). Compliance with 
this requirement would also satisfy the minimum deceleration 
requirement specified in Sec. 393.52(a)(2), because of the simple 
mathematical relationship that exists between the two parameters 
(BFTotal/GVW = deceleration/acceleration of gravity).
    Therefore, those CMVs which achieve a maximum PBBT-measured 
BFTotal/GVW that is equal to or greater than the required 
braking force levels, 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 that do not meet 
the braking force levels would be considered in non-compliance with 
both the braking force and deceleration requirements. The PBBT pass/
fail criteria would apply to all CMVs or CMV combinations, and the 
agency proposed that it become effective 30 days after issuance of a 
final rule.
    The agency also requested comments on: (1) The appropriateness of 
using criteria taken from the current regulation, since the latest 
amendments to those requirements were published 28 years earlier, (2) 
whether PBBT-measured BFTotal/GVW should be used to satisfy 
stopping distance requirements in addition to minimum deceleration, (3) 
whether the FMCSA should require a post-inspection PBBT measurement to 
certify correction of an earlier PBBT-measured braking deficiency, (4) 
PBBT standardized test procedures, and (5) PBBT operator training.

Comments

    FMCSA received comments to the proposal from the following 15 
different organizations: American Trucking Associations, Inc. (ATA), 
ArvinMeritor, Inc. (ArvinMeritor), Beissbarth Automotive Service 
Equipment (Beissbarth), Bendix Commercial Vehicle Systems (Bendix), 
Commercial Vehicle Safety Alliance (CVSA), Electraulic, Inc. 
(Electraulic), Heavy Duty Brake Manufacturers Council (HDBMC), Hunter 
Engineering Company (Hunter), Iowa Department of Transportation (Iowa 
DOT), Motor Coach Industries, Inc. (MCI), National Automobile Dealers 
Association (NADA), Radlinski & Associates, Inc. (Radlinski), Truck 
Manufacturers Association (TMA), TSD Holdings, Inc. (TSD), and Vipac 
Engineers and Scientists, Limited (Vipac). The commenters include: (1) 
Industry associations that represent truck dealers, truck and brake 
component manufacturers, and motor carriers, (2) State and local 
enforcement agencies; (3) brake tester manufacturers; (4) vehicle 
research and testing organizations; and (5) a motor coach manufacturer.

General Support

    The following 10 commenters expressed support for the proposal: 
ATA, ArvinMeritor, Bendix, CVSA, HDBMC, Iowa DOT, MCI, NADA, Radlinski, 
and TSD.
    ATA stated that it supports the use of PBBTs for enforcement and 
endorses the proposal. CVSA also fully supports the voluntary use of 
PBBTs for enforcement, and stated that PBBTs are a good complement to 
roadside inspection methods and out-of-service criteria in use today. 
CVSA also commended the FMCSA for its extensive research and testing, 
and leadership in this rulemaking. Both ATA and Radlinski pointed out 
the potential for PBBTs to

[[Page 51772]]

decrease the time involved in roadside brake inspections and make them 
less subjective. NADA commented on the advantages that PBBTs offer to 
State and local enforcement personnel over visual brake inspection 
methods. In supporting the proposal, ArvinMeritor stated that it 
believes FMCSA had approached the evaluation and implementation of 
PBBTs in a thorough and thoughtful manner.
    Although Bendix and HDBMC commended FMCSA for its efforts, they 
also pointed out that agency research with PBBTs did not include 
vehicles with gross axle weight ratings (GAWRs) greater than 9,072 kg 
(20,000 pounds), such as special permit vehicles and heavy haulers. 
Both commenters expressed their interest in having FMCSA gather and 
report data on such vehicles.
    In response, the FMCSA sees no need at this time to initiate 
research specifically for this purpose. The agency acknowledges that 
its PBBT research has focused on vehicles with GAWRs less than 9,072 kg 
(20,000 pounds). This is because they represent the majority of CMVs on 
the road today. The heavier vehicles, referred to by Bendix and HDBMC, 
comprise a very small portion of the CMV population. Moreover, the PBBT 
functional specifications, published in the August 9, 2000 notice of 
final determination, specify that brake testers be capable of operating 
with axles weighing up to 40,000 pounds. Therefore, the heavier 
vehicles will not be prohibited from being used on PBBTs. The FMCSA 
anticipates that as PBBT usage increases, data on such vehicles will 
become available.
    Three other commenters, TMA, Hunter, and Vipac, although supportive 
of the use of PBBTs, did not support implementation of the proposal at 
the present time.
    TMA requested the FMCSA to conduct further research and testing 
before proceeding with the proposed amendment. It stated that the FMCSA 
analysis is based on only two vehicles, used in the round-robin 
research, and that this limited sample may not accurately represent how 
well PBBT brake force measurements correlate to actual stopping 
distance, given the wide variety of CMV configurations. TMA included 
test data on 16 different CMV configurations, showing that the vehicles 
met federal motor vehicle safety standard stopping distance 
requirements from 60 mph for new vehicles. TMA stated, however, that 
four of the vehicles did not pass the proposed brake force measurement 
of 0.435 (BFTotal/GVW), when tested with a PBBT believed to 
meet the FMCSA functional specifications. Thus, TMA believes it would 
be detrimental to rush implementation of PBBT pass/fail criteria that 
may conflict with new vehicle brake performance requirements, or 
without understanding how this relates to in-service braking 
requirements.
    In response to TMA, the FMCSA does not believe that further 
research is needed at the present time. Although the round-robin 
research did involve only two vehicles, the vehicles were considered 
representative of a majority of the CMV axle configurations on the 
road: (1) A two-axle flatbed straight truck and a (2) three-axle 
tractor, two-axle flatbed semi-trailer combination. In addition, a lack 
of correlation between vehicle stopping distance and maximum braking 
force, among the four vehicles that TMA refers to in its comment, does 
not necessarily mean there is a conflict between new vehicle and in-
service requirements. As the agency pointed out in its proposal, these 
two parameters may not correlate, because maximum braking force is not 
sustained over an entire stop. In addition, there are other factors 
that can influence the relationship between stopping distance and 
braking force. A more direct comparison is that of maximum PBBT-
measured braking force and maximum-measured braking force during an 
actual vehicle stop, which is what the FMCSA did in its round-robin 
research. Moreover, the agency has never claimed or intended that PBBT 
test results be used as a surrogate for determining compliance with 60 
mph stopping distance requirements for new vehicles. The FMCSA is not 
aware of any data to correlate the results of low-speed brake 
performance tests and high-speed tests, such as those conducted by TMA. 
The agency finds that its research supports the use of PBBTs to assess 
the brake performance of CMVs, and that TMA's arguments do not warrant 
a delay in the issuance of this final rule.
    Hunter, which manufactures flat-plate testers, asked that the FMCSA 
consider a different approach than the one proposed. It desires an 
approach that is not deceleration-based, and that takes better 
advantage of the individual capabilities of each brake tester type. 
Hunter stated that since the proposed pass/fail criteria are based on 
total vehicle brake force (BFTotal/GVW), it does not account 
for braking capability at individual wheels. In other words, a strong 
brake on one wheel could make up for a weak brake on another wheel, 
when summing total brake forces. According to Hunter, this would 
overlook brake force imbalances that can cause vehicle instability 
while braking. Hunter asserts that side-to-side brake balance 
measurements are the most reliable method of determining brake 
performance. Using brake balance as the criterion, would allow vehicles 
to stop on Hunter's flat-plate tester at a lower deceleration, such as 
0.3g, rather than 0.435g, for example, contained in the FMCSA proposal. 
According to Hunter, this higher deceleration stop proposed in the NPRM 
is difficult to achieve in some cases, and leads to cargo shifting.
    The FMCSA does not concur with Hunter's rationale. While brake 
balance is an important consideration in assessing overall brake 
performance, it does not necessarily indicate stopping distance 
capability. For example, stopping a vehicle with weak, well-balanced 
brakes at a deceleration of 0.3g does not necessarily mean that it will 
stop at the higher 0.435g deceleration proposed in the NPRM and 
required in the current regulation. The FMCSA believes that maximum 
braking force is a better surrogate than brake balance for assessing 
stopping distance capability of heavy vehicles during roadside 
inspection. Moreover, the agency's proposal required measurement of 
maximum brake force at each wheel, which in turn provides information 
on brake force imbalance for a given axle. Finally, as discussed in 
more detail later in the preamble, no other commenter indicated that 
the proposed brake force of 0.435, BFTotal/GVW, is too high 
for motor carriers to achieve.
    Vipac only addressed the FMCSA round robin research referenced in 
the August 9, 2000 NPRM. Vipac commended the agency for its depth of 
research but recommended further work before implementing PBBT 
regulations. For the most part, the work that Vipac referred to 
involves roller dynamometer issues, including: (1) Over-predicting of 
brake force, (2) the need for improved algorithms by PBBT manufacturers 
(i.e., the PBBT internal data processing methodology by which measured 
brake force is determined), (3) the effects of low roller speed on 
accuracy, and (4) vehicle-to-PBBT geometry during testing.
    However, the FMCSA has already identified these four areas in its 
analysis of the round-robin research, and through additional research 
the agency has been working with PBBT manufacturers to resolve those 
issues. This work should be completed in 2002, and based on preliminary 
results, the FMCSA does not believe that a delay in moving forward with 
this rulemaking is warranted.
    In its comments, Vipac also advocated as an alternative, a new 
technology, the

[[Page 51773]]

on-board decelerometer, which measures deceleration rate during a 
vehicle stop. Vipac stated that this technology is less costly and more 
accurate than the PBBTs addressed in this rulemaking. As the FMCSA 
pointed out in its NPRM, a space convenient and large enough to perform 
a panic stop with a CMV can be difficult to find at roadside inspection 
facilities. Moreover, the technology referred to by Vipac is outside 
the scope of this rulemaking.
    The two remaining commenters, Beissbarth and Electraulic, did not 
specifically address the proposal. Beissbarth stated that based on its 
experience, flat-plate and breakaway torque testers do not provide 
accurate results over time. However, Beissbarth provided no information 
to support this claim. Electraulic expressed interest in the PBBT 
program, but provided no other comments in response to the proposal.
    Therefore, based on the strong support from a majority of 
commenters, the FMCSA is today establishing pass/fail criteria for use 
with PBBTs in determining CMV service brake system compliance with 
Sec. 393.52(a)(1) and (a)(2).

Appropriateness of Criteria

    In the NPRM of August 9, 2000, the FMCSA asked for comments on 
whether the proposed PBBT pass/fail criteria are still appropriate in 
light of more recent brake system and brake testing technologies. The 
agency pointed out that the proposed criteria for BFTotal/
GVW are the same as those in the current regulation, which has not been 
amended since 1972.
    Five commenters addressed this issue. They are ATA, CVSA, HDBMC, 
Hunter, and Radlinski. All of the commenters expressed support for the 
proposed level of PBBT pass/fail criteria, with the exception of Hunter 
as already discussed. Both ATA and CVSA stated that using the same 
pass/fail criteria that are currently in Sec. 393.52 is appropriate, 
since those requirements were used in developing the current CVSA North 
American Uniform Out-of-Service Criteria. State and local enforcement 
personnel use these criteria today to determine whether a vehicle 
should be placed out-of-service for inadequate service brakes. ATA and 
CVSA also pointed out, however, that the agency should make it clear 
that the PBBT pass/fail criteria are minimums. The FMCSA agrees. CMVs 
which meet or exceed the PBBT pass/fail criteria would be considered in 
compliance with the brake force and deceleration requirements of 
Sec. 393.52(a)(1) and (a)(2).
    Radlinski stated that the PBBT pass/fail criteria are appropriate 
for vehicles with good brakes. In support of its claim Radlinski 
provided data on 81 different vehicles that it had tested using a 
Radlinski PBBT. All of the vehicles were proving ground-tested for 
stopping capability, inspected, and found to have defect-free brakes. 
The PBBT test data show that all of the vehicles passed the criterion 
(BFTotal/GVW = 0.435) by a significant margin. However, 
Radlinski also pointed out that a vehicle with adequate brakes might 
fail the test, if the coefficient of friction (COF) between the test 
surface and tire falls substantially below 0.6. This could occur when 
the tire is wet and may not have enough friction to develop the 
required brake force. The COF of 0.6 between the PBBT test surface and 
tire is the minimum under dry conditions specified in the FMCSA final 
PBBT functional specifications of August 9, 2000. Radlinski stated that 
the FMCSA should consider establishing an absolute lower COF in order 
for a test to be considered valid, and suggested 0.55. Although COF is 
outside the scope of this rulemaking, the FMCSA appreciates Radlinski's 
comments, and will consider this issue for further action.
    As discussed earlier, Hunter advocates a BFTotal/GVW 
that is lower than 0.435, such as 0.3. However, for the reasons already 
given above, the FMCSA believes Hunter has not provided sufficient 
rationale to assure adequate safety using lower PBBT pass/fail 
criteria.
    Based on these comments, the FMCSA has adopted the PBBT pass/fail 
criteria in today's final rule.

Stopping Distance Requirements

    In its proposal of August 9, 2000, the FMCSA proposed retaining the 
stopping distance requirement from 32.2 km/hr (20 mph) specified in 
Sec. 393.52(a)(3), because it believed that a satisfactory PBBT-
measured braking force would not necessarily ensure compliance with the 
stopping distance requirement. The agency pointed out that PBBT-
measured maximum braking force can not be used to compute corresponding 
stopping distance because maximum braking force is typically not 
sustained over the entire stop. 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. However, the FMCSA asked for 
comments on whether the correlation between PBBT-measured braking 
forces and stopping distance requirements is close enough to use PBBTs 
to safely satisfy all three requirements, which are in 
Sec. 393.52(a)(1), (a)(2), and (a)(3)--minimum BFTotal/GVW, 
minimum deceleration, and maximum stopping distance, respectively.
    The following four commenters responded to this issue: Radlinski, 
ATA, ArvinMeritor, and Hunter. Radlinski stated that it is impossible 
to precisely relate maximum braking force to stopping distance without 
knowing brake application time. Similarly, ATA cited the impossibility 
of accurately relating stopping distance and braking force, because of 
brake application time and other variables. ArvinMeritor stated that 
PBBTs should only be implemented to evaluate braking force, and not 
stopping distance, until the trucking industry and enforcement 
authorities have gained more experience with their use. ArvinMeritor 
did not address any of the technical issues governing the relationship 
between stopping distance and maximum braking force. Hunter stated that 
stopping distance can be calculated as accurately as deceleration when 
brake force, friction, and weight are known, assuming balanced brakes 
and constant brake force. However, as referenced above, brake force may 
not be constant during a CMV stop. Moreover, it cannot be assumed that 
the vehicle brakes are balanced, due to variations in the condition of 
the brakes and road friction. Therefore, Hunter's assertion is not 
correct. In light of these comments, the FMCSA has decided to adopt the 
stopping distance requirements as set out in the NPRM.

Post-Inspection PBBT Measurement

    Under the August 9, 2000 proposal, those CMVs which do not meet the 
specified PBBT-measured braking forces would be considered out of 
compliance with both the braking force and deceleration requirements of 
Sec. 393.52(a)(1) and (a)(2). After fixing the problem, the motor 
carrier would certify the correction on the roadside inspection report 
and return it to the issuing agency, as outlined in Sec. 396.9, 
Inspection of Motor Vehicles in Operation. This would be the same way 
that violations found under current inspection methods are handled. 
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 Sec. 396.9. However, the agency 
requested comments on whether a post-inspection PBBT measurement should 
be required and under what conditions.
    The five commenters that addressed this issue, NADA, ATA, 
ArvinMeritor, Radlinski, and CVSA, did not believe

[[Page 51774]]

the agency should require a post-inspection PBBT measurement. NADA 
suggested that it should be optional, while ArvinMeritor stated that 
such a requirement would not be an effective use of PBBT resources. 
Both ATA and ArvinMeritor supported the FMCSA proposal, stating that 
this approach is consistent with current roadside inspection follow up 
requirements in Sec. 396.9. Radlinski, however, stated that provision 
should be made to allow other methods for checking a repaired vehicle, 
such as inspection by a certified brake inspector. However, Radlinski 
provided no rationale to justify such a requirement. The agency notes 
that motor carriers are free to use whatever means they choose to 
verify post-inspection repairs on their vehicles. CVSA stated that 
generally, its member jurisdictions do not require post-inspections to 
determine whether defects have been corrected. It has established an 
international goal of verifying the repairs on 15 percent of out-of-
service violations, and referred the FMCSA to its Operations Manual for 
guidance on this subject. However, the FMCSA proposal for not requiring 
a post-inspection PBBT measurement is in the context of an out-of-
compliance violation, not an out-of-service violation. In light of 
these comments, the agency continues to believe that there should be no 
requirement for a post-inspection PBBT measurement, and today's final 
rule contains no such requirement.
    In the NPRM of August 9, 2000, the FMCSA also indicated that if the 
proposal were adopted, it intends to work with its partners and 
customers to develop a list of likely brake system components or causes 
responsible for low PBBT measurements. The agency believes that such 
guidance would be helpful to motor carriers and enforcement officials 
in identifying and correcting inadequate braking conditions.
    ATA, CVSA, and NADA expressed support for this initiative. ATA 
indicated that such a diagnostic tool is necessary to facilitate timely 
repairs, and offered to serve on a developmental task force. It also 
indicated that brake manufacturers should be involved because of new 
braking technologies. CVSA recommended that FMCSA consider providing 
federal funds to jurisdictions interested in purchasing PBBTs for 
developing guidance in identifying the inadequate braking conditions. 
NADA stated that PBBT manufacturers should be required to develop and 
make available diagnostic and repair strategies for CMVs that fail PBBT 
tests.
    The FMCSA notes that it has no authority to require PBBT 
manufacturers or others to provide the diagnostic information necessary 
to assist commercial motor vehicle operators in identifying and 
correcting braking deficiencies that result in low PBBT measurements. 
However, the FMCSA plans to seek the voluntary involvement of a cross-
section of its partners and customers to help in developing this 
information. Through ongoing research, the agency has identified issues 
that will need to be addressed. The agency anticipates that this 
preliminary work can serve as the basis for the remaining effort.

Vehicle Applicability

    In its August 2000 notice, the FMCSA proposed that PBBT pass/fail 
criteria be applicable to all CMVs and CMV combinations, consistent 
with current brake performance requirements in Sec. 393.52. The agency 
believed that because PBBTs have the capability to measure brake force 
on both light and heavy vehicles, their benefits should be made 
available to a wide range of CMVs. However, the agency requested 
comments on whether it is appropriate to provide such criteria for 
light CMVs (GVWR or GVW of 4,536 kg (10,000 pounds) or less), since 
they represent a relatively small portion of all CMVs, and are 
therefore, less likely to undergo roadside brake inspections than are 
heavy CMVs (GVWR or GVW greater than 4,536 kg (10,000 pounds)).
    However, in a separate rulemaking published on January 11, 2001, 
the agency proposed making the safety regulations applicable to CMVs 
designed or used to transport between 9 and 15 passengers. These CMVs 
would typically be less than 10,000 pounds. Therefore, if the agency 
were to adopt PBBT rules applicable to vehicles less than 10,000 
pounds, those requirements would cover small passenger-carrying 
vehicles, and light vehicles used to transport hazardous materials in a 
quantity requiring placards. As an alternative, the FMCSA stated that 
PBBT pass/fail criteria could be limited to heavy CMVs. Persons 
submitting comments were requested to provide supporting data.
    The following six commenters provided limited information: Hunter, 
ATA, CVSA, ArvinMeritor, Radlinski, and HDBMC. Hunter, ATA, and CVSA 
support the proposal to provide PBBT pass/fail criteria for all CMVs. 
Hunter stated that there is no reason not to include the light vehicles 
in providing PBBT pass/fail criteria. ATA stated that PBBTs provide a 
better opportunity to inspect the brakes on light vehicles, since they 
are more enclosed and less accessible for visual inspection than the 
brakes on heavy CMVs. However, both ATA and CVSA believe that the 
States should have the option of using PBBTs on light vehicles, but not 
be required to do so. This is consistent with the agency's proposal, 
since the use of PBBTs would be an alternative method of determining 
compliance with the brake performance requirements of Sec. 393.52. 
ArvinMeritor also supports the use of PBBTs on light vehicles, but 
recommended that FMCSA research the appropriateness of the pass/fail 
criteria. Likewise, Radlinski stated that further data is needed on the 
appropriateness of the criteria for light vehicles, and for that reason 
it does not support PBBT use on light vehicles at this time. HDBMC 
simply stated that it has no data on light vehicles. None of the six 
commenters provided any supporting data.
    After further consideration, the FMCSA has decided not to include 
PBBT pass/fail criteria for light vehicles at the present time. In 
making this decision, the agency notes that ArvinMeritor and Radlinski 
provided no rationale for questioning the appropriateness of the pass/
fail criteria for light vehicles. Nevertheless, the FMCSA recognizes 
that the CMV industry has minimal experience with the use of PBBTs on 
light vehicles. In addition, the agency's PBBT research did not include 
light vehicles. By providing pass/fail criteria for heavy vehicles 
only, today's final rule makes PBBT use possible on the vast majority 
of CMVs that undergo roadside inspection. Applying this final rule only 
to heavy vehicles will also provide the agency with an opportunity to 
further investigate the use of PBBTs on light vehicles. Therefore, 
today's final rule is applicable to those CMVs and CMV combinations 
that have a GVWR or GVW greater than 4,536 kg (10,000 pounds).

Test Procedures and Training

    In its proposal of August 9, 2000, the FMCSA indicated that if the 
proposal were adopted, it anticipated working with partners and 
customers to develop PBBT standard test procedures and operator 
training. The agency believes these are necessary to minimize or 
eliminate any influence that a particular PBBT operator, vehicle 
configuration, or PBBT type might otherwise have on test results. State 
and local officials would use the test procedures and operator training 
to help ensure uniform PBBT test results across the enforcement 
community. For both the test procedures and training the FMCSA

[[Page 51775]]

requested comments on what specific issues need to be addressed, and 
with which partners and customers the agency should work. The FMCSA 
also requested comments on whether each State should take 
responsibility for training its enforcement officials on proper PBBT 
operation, after the training material is developed.
    Eight commenters responded. They are ArvinMeritor, ATA, Bendix, 
CVSA, HDBMC, MCI, NADA, and Radlinski, all of which concurred with the 
need for standard PBBT test procedures, operator training, or both. 
Test procedure and training issues that commenters cited include brake 
lining temperature, wet weather limitations, vehicle weighing 
procedures, marginal brakes, interpretation of test results, bad test 
and allowance for retest, driver rights, test duration, test report 
format, and PBBT calibration and maintenance. ATA and Radlinski 
commented that a vehicle found to have an out-of-compliance PBBT 
measurement should be allowed the opportunity for a retest at the time 
of the inspection. ATA pointed out that this is similar to current 
procedures where a motor carrier can also inspect its vehicle at the 
time a violation is found. ArvinMeritor cited the need for 
precautionary warnings and procedures (1) to assure the safety of test 
personnel and vehicle operators, and (2) to minimize risk of damage to 
inter-axle differential (IAD) components on the test vehicle. The IAD, 
which may be locked or unlocked by the driver, serves to compensate for 
small differences in tire rolling radii between the fore and aft 
driving axles of a tandem axle. ArvinMeritor also stated that automatic 
traction control devices (ATC), which are incorporated as a feature of 
antilock brake systems, must be disabled when a single axle of a tandem 
axle vehicle is tested on a roller dynamometer PBBT. The function of 
the ATC is to provide traction when it senses that one wheel is 
slipping or spinning. If the ATC is not disabled, the vehicle will tend 
to drive off the rollers and thereby pose a safety hazard during the 
test. Likewise, the IAD on a tandem axle must be unlocked before 
testing to avoid (1) having the vehicle drive off the PBBT rollers, or 
(2) damage to IAD components. Other factors that may contribute to IAD 
damage are test duration, PBBT roller speed, and whether tandem axles 
are tested simultaneously or individually. Collectively, the commenters 
recommended that the FMCSA work with CVSA, ATA and its Technology 
Maintenance Council, HDBMC, PBBT manufacturers, brake manufacturers, 
and motor carriers to address these issues. Only one commenter, MCI, 
addressed the issue of which entity should take responsibility for PBBT 
operator training. MCI stated that the FMCSA should ensure through 
rulemaking that each state takes responsibility for training its 
enforcement officials on proper PBBT operation for the various vehicle 
configurations.
    The FMCSA appreciates these comments. As with the vehicle repair 
information, the agency plans to engage a cross-section of its partners 
and customers to help develop PBBT standard test procedures and 
operator training. Through ongoing research the FMCSA has identified 
issues that will need to be addressed. The agency anticipates that this 
preliminary work can serve as a starting point for the remaining 
effort. With regard to the MCI comment on training, the FMCSA has no 
authority to require states to take responsibility for PBBT operator 
training. However, the agency anticipates that as the training 
materials are developed, an appropriate level of federal and state 
responsibility will be reached.

Effective Date

    In the NPRM of August 9, 2000, the FMCSA proposed that use of PBBTs 
for enforcement become effective 30 days after issuance of a final 
rule. The agency stated that a longer time period would not be 
necessary, since PBBT use would be optional. Having the pass/fail 
criteria become effective soon after issuance of a final rule would 
permit States that have PBBTs to begin using them to inspect CMVs, and 
provide incentive for other States and localities to acquire the new 
technology and realize its benefits. However, the agency requested 
comments on whether a longer time period is warranted, and if so, what 
it should be.
    The following six commenters provided information on the proposed 
effective date: ATA, ArvinMeritor, CVSA, MCI, NADA, and Radlinski. 
Radlinski supports the 30-day requirement, since the use of PBBTs for 
enforcement is not mandatory. ATA also supports the 30-day time period, 
but with the caveat that those jurisdictions first using PBBTs have 
time to establish standard test procedures and operator training. 
ArvinMeritor recommended a 90-day time period to provide industry time 
to respond to the issues raised by commenters. However, ArvinMeritor 
added that the effective date should also reflect adequate time for the 
FMCSA to finalize or resolve PBBT standard test procedures, operator 
training, and other issues necessary for successful implementation. 
CVSA, MCI, and NADA did not recommend a specific time period, but did 
stress the importance of adequately addressing such issues prior to 
PBBT implementation. CVSA stated that, in light of the new PBBT pass/
fail criteria, time is also needed to modify the CVSA North American 
Uniform Out-of-Service Criteria, and software used by field inspection 
personnel.
    After considering this information, the FMCSA has decided to make 
the PBBT pass/fail criteria effective 180 days after publication of 
this final rule. Although use of PBBTs for enforcement is optional, the 
agency notes that five of the six commenters emphasized the need for 
having in place standard test procedures, operator training, and 
vehicle repair guidelines prior to PBBT implementation. The FMCSA 
agrees that these issues must be adequately addressed to ensure 
confidence in PBBT test results among those States and localities using 
them. Lack of confidence would detrimentally affect PBBT 
implementation. Only two commenters cited specific timeframes, 30 and 
90 days. The agency believes that neither of these would be adequate in 
light of the full range of issues raised by commenters, including those 
by ArvinMeritor on ATC and IAD. The FMCSA plans to engage a cross-
section of its partners and customers to help develop the necessary 
PBBT test procedures, operator training, and vehicle repair guidelines. 
The agency believes that partner and customer participation, coupled 
with the agency's preliminary research, will allow the issues to be 
adequately addressed within 180 days of issuance of the final rule.

Braking Stability, Emergency Brake, and Parking Brake

    In the NPRM of August 9, 2000, the FMCSA did not propose PBBT pass/
fail criteria for determining CMV braking stability, emergency brake, 
or parking brake performance. However, the agency did request comments 
in each of these areas.
    Braking stability performance, specified in Sec. 393.52(c), 
requires the vehicle to remain within a 3.7 meter (12 foot) wide lane 
during a 32.2 km/hr (20 mph) stop. The FMCSA stated in the NPRM that 
PBBTs could be used to determine braking stability by comparing PBBT-
measured braking forces from one side of the vehicle to the other for a 
given axle. When the difference between those braking forces exceeds a 
certain value, vehicles would be deemed out of compliance. The

[[Page 51776]]

agency stated that it might propose such PBBT pass/fail criteria in the 
future, but requested comments on the feasibility of such an approach. 
It also asked whether the criteria should be confined to steering axles 
only, since steering capability is critical to controlling the yaw 
motion of a vehicle. Yaw motion is vehicle rotation about its vertical 
axis.
    The six commenters that responded do not support PBBT pass/fail 
criteria for determining CMV braking stability. They are ATA, 
ArvinMeritor, CVSA, HDBMC, Radlinski, and TMA. ATA stated that based on 
a 1986 National Highway Traffic Safety Administration (NHTSA) study, 
(``A Demonstration of the Safety Benefits of Front Brakes on Heavy 
Trucks,'' December 1986, DOT HS 807 061) brake force imbalance across a 
heavy truck steer axle must be relatively high to impede steering 
capability. Further, all new trucks have power steering, according to 
ATA, and this helps drivers manage any steering pull due to side-to-
side brake imbalance. For other axles, ATA, ArvinMeritor, and HDBMC 
cited the requirement for antilock brake systems (ABS) on CMVs, which 
mitigate any control loss due to brake imbalance. ArvinMeritor added 
that the number of non-ABS equipped vehicles would diminish over time 
through attrition. In addition, ArvinMeritor and HDBMC stated that 
side-to-side brake forces measured at the inherently slow PBBT test 
speeds may not indicate true performance at higher vehicle speeds, 
although neither commenter provided supporting data. ATA, CVSA, 
Radlinski, and TMA support further research. CVSA cited the lack of 
information on how much side-to-side brake imbalance should be allowed. 
Radlinski stated that further research is needed to support the safety 
need for such a requirement.
    The FMCSA agrees with commenters on the need for further research 
on how much side-to-side brake force imbalance should be allowed, as 
well as PBBT capabilities. Safety need must also be assessed in light 
of the requirement for ABS on new vehicles. The agency is currently 
conducting research in this area, and will assess whether to move 
forward with such a proposal once this work is completed.
    In the case of emergency brake system performance, requirements are 
specified in Sec. 393.52(b). If there is leakage of the medium that 
actuates the brakes, i.e., air, fluid, or vacuum, the emergency brake 
system must still be able to stop the vehicle within a specified 
distance. In not proposing PBBT pass/fail criteria for the emergency 
brake system, the FMCSA stated that it would not be practical for 
enforcement at roadside inspection facilities. This is because an air, 
fluid, or vacuum leak would have to be created to simulate a single 
failure in the service brake system. The agency believed that this 
approach would not be appropriate or practical in light of the time 
involved and necessary modifications to an otherwise normally 
functioning brake system. However, the FMCSA requested comments on 
whether it should explore ways to test the emergency brake system in 
conjunction with PBBTs.
    The seven commenters that responded, ATA, ArvinMeritor, CVSA, 
HDBMC, Bendix, Radlinski, and TMA, all concurred with the agency's 
rationale and decision to not propose PBBT pass/fail criteria for the 
emergency brake system.
    In the case of parking brakes, the requirements are specified in 
Sec. 393.41 of the FMCSRs. It specifies that most CMVs, manufactured on 
or after March 7, 1990, must be equipped with a parking brake system 
that can hold the vehicle or vehicle combination under any loading 
condition, as required by Federal Motor Vehicle Safety Standard (FMVSS) 
No. 121, Air Brake Systems. FMVSS No. 121 requires each new vehicle to 
meet a static drawbar pull test, or grade-holding test, at the option 
of the vehicle manufacturer. In the case of the grade holding test, the 
vehicle must remain stationary on a 20 percent grade with all parking 
brakes applied. Although the FMCSA did not propose PBBT criteria for 
parking brakes, it stated that it was considering one approach that it 
may propose in the future. That approach would require a PBBT measured 
braking force for the parking brake system to be at least equal to that 
which is necessary for the vehicle to remain stationary on a 20 percent 
grade. The agency asked whether it should propose such criteria for the 
parking brake system, and whether it would be appropriate to require a 
parking brake force equivalent to that required of a new vehicle.
    The seven commenters that responded, ATA, ArvinMeritor, CVSA, 
HDBMC, Bendix, Radlinski, and TMA, do not support PBBT requirements for 
the parking brake system. ATA indicated that using PBBTs to test CMV 
parking brakes would not be an efficient use of time at roadside 
inspection facilities. It stated that unlike the service brake system, 
the parking brake does not present an imminent hazard. ATA and CVSA 
both indicated that focusing PBBT resources on service brakes would be 
a better use of time. HDBMC, Bendix, and Radlinski questioned the 
stringency of such a requirement. HDBMC stated that the grade-holding 
requirement of 20 percent for new vehicles was not intended as an in-
use requirement. It commented that most vehicles are parked on grades 
of six percent or less. Radlinski recommended a 12 percent grade-
holding requirement rather than 20 percent. It stated that used 
vehicles should be allowed some drop in performance. ArvinMeritor, 
Bendix, and TMA indicated that the agency should collect more research 
data on this issue before proceeding.
    FMCSA agrees that research would be needed before it proceeds with 
any proposal for parking brake PBBT pass/fail criteria. If the agency 
were to look further at tying any required parking brake force to 
grade-holding capability, it would first have to decide whether the 20 
percent requirement for new vehicles is appropriate, given the wear 
that CMV components and linkages experience through normal usage. The 
safety need for such a requirement would also have to be explored. The 
FMCSA has concluded that for the near future it is more appropriate to 
focus PBBT resources on CMV service brakes. After increased deployment 
of this new technology, the agency can further explore other potential 
applications.

Rulemaking Analyses and Notices

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 rule establishes PBBT pass/
fail criteria for use in determining the braking performance of CMVs. 
The rule does not require motor carriers to purchase PBBTs, or to use 
the technology. The rule allows the use of the technology to improve 
the ability of motor carriers and enforcement personnel to assess the 
braking capability of CMVs. State and local enforcement officials can 
now 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. States and 
localities that choose to use PBBTs for enforcement purposes will have 
to purchase the devices. This action does not mandate such 
expenditures, however, since this final rule is an optional method for 
determining compliance with the braking regulations. Further, the FMCSA 
anticipates that MCSAP funding will continue to be available to States 
for

[[Page 51777]]

purchasing PBBTs. Since this final rule does not require the purchase 
or use of PBBTs, or establish new brake performance standards that 
would necessitate changes in CMV design or maintenance, FMCSA has 
determined that it is not necessary to prepare a cost-benefit analysis.

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 
final rule establishes PBBT pass/fail criteria for use in determining 
the braking performance of CMVs. However, it does not impose any new 
requirements beyond those of the existing rule, 49 CFR 393.52. It 
simply allows States and motor carriers to use PBBTs to determine 
compliance with certain provisions of 49 CFR 393.52. Actual performance 
criteria remain the same. Motor carriers are not required to purchase 
or use PBBTs. Accordingly, the FMCSA certifies that this action does 
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 13132, dated August 4, 1999, and 
it has been determined that this final rule does not have a substantial 
direct effect on, or sufficient federalism implications for, States. 
The rule does not limit the policymaking discretion of States, nor does 
it preempt any State law or regulation. States that choose to use PBBTs 
will 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.), 
which 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 final rule 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 in the Federal Register on August 9, 2000 (65 FR 
48799). 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 are only 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 Paperwork Reduction Act.

National Environmental Policy Act

    The Federal Motor Carrier Safety Administration (FMCSA) is a new 
administration within the Department of Transportation (DOT). We are 
striving to meet all of the statutory and executive branch requirements 
on rulemaking. The FMCSA is currently developing an agency order that 
will comply with all statutory and regulatory policies under the 
National Environmental Policy Act of 1969 (42 U.S.C. 4321 et seq.). We 
expect the draft FMCSA Order to appear in the Federal Register for 
public comment in the near future. The framework of the FMCSA Order is 
consistent with and reflects the procedures for considering 
environmental impacts under DOT Order 5610.1C. The FMCSA analyzed this 
proposal under the NEPA and DOT Order 5610.1C. Since the proposal is 
intended to put into place a means of measuring brake performance at 
roadside, but has no effect on brake standards, we believe it would be 
among the type of regulations that would be categorically excluded from 
any environmental assessment.

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.

Executive Order 13211 (Energy Effects)

    We have analyzed this action under Executive Order 13211, Actions 
Concerning Regulations That Significantly Affect Energy Supply, or Use. 
We have determined that it is not a ``significant energy action'' under 
that order because it is not economically significant and is not likely 
to have a significant adverse effect on the supply, distribution, or 
use of energy.

List of Subjects in 49 CFR Part 393

    Motor carriers, Motor vehicle equipment.

    In consideration of the foregoing, the FMCSA amends 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, for motor vehicles or motor vehicle 
combinations that have a GVWR or GVW greater than 4,536 kg (10,000 
pounds),
    (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 force at each wheel of 
the

[[Page 51778]]

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 and  Application and
            Type of motor vehicle             as a percentage  Deceleration in      braking          braking
                                                  of gross     feet per second    distance in      distance in
                                                 vehicle or       per second       feet from        feet from
                                                combination                      initial speed    initial speed
                                                   weight                          at 20 mph        of 20 mph
----------------------------------------------------------------------------------------------------------------
A. Passenger-carrying vehicles:
    (1) Vehicles with a seating capacity of              65.2               21               20               54
     10 persons or less, including driver,
     and built on a passenger car chassis...
    (2) Vehicles with a seating capacity of              52.8               17               25               66
     more 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                     43.5               14               35               85
     vehicles...............................
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                    53.5               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 drive-away or tow-
     away operation.........................
    (3) All other property-carrying vehicles             43.5               14               40              90
     and combinations of property-carrying
     vehicles...............................
----------------------------------------------------------------------------------------------------------------
Notes: (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 that 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.


     *COM019*Issued on: August 2, 2002.
Joseph M. Clapp,
Administrator.
[FR Doc. 02-20248 Filed 8-8-02; 8:45 am]
BILLING CODE 4910-EX-P