[Federal Register Volume 67, Number 131 (Tuesday, July 9, 2002)]
[Proposed Rules]
[Pages 45440-45444]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 02-17193]


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DEPARTMENT OF TRANSPORTATION

National Highway Traffic Safety Administration

49 CFR Part 571

[Docket No. 02-12643]
RIN 2127-AC66


Federal Motor Vehicle Safety Standards: Air Brake Systems

ACTION: Termination of rulemaking.

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SUMMARY: Brake blocks, also known as brake linings, are sacrificial 
components of brake systems. Composed of friction material, they are 
pressed against brake drums or brake rotors when a vehicle's brakes are 
activated. The composition and characteristics of brake blocks may vary 
considerably. This variation has a direct impact on brake performance 
and vehicle stopping distances. NHTSA received two petitions for 
rulemaking requesting issuance of standards for brake blocks, one from 
the American Trucking Associations (ATA) and the other from a private 
individual, Mr. Ralph Grabowsky. In March 1989, NHTSA granted the ATA 
petition and partially granted and partially denied Mr. Grabowsky's 
petition, agreeing to consider beginning rulemaking to develop a 
standard for marking, identifying and rating the effectiveness of heavy 
truck brake blocks. After granting these petitions, the agency 
initiated a number of studies to determine the feasibility of 
developing effectiveness ratings for heavy truck brake blocks. After 
examining the data developed from its research as well examining 
voluntary standards for heavy truck brake blocks, NHTSA has determined 
that it is unlikely that a suitable test procedure for comparing and 
rating brake blocks can be developed with currently available test 
equipment and procedures. Accordingly, the agency is terminating this 
rulemaking action.

FOR FURTHER INFORMATION CONTACT: For non-legal issues: Mr. Samuel 
Daniel Jr., Office of Crash Avoidance Standards, NPS-22, National 
Highway Traffic Safety Administration, 400 Seventh Street, SW, 
Washington, DC 20590, telephone (202) 366-4921, facsimile (202) 366-
4329, electronic mail [email protected].
    For legal issues: Mr. Otto G. Matheke, III, NCC-20, Rulemaking 
Division, Office of Chief Counsel, National Highway Traffic Safety 
Administration, 400 Seventh Street, SW, Washington, DC 20590, telephone 
(202) 366-2992,

[[Page 45441]]

facsimile (202) 366-3820, electronic mail [email protected].

SUPPLEMENTARY INFORMATION:

A. Background

1. ATA and Grabowsky Petitions

    On April 6, 1987, a private individual, Mr. Ralph Grabowsky, 
petitioned for rulemaking to establish a brake block standard for motor 
vehicles and equipment, covering stability, friction, fade, proper 
identification and wear. On August 11, 1987, the American Trucking 
Associations (ATA) petitioned for a standard that would require rating 
the effectiveness (coefficient of friction) of all heavy truck brake 
blocks, and to have that rating permanently marked on the block. In 
March 1989, NHTSA granted the ATA petition and that portion of the 
Grabowsky petition concerning the friction rating and identification of 
brake blocks for heavy-duty vehicles. The agency indicated that it was 
planning research investigations in the subject area and that 
information derived from those investigations would be used to help 
determine whether a notice of proposed rulemaking would be issued. 
NHTSA explained its denial of the other portions of the Grabowsky 
petition in a notice published in the Federal Register on July 11, 1989 
(54 FR 29067).
    The ATA petition indicated that the trucking industry believed that 
voluntary brake block effectiveness rating standards then in place were 
inadequate and that a federal standard would improve heavy truck 
stability and braking performance. The Grabowsky petition stated that a 
new federal standard for brake blocks would reduce deaths, injuries and 
economic losses resulting from traffic accidents.

2. SAE Test Procedures

    At the time the petitions were granted, NHTSA did not have any 
standard governing the rating and marking of brake blocks. Several 
voluntary standards were in place. The Society of Automotive Engineers 
(SAE) recommended practice for rating heavy-duty vehicle brake block 
performance, SAE Recommended Practice J661a--Brake Block Quality 
Control Test Procedure was one such standard. The SAE also had a 
recommended practice for marking heavy vehicle brake blocks with 
performance data based on the results from the J661a procedure. This 
SAE Recommended Practice, J866--Friction Coefficient System For Brake 
Blocks, designated the normal temperature and high temperature 
performance of given block material, and specified procedures for 
printing the J661 performance ratings on the edge of the block.
    Based on its evaluations of the J661a test procedures, the trucking 
industry concluded that the levels of repeatability and reproducibility 
of the SAE standards were unacceptably low. Additionally, the trucking 
industry determined that the test procedure was not realistic since it 
did not use a full-scale brake block or other full-scale heavy-duty 
vehicle brake hardware. The J866 specifications and ratings were also 
deemed unacceptable. According to ATA, a given SAE J866 rating covered 
such a wide range of brake block performance that vehicle brake balance 
problems were possible using blocks with the same rating. In addition, 
the J866 procedure for marking the blocks did not result in permanent 
markings. As a result, vehicle operators and maintenance personnel 
often could not identify the performance ratings on in-service blocks.
    Since the SAE recommended practices for testing brake block 
effectiveness and the procedure for marking the blocks with an 
effectiveness value were unacceptable to the industry, the SAE 
initiated the development of new procedures in the mid-1980s. At that 
time, the SAE Brake Committee, Brake Effectiveness Task Force, 
initiated development of a new procedure for evaluation of the 
effectiveness of heavy vehicle brake blocks, SAE Recommended Practice 
J1802--Brake Block Effectiveness Rating. The SAE began development of a 
new specification for rating the effectiveness of brake blocks and 
permanently labeling the blocks with information concerning the 
effectiveness (torque output), SAE J1801, Brake Effectiveness Marking 
for Brake Blocks.
    The SAE J1802 test procedure is a dynamometer test procedure to be 
used to compare frictional properties of brake blocks. The test 
conditions specify a reference full-scale air brake assembly of 16.5 
in. X 7.0 in. that utilizes S-cam actuation. The test is initiated with 
a burnish procedure requiring 200 stops with a 9.8 ft/sec \2\ 
deceleration and with an initial brake temperature of 392 deg. F for 
each stop. The burnish procedure is followed by the normal temperature 
test for brake effectiveness, which specifies stops at brake chamber 
pressures of 10, 15, 20, 25, 30, 35, 40, 45, and 50 psi, with an 
initial brake temperature for each stop of 212 deg. F. A high 
temperature test for brake effectiveness is conducted after the normal 
temperature test, using the same procedure as the normal temperature 
test with the exception of initial brake temperature, which is 572 deg. 
F. for each stop. The brake output torque and brake input torque are 
recorded for each stop from the time the specified air pressure is 
reached until the brake stops. The SAE J1802 brake effectiveness rating 
is a calculated, non-dimensional quantity that relates the average 
output torque determined in the procedure, to the average input torque. 
In order to make the friction ratings available to end users, SAE J1801 
specifies that the actual normal temperature and high temperature brake 
effectiveness values obtained from J1802 testing be engraved to a depth 
of 0.2 mm on one side or edge of the brake block (block).

3. Agency Efforts To Develop A Rating

    In 1990, NHTSA began working with SAE and the Heavy-duty Brake 
Manufacturers Council (HDBMC) in the development and evaluation of SAE 
J1801 and J1802 and the development of possible improvements to them. 
In that year, dynamometer testing to an early version of J1802, was 
conducted by three different test facilities using their own funds 
(Greening Labs, Link Engineering, and Vehicle Research and Test 
Center). The testing produced significantly different effectiveness 
ratings for brake blocks that were manufactured to have essentially the 
same performance characteristics. It could not be determined from this 
testing whether the differences in effectiveness ratings were due to 
the variations in actual block performance, differences in test 
fixtures, or differences in the dynamometers at each facility.
    In order to determine the cause of the significant differences in 
the ratings of brake block effectiveness produced by the three 
facilities, a round-robin series of brake block testing was conducted. 
Nine organizations with brake dynamometer testing facilities, including 
the agency's Vehicle Research and Test Center (VRTC), volunteered to 
participate in the project using their own funds. For this testing, 
which was conducted in 1991-1992, a single test fixture that included a 
brake drum and brake blocks was tested at each facility. After 
completion of testing at one facility, the brake assembly and brake 
blocks were forwarded to another of the participating facilities. The 
primary purpose of this series of tests was to determine the 
variability of the test results due to differences in the dynamometers 
at each facility. The test results revealed a small (10-15%) variation 
in test results that could be attributed to the differences in the 
dynamometers at each facility.
    Based on the results of the single fixture testing results, VRTC 
conducted

[[Page 45442]]

a second series of voluntary round-robin testing in 1992 and 1993 to 
evaluate the repeatability and reproducibility of the J1802 test 
procedure. Six brake testing facilities participated in this test 
series, which involved determining the normal and high temperature 
brake effectiveness ratings for three brake block materials using the 
J1802 test procedure. Each facility was supplied with a brake drum and 
several sets of blocks. The blocks supplied to each facility by a given 
manufacturer were from the same batch or block manufacturing cycle. 
Although the entire test series was not completed by all participants, 
sufficient data were produced for the agency to determine that there 
was as much as a 50% variation of the effectiveness ratings for the 
same brake block material when tested at different facilities, and a 
20% variation in the effectiveness ratings for the same block material 
during different tests at the same facility.
    The first round-robin test series indicated that the differences in 
the test facility dynamometers resulted in as much a 10-15% difference 
in brake block effectiveness values. The increased variation in 
effectiveness ratings experienced in the second round-robin was 
attributed to other test parameters such as test fixture, the method of 
brake assembly installation on the test fixture, and the brake 
preparation (brake burnishing and brake block grinding).
    Additional SAE J1802 research was conducted in 1993-1994 by VRTC 
with the coordination from HDBMC. These tests were conducted to study 
the effects of block burnishing and pre-test grinding procedures on the 
variability in effectiveness demonstrated in the second round-robin 
test series. The results indicated that neither the burnishing nor 
grinding of the blocks eliminated variability in brake effectiveness 
ratings. The pattern of large variations in the SAE J1802 effectiveness 
ratings from one test facility to the other was unaffected when 
different burnishing and grinding techniques were used to prepare the 
blocks for testing.
    The 1990-1994 testing by VRTC and other brake test facilities led 
NHTSA to believe that the SAE J1802 test procedure lacked the 
repeatability and reproducibility that is needed for federal safety 
standards. The agency further concluded that the problems were not 
minor, and considerable time and resources would likely be necessary to 
solve them. For these reasons, NHTSA decided in 1994 against 
incorporating the SAE J1802 test procedures into the federal brake 
performance requirements.
    In 1996, NHTSA initiated a project aimed at developing a brake 
block rating scheme that could be used to provide information to 
consumers about the effectiveness of heavy truck brake blocks. A one-
year feasibility project was conducted at VRTC, which developed several 
effectiveness test components and test procedures that were different 
from those in SAE J1802. These differences included variations in 
burnish cycles, the number of effectiveness stops, and block pre-
cutting profiles. New test fixture components and effectiveness test 
procedures were used to test one original equipment brake block and 
several aftermarket blocks. Although the VRTC-developed fixture and 
procedure were successful in eliminating some of the effectiveness 
variability experienced with SAE J1802, the modified procedure still 
resulted in considerable variation in block effectiveness. There was a 
20-30% variation in effectiveness rating results when a single brake 
block was tested 10 consecutive times with the new brake components and 
modified procedures. VRTC then evaluated the variability that might 
result from using different brake blocks. An original equipment block 
and two aftermarket brake blocks recommended as replacement blocks were 
tested. The variability of the effectiveness rating for the original 
equipment block was about 10%. The variability of the test results for 
the two aftermarket replacement blocks was 18-25% for one block and 8-
25% for the other.
    In 1997, NHTSA reviewed the previous J1802 evaluation projects and 
the NHTSA 1996 research project designed to develop an improved rating 
procedure for heavy-duty brake block torque effectiveness. The agency 
decided to examine the SAE J1802 procedure further and determine what, 
if any modifications would be required to improve the consistency of 
the test results. A VRTC project, entitled ``S-Cam Brake Effectiveness 
Comparison Using Two Fixtures and Two Block Types on a Single Inertia 
Dynamometer,'' examined the effect of using two different test fixtures 
on the SAE J1802 brake effectiveness ratings. The project was initiated 
in 1998 and the draft final report was circulated for comment within 
the agency in January 2000. Measurements were taken on several 
components of the two SAE J1802 test fixtures including the S-cam 
profile, the chamber force-displacement calibrations, and brake spider 
position. VRTC determined that the measured differences in these brake 
fixture dimensions and performance characteristics were minimal. The 
two fixtures were then used to test two different sets of brake blocks 
from two different manufacturers. To eliminate potential sources of 
variation in the test results, the testing was conducted with the same 
operator and dynamometer. A limited number of tests indicated that the 
test fixtures, which were used in previous SAE J1802 testing, did not 
contribute significantly to the 10.2% variation in effectiveness 
ratings. Results from previous SAE J1802 testing indicated the 
existence of several potential causes for variation in block 
effectiveness ratings including the dynamometer, operator, test set-up 
procedures, and brake block and/or brake drum material differences.
    A computer study funded by the Federal Highway Administration 
(FHWA) examined the effect of several S-cam type brake parameters on 
the brake output torque (effectiveness). This computer simulation 
study, conducted by the University of Michigan Transportation Research 
Institute (UMTRI), and completed in 1999, found that small variations 
in the test fixtures could cause significant changes in brake output 
torque. The study further stated that the brake equilibrium reached 
during burnish could be disturbed when brake actuation pressure is 
above or below the burnish pressure. This non-equilibrium condition, 
caused by differential block wear between the leading and trailing 
block at equilibrium, may result in the instability of the brake 
effectiveness ratings experienced in the SAE J1802 testing. The study 
concluded by recommending that the computer model be extended to 
include block wear properties to further examine the SAE J1802 brake 
effectiveness variations.

B. Discussion

    As discussed above, NHTSA, FHWA, SAE, and ATA have conducted 
research over the past 10 years to develop test devices and repeatable, 
reliable, and reproducible test procedures suitable for the development 
of heavy vehicle brake block performance ratings. Much of the research 
activity has focused on the SAE J1802 procedure, which was originally 
developed in the mid-1980s. Testing conducted in accordance with the 
SAE J1802 procedures from 1990 through 1994 resulted in brake block 
effectiveness ratings that vary by up to 50% when a given block is 
tested at different facilities. Even when a given brake block was 
subjected to repeat testing at the same facility, test results varied 
by as much as 20 percent. This level of variability may be acceptable 
for some applications, but is unacceptably

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high for a federal brake block effectiveness rating. Agency efforts 
made in 1994 and 1995 to reduce this variability were unsuccessful. 
Further efforts to develop a reliable test procedure, including the 
1996 VRTC alternative test scheme study, the VRTC ``S-cam brake 
comparison study'' and the UMTRI ``S-cam brake computer sensitivity 
study'' have not reduced this unacceptably high level of variability.
    Although SAE J1802 was published in 1993, the research conducted by 
NHTSA and the other test facilities has consistently indicated that the 
procedure is not highly accurate at measuring brake block torque 
output. Consequently, very few brake blocks are marked according to the 
marking procedure specified in SAE J1801. Resistance to use of the 
J1802 rating and the J1801 markings is based on the belief that the 
J1802 ratings suffer from high variability in test results and are not 
a good predictor of brake block effectiveness.
    As a result of the slow progress of SAE J1802 development, the ATA 
Maintenance Council developed a Recommended Practice (RP) for rating 
the torque capacity of replacement brake blocks and issued this 
practice, RP 628, in 1995. The RP 628 uses the dynamometer test 
procedure in Federal Motor Vehicle Safety Standard (FMVSS) No. 121, Air 
Brake Systems to ensure that replacement brake blocks meet the same 
requirements as brake blocks for new vehicles. The Maintenance Council 
and the SAE periodically publish a list of blocks that meet all the 
FMVSS No. 121 dynamometer test performance requirements. The 
publications also include the brake output torque measured during a 40-
psi constant-brake-chamber-pressure stop to allow comparison of the 
torque output capacity (effectiveness) of different brake blocks. It 
was recognized that this procedure had a number of shortcomings and was 
intended to be an interim procedure. However, RP628 is currently the 
procedure used most often by brake block manufacturers to evaluate the 
torque output performance of heavy vehicle, domestic blocks.
    Although the Economic Commission for Europe (ECE) has developed a 
brake block standard, this standard does not provide much guidance for 
developing a standard suitable for conditions in the U.S. The ECE has 
procedures for evaluating the torque output performance of replacement 
brake blocks for powered vehicles and trailers, which are contained in 
ECE Regulation No. 90 (R90), ``Uniform Provisions Concerning the 
Approval of Replacement Brake Block Assemblies and Drum Brake Blocks 
for Power-Driven Vehicles and Their Trailers.'' In general, replacement 
blocks for heavy trucks, buses, and trailers may be evaluated by 
installing the blocks on a vehicle for which they are designed and 
conducting portions of the brake testing specified in ECE Regulation 
13, ``Uniform Provisions Concerning the Approval of Vehicle Categories 
M, N, and O With Regard to Braking.'' Replacement blocks are approved 
for use only on the type of vehicle tested if the ECE R13 performance 
requirements are met. Replacement blocks may also be tested for 
approval either through an inertia dynamometer test procedure or a 
rolling bench test. If the dynamometer test or the rolling bench test 
is used to obtain approval for replacement blocks, original equipment 
blocks for the same type of vehicles must also be tested with the 
dynamometer or rolling bench procedure. Approval of the replacement 
blocks is based on a comparison between the test results of the 
replacement blocks and the original equipment blocks.
    To date, none of the ECE member countries or Japan has voluntarily 
adopted the R90 procedures and requirements for heavy truck, bus, or 
trailer replacement brake blocks. The ECE R90 requirements were 
scheduled to become effective in all European Economic Commission (EEC) 
member countries, in the form of EEC Directive 98/12, in the mid-2000s. 
There are several issues surrounding the implementation of ECE 
Directive 98/12 for heavy trucks and trailers that are currently being 
addressed. According to EEC Directive 98/12 (ECE R90), brake blocks for 
heavy vehicles are to be packaged in full axle sets (brake blocks for 
left and right side wheels in the same package). These packages must be 
handled mechanically due to their weight and consequently, 
transportation and handling of these packages will be difficult unless 
there are some adjustments to the packaging requirements. Additionally, 
the European friction material manufacturers do not generally assemble 
the blocks to the brake shoes. As a result, mismatching of shoe-block 
attachment hardware (rivets and rivet bore sizing) is also an issue. As 
noted, the regulation requires that the performance of replacement 
blocks be compared to the performance of original equipment blocks if 
the dynamometer or rolling bench tests are used for approval. The 
specific tests and compliance requirements for these tests have not 
been finalized to date.
    As previously stated, the agency does not consider the EEC 
Directive 98/12 (ECE R90) test procedures and performance requirements 
as suitable for application in the U.S. The full-scale vehicle test 
using older model vehicles equipped with new replacement parts is 
costly and time-consuming. In addition, this testing only assesses 
brake block performance in a specific vehicle. To date, test procedures 
and compliance requirements for the dynamometer test and the rolling 
bench test in Europe have not been finalized. We have asked the 
European governments and industry, at the ECE meetings of the Working 
Party on Brakes and Running Gear (GRRF), for any research data, tests, 
or other findings that they may have, which could assist NHTSA in 
developing an acceptable test for brake block effectiveness. They 
indicated that they did not have any such data.
    In considering whether to commence a rulemaking action in this 
case, NHTSA notes that the continuing difficulties encountered in 
developing an acceptable brake block effectiveness test indicate that 
an acceptable test is elusive. Further, in deciding whether to continue 
this effort, and to expend agency resources in furtherance of this 
effort, the agency must also consider the safety problem to be 
addressed by a brake block effectiveness standard and whether other 
means are available to address that problem. ATA's petition for 
rulemaking indicated that heavy vehicle wheel lockup and the resultant 
potential for instability was one of the primary concerns it sought to 
have the agency address through a brake block effectiveness rule. In 
theory, using brake blocks with a similar effectiveness on each axle 
can reduce the risk of instability in situations where brake blocks 
with different friction characteristics would cause braked wheels to 
decelerate at different rates. Wheel lockup can have a severe impact on 
vehicle control and stability, particularly in heavy trucks and truck-
trailer combinations under slippery roadway conditions.
    NHTSA believes that there are safety benefits that would be 
associated with the issuance of a heavy vehicle brake block performance 
rating standard, although we are not aware of any study that has 
quantified these benefits. As a result, the agency does not believe the 
research in this area should be terminated, although the current 
problems will not be readily solved based on the experience of the past 
10-12 years. The agency wants to be clear on the fact that only the 
rulemaking activities are being terminated, not the research. In fact, 
as proposed by the Senate, the agency's fiscal year 2002 budget 
includes $300,000.00 for

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research into brake lining friction. A reliable rating system would 
allow vehicle users to select brake blocks with similar wear and 
performance characteristics. A reliable rating system would also allow 
users to select a block appropriate for the expected use of the 
vehicle. However, the most recently completed research projects 
indicate that considerably more research is required to improve the 
reliability of existing test procedures or to develop another 
acceptable procedure.
    Further, the agency notes that heavy truck stability under braking 
has been addressed by a means other than a brake block effectiveness 
rating standard. In March 1995, the agency issued final rules requiring 
antilock brake systems (ABS) on heavy-duty vehicles including air 
braked truck tractors, trucks and buses, and hydraulically braked 
trucks and buses (60 FR 13216, March 10, 1995). The rule became 
effective for air-braked truck tractors in March 1997. For air-braked 
trailers, single unit trucks and buses, the requirements for ABS became 
effective in March 1998. The ABS requirements for hydraulically-braked 
trucks and buses became effective in March 1999. NHTSA believes that 
the ABS requirements will significantly reduce wheel lockup and the 
resultant potential for vehicle instability. ABS reduces the vehicle 
instability that results from brake imbalance because it modulates the 
brake torque to prevent lockup at each wheel or axle where it is 
installed. ABS does not address or alleviate all safety concerns 
related to differential brake block performance such as stopping 
distance performance. However, the ABS requirement improves vehicle 
stability during braking, which is the primary concern expressed by ATA 
in the original petition.
    Due to the substantial technical obstacles that still remain in 
regard to development of a test procedure and the advent of ABS 
requirements that, in part, address the safety need that would be met 
by a brake block effectiveness rating, NHTSA has determined that 
further rulemaking action on the Grabowsky and ATA petitions is 
unwarranted. However the agency does not believe that research and 
evaluation of a dynamometer-based procedure for evaluating the torque 
output of heavy vehicle brake blocks should be terminated.

C. Agency Determination

    For the reasons stated above, NHTSA is terminating this rulemaking 
action.

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

    Issued on: July 3, 2002.
Stephen R. Kratzke,
Associate Administrator for Safety Performance Standards.
[FR Doc. 02-17193 Filed 7-8-02; 8:45 am]
BILLING CODE 4910-59-P