Federal Motor Vehicle Safety Standards; Burnish Procedures for Heavy Vehicles

DEPARTMENT OF TRANSPORTATION

National Highway Traffic Safety Administration

49 CFR Part 571

[Docket No. 70-27, Notice 33 and Docket No. 83-07, Notice 7]

RIN 2127-AF13

Federal Motor Vehicle Safety Standards; Burnish Procedures for

Heavy Vehicles

AGENCY: National Highway Traffic Safety Administration (NHTSA),

Department of Transportation.

ACTION: Termination of rulemaking proceeding.

-----------------------------------------------------------------------

SUMMARY: This notice terminates rulemaking to amend Standard No. 105,

Hydraulic Brake Systems, and Standard No. 121, Air Brake Systems, with

respect to the burnish procedures for medium and heavy vehicles. The

agency has determined that it would be unnecessary to extend the period

during which a manufacturer may choose between two burnish procedures

since manufacturers have been certifying compliance to the brake

standards based on the ``new'' more representative burnish procedure

since September 1994.

FOR FURTHER INFORMATION CONTACT: Mr. Richard C. Carter, Office of

Vehicle Safety Standards, National Highway Traffic Safety

Administration, 400 Seventh Street, SA., Washington, DC 20590. (202-

366-5274).

SUPPLEMENTARY INFORMATION:

I. Background

Standard No. 105, Hydraulic Brake Systems, and Standard No. 121,

Air Brake Systems (49 CFR 571.121), specify tests to measure whether

medium and heavy vehicles 1 equipped with hydraulic or air brakes

comply with the standards' performance requirements. These vehicles are

subject to ``burnish'' procedures conducted at the outset of road

testing and dynamometer testing. The burnish procedures serve to

simulate the breaking-in of the brakes on new vehicles under normal

driving conditions.

\1\ Hereafter, referred to as heavy vehicles.

---------------------------------------------------------------------------

Until September 1, 1994, the standards contained old and new

burnish procedures, identified in the standards as option ``a'' and

option ``b,'' respectively. The old burnish procedure consisted of a

series of brake applications, known as ``snubs,'' that result in the

brakes being heated to not more than the specified maximum temperature

of 550 deg.F.

In response to a petition from International Harvester, the agency

amended the burnish procedures in a final rule published on March 14,

1988 (49 FR 8191). The agency initiated rulemaking because the

temperature limit, which was established with drum brake designs in

mind, appeared inappropriate for disc brake designs. Disc brake systems

are designed to operate at appreciably higher temperatures than are

drum brake systems. As a result, it had been difficult to avoid

exceeding the specified maximum temperature during the burnish of

vehicles with disc brake systems.

After issuing several notices, the agency added a new burnish

procedure in 1988 providing that the brakes on heavy duty vehicles are

to be burnished by 500 snubs slowing the vehicle from 40 mph to 20 mph,

without regard to [[Page 25881]] brake temperatures generated during

the burnish. NHTSA believes that under the new burnish procedure,

brakes will be burnished in a manner that is more realistic and

representative of the breaking-in that vehicle brakes actually receive

in service without favoring drum brake designs over disc brake designs.

NHTSA allowed a five-year transition period for implementing the

new burnish procedure. The agency provided this longer than normal lead

time to minimize the rulemaking's cost impact by allowing manufacturers

to phase-in any required changes to brake systems as design changes

were made. During the transition period, manufacturers could choose

between the old and new burnish procedures. As established in the 1988

final rule, the period lasted until September 1, 1993. On and after

that date, the only burnish procedure in the standards was to be the

new one.

II. Petitions

NHTSA received petitions from Eaton Corporation and the American

Automobile Manufacturers Association (AAMA) concerning the effective

date for the new burnish procedure. Eaton petitioned the agency either

to permit the old burnish procedure as an option indefinitely or at

least to postpone the date on which the new procedure became the only

procedure, to allow the agency to investigate problems associated with

that procedure.

The AAMA petitioned NHTSA to delete the effective date for the new

brake burnish procedure. If AAMA's request were granted, a choice

between the old and new burnish procedures would be allowed

indefinitely. AAMA stated that specifying only the new procedure would

result in increased variability that could adversely affect brake

effectiveness. The petitioner also believed that the new procedure

would increase the stringency of the parking brake requirements

because, it claimed, braking performance generally degrades at lower

burnish temperatures. In addition, AAMA stated that many current

vehicles that comply with the brake standards after being subjected to

the old burnish procedure will not comply when tested after being

subjected to the new burnish procedure. It suggested that this

noncompliance was not indicative of a safety problem, noting that it is

not aware of any safety problem arising from the braking performance of

vehicles tested after using the old procedure.

After receiving these petitions, NHTSA staff met with

representatives of Eaton, Freightliner, PACCAR, Navistar, Rockwell,

Lucas, Carlisle, and Ford.2 According to these representatives of

the heavy truck industry, the new burnish procedure would result in

significant variability problems and potential compliance problems.

Accordingly, they requested that NHTSA either (1) Delay the September

1, 1993 effective date, (2) allow either procedure indefinitely, or (3)

develop a new burnish procedure.

\2\ A memo has been placed in the docket summarizing these

meetings.

---------------------------------------------------------------------------

III. Interim Final Rule and Notice of Proposed Rulemaking

On August 30, 1993, NHTSA published two notices in response to the

petitions for rulemaking from Eaton and AAMA: an interim final rule

extending the period during which either the old or new burnish

procedures could be used until September 1, 1994 (58 FR 45459); and a

notice of proposed rulemaking (NPRM) proposing to extend the optional

period for the new burnish procedure an additional 18 months to March

1, 1996. (58 FR 45476)

In justifying these notices, NHTSA explained that the March 14,

1988 final rule was not intended to impose additional or more stringent

performance requirements for heavy vehicles. Instead, the adoption of

the new burnish procedure was intended to ensure that the compliance

tests are more representative of actual vehicle break-in and to

eliminate the current burnish procedure's bias against new brake

designs.

NHTSA stated that the time period during which either burnish

procedure may be used should be extended. The agency explained that

without the delay to September 1, 1994, vehicle manufacturers would

have faced a significant cost burden related to compliance testing and

product development, without corresponding safety benefits. The agency

further explained that, under a February 23, 1993 proposal to reinstate

stopping distance requirements for heavy vehicles, manufacturers would

have had to conduct two sets of compliance testing using both the old

and new burnish procedures within the comment period. (58 FR 11003,

11009). It further explained that the agency needed to assess the

petitioners' contention that the new burnish procedures result in a

more stringent requirement.

In response to the proposal to extend the optional burnish

procedure until March 1, 1996, the agency received comments from AAMA,

the Heavy Duty Brake Manufacturers Council (HDBMC), Ford, General

Motors (GM), Chrysler, and four brake manufacturers (Eaton, Rockwell

International, Lucas, and Midland-Grau. The commenters requested that

vehicle manufacturers be permitted to use either the old or new burnish

procedure indefinitely.

AAMA submitted test data on the braking performance of combination

vehicles, including a vehicle tested at NHTSA's Vehicle Research

Testing Center (VRTC). AAMA stated that these tests indicate that the

proposed stopping distance requirements and braking-in-a-curve test

could not be consistently met unless the initial brake temperature was

reduced to between 150 deg.F and 200 deg.F from 250 deg. and 300 deg.F.

Specifically, AAMA said that the proposed increase in initial brake

temperature 3 would cause an increase in stopping distance, and

thus would cause a vehicle to fail to comply with the proposed stopping

distance requirements.

\3\ In the stopping distance NPRM, NHTSA proposed an initial

brake temperature of 250 deg.F to 300 deg.F. However, in the final

rule the agency concluded that an initial brake temperature of

between 150 deg.F to 200 deg.F is more appropriate. 60 FR 13292.

---------------------------------------------------------------------------

As explained above, the new burnish procedures took effect on

September 1, 1994. Since that date, vehicle manufacturers have been

required to certify compliance to the braking standards using the new

burnish procedures and have not been permitted to burnish brakes using

the old procedures. In proposing to extend optional compliance with the

old procedure until March 1996, the agency sought to simplify

compliance for vehicle manufacturers by only having them conduct the

braking tests once if they relied on the old burnish procedures.

However, this consideration became moot because the new burnish

procedures went into effect in September and the agency was unable to

issue the stopping distance and stability and control rulemakings prior

to that date.

Based on these considerations, NHTSA has decided to terminate the

burnish rulemaking that would have permitted optional compliance to the

old burnish procedures until March 1, 1996. As explained in the

stopping distance final rule, ``vehicle manufacturers have had

sufficient time to conduct any additional testing and to make any

necessary design changes in order to meet the requirements of Standard

No. 121, with the new burnish procedures.'' (60 FR 13286, 13292) As a

result, vehicles must be burnished pursuant to the new brake burnish

procedure set forth in S7.4.2.1(b) of Standard No. 105 and in

S6.1.8.1(b) of Standard No. 121.

[[Page 25882]] NHTSA believes that the new burnish procedure is

more valid because it has a lower energy input level that is closer to

the burnish achieved in actual use. Accordingly, it would be

inappropriate to permit the old procedure indefinitely. The agency

further believes that achieving compliance using the new burnish

procedure is feasible given the industry's considerable progress in

developing new brake linings that can meet the brake system performance

requirements when using the new burnish procedures. The agency notes

that the additional year allowed by the interim final rule, together

with the initial five year transition period, provided ample time for

vehicle and brake manufacturers to evaluate brake block materials.

NHTSA believes that there is only very limited validity to the

manufacturers' argument that the new burnish procedure is more

stringent. The objections to the new burnish procedure come from those

manufacturers whose existing brake systems have to be burnished to peak

perfection in order to pass the minimum requirements. The new burnish

procedure is more stringent only in the sense that it does not produce

temperatures that are as high as the old procedure and in the sense

that the lower temperature of the burnish reduces brake performance.

NHTSA notes that brake manufacturers are continuing to develop brake

block materials that are less sensitive to burnish and do not require

high temperatures of the old burnish to complete the manufacturing

process. As these materials are developed, the new procedure's already

limited effect will become progressively smaller.

Authority: 49 U.S.C. 322, 30111, 30162; delegations of authority

at 49 CFR 1.50 and 501.8.

Issued on: May 10, 1995.

Barry Felrice,

Associate Administrator for Safety Performance Standards.

[FR Doc. 95-11927 Filed 5-12-95; 8:45 am]

BILLING CODE 4910-59-P