Parts and Accessories Necessary For Safe Operation; Automatic Brake Adjusters and Brake Adjustment Indicators

DEPARTMENT OF TRANSPORTATION

Federal Highway Administration

49 CFR Part 393

[FHWA Docket No. MC-94-9]

RIN 2125-AD37

Parts and Accessories Necessary For Safe Operation; Automatic

Brake Adjusters and Brake Adjustment Indicators

AGENCY: Federal Highway Administration (FHWA), DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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

SUMMARY: The FHWA is proposing to require the use of automatic brake

adjusters (ABAs) on hydraulically-braked commercial motor vehicles

(CMVs) and air-braked CMVs manufactured on or after October 20, 1993,

and October 20, 1994, respectively. The FHWA is also proposing a

requirement for brake adjustment indicators on air-braked CMVs with

external adjustment mechanisms manufactured on or after October 20,

1994. This rulemaking is intended to: Insure that the operational

standards for brakes in the Federal Motor Carrier Safety Regulations

(FMCSRs) are consistent with the manufacturing standards in the Federal

Motor Vehicle Safety Standards (FMVSSs) numbers 105 and 121, which now

require the installation of automatic brake adjusters and adjustment

indicators on certain CMVs manufactured on or after these dates; and

improve the safety of operation of CMVs by reducing the incidence of

brakes that are out of adjustment.

In addition, the FHWA requests information concerning the

possibility of requiring these devices to be retrofitted to CMVs placed

in operation prior to the effective dates of the recent amendments to

FMVSS Nos. 105 and 121.

DATES: Comments must be received on or before October 3, 1994.

ADDRESSES: Submit written, signed comments to FHWA Docket No. MC-94-9,

room 4232, HCC-10, Office of the Chief Counsel, Federal Highway

Administration, 400 Seventh Street, SW., Washington, D.C. 20590. All

answers to questions should refer to the appropriate question number

and all comments on specific provisions should refer to the appropriate

section and paragraph number. All comments received will be available

for examination at the above address from 8:30 a.m. to 3:30 p.m., e.t.,

Monday through Friday, except Federal holidays. Those desiring

notification of receipt of comments must include a self-addressed,

stamped postcard.

FOR FURTHER INFORMATION CONTACT: Ms. Deborah M. Freund, Office of Motor

Carrier Standards, (202) 366-2981, or Mr. Charles Medalen, Office of

the Chief Counsel, (202) 366-1354, Federal Highway Administration,

Department of Transportation, 400 Seventh Street, SW., Washington, D.C.

20590. Office hours are from 7:45 a.m. to 4:15 p.m., e.t., Monday

through Friday, except Federal holidays.

SUPPLEMENTARY INFORMATION:

Background

A. General Information

Proper brake adjustment is critical to the safe operation of

commercial motor vehicles. When brakes are correctly adjusted, vehicles

can generally be brought to a stop within a satisfactory distance and

in a controlled manner. However, brakes that are not properly adjusted

cannot develop the retardation force designed into the vehicle's brake

system, resulting in increased stopping distances. Under emergency

conditions, this can result in a collision that might otherwise have

been avoided, or in a more severe collision than would have occurred

with properly-adjusted brakes.

Out-of-adjustment brakes are the primary equipment-related cause

for commercial motor vehicles to be placed out of service during

roadside inspections. According to the FHWA's Office of Motor Carrier

Field Operations Annual Report for Fiscal Year 1992, 36.2 percent of

vehicles placed out-of-service are cited for this deficiency. A copy of

this report has been placed in the docket.

In addition, brake-related accidents, some stemming from gross

brake maladjustment, are also a factor in some ``equipment

malfunction'' CMV accident citations. The National Highway Traffic

Safety Administration's (NHTSA) regulatory evaluation, prepared in

conjunction with their rulemaking on automatic brake adjusters (ABAs),

noted that 6.8 percent of all medium and heavy truck accidents were

reported as being caused by defective equipment. Of that figure, 31

percent were due to defective brakes, with 60 percent of those brakes

judged to be out of adjustment; this amounts to 1.3 percent of

accidents reported--or nearly 4,000 accidents per year. The regulatory

evaluation also cited a review of National Transportation Safety Board

(NTSB) reports on 97 serious heavy truck accidents investigated from

1969 to 1981. Out-of-adjustment brakes were cited as a causal or

contributing factor in 27 of those 97 accidents, or 28 percent. A copy

of the NHTSA's regulatory evaluation has been placed in the docket.

B. Safety and Operational Role of Automatic Brake Adjusters and Brake

Adjustment Indicators

Automatic brake adjusters significantly reduce the effort required

for inspection and manual adjustment of the brakes. Clearance-sensing

ABAs limit the clearance between brake linings and drums, or pads and

rotors, to a level that ensures effective brake actuator strokes. They

adjust on every complete brake application. Stroke-sensing ABAs adjust

on brake applications severe enough to cause the brake actuator stroke

to exceed that which the ABA is designed to maintain. ABAs include, but

are not necessarily limited to, automatic slack adjusters (ASAs). The

term ``automatic brake adjusters'' is used to provide a performance-

based description of this class of devices.

Brake adjustment indicators (BAIs), especially when used in concert

with ABAs, can do a great deal to address the brake adjustment problem.

A BAI conforming to the NHTSA requirements can significantly reduce the

time necessary to assess brake adjustment levels. Use of these

indicators will make it easier for drivers and maintenance personnel to

make brake-adjustment checks at more frequent intervals, and detect

brake adjustment problems before they become severe enough to cause, or

worsen the outcome of, an accident.

C. NHTSA and NTSB Research on CMV Brake Performance and ABAs.

Two extensive research studies of CMV brake performance, and

operational and maintenance experiences of motor carrier fleets

utilizing CMVs equipped with ABAs, have been performed by the NHTSA and

the NTSB. We summarize both here. Copies of the NHTSA and the NTSB

studies are available from the National Technical Information Service

(NTIS, Springfield, Virginia, telephone (800) 553-6847). Copies have

also been placed in the public docket.

1. NHTSA Research. The NHTSA research was reported in ``Automatic

Brake Adjusters for Heavy Vehicle Air Brake Systems,'' February 1991,

report DOT-HS-807-724 (PB 91-215814). Seven fleets participated during

a 2.5-year initial study period and an additional 3 years of follow-up;

245 tractors and 289 trailers accumulated nearly 50 million miles of

travel during this time.

Researchers and fleet maintenance staffs made nearly 20,000

measurements of brake stroke length on approximately 1,800 brake

adjusters (four different manufacturers' ABAs, plus manual brake

adjusters (MBAs)). For 36 types of ABA installations, the median out-

of-adjustment rate was 4.0 percent, and the median number of out-of-

adjustment observations per brake per 10,000 miles was 0.016. The NHTSA

noted that ``[t]he ASAs tested were principally models designed and

marketed in the early to mid 1980's. There have been extensive design

improvements in both ASAs and other brake system components since that

time. Thus, the performance data presented here for these earlier ASA

designs likely understate the performance levels that can be expected

from ASAs purchased today.''

The NHTSA collected a limited amount of control data on MBAs. There

were 96 MBAs used in portions of 3 of the fleets. The use of MBAs

generally resulted in higher percentages and rates of out-of-adjustment

brakes than did the use of ABAs, and the differences were considered to

be statistically significant.

2. NTSB Research. The NTSB, an independent Federal agency

responsible for investigating and determining the probable cause or

causes of certain transportation-related accidents, has studied

numerous accidents in which brake deficiencies have been cited as

causal factors.

A recent NTSB study, ``Heavy Vehicle Airbrake Performance,''

adopted April 29, 1992, report NTSB/SS-92/01 (PB 92-917003), analyzed

information gathered over a 17-month period from selected brake-related

accidents involving heavy trucks and buses, as well as data collected

by NTSB staff during roadside inspections in 5 States. The report's

findings highlighted the role of brake system components in certain

vehicle instability accidents, and pointed out that many brake out-of-

adjustment problems were due both to the small tolerance range and to a

lack of proper brake maintenance. The NTSB recommended that the DOT,

among other things: (1) Require air-braked vehicles to be equipped with

visible adjustment indicators that will allow one person to check the

level of adjustment (Recommendation H-92-50); (2) require automatic

adjusters on vehicles equipped with airbrake systems (Recommendation H-

92-51); and (3) encourage the installation of visible brake adjustment

indicators on all vehicles equipped with air brake systems for easy

detection of adjustment levels (Recommendation H-92-57).

D. NHTSA Requirement for ABAs and Automatic Adjustment Indicators

The FHWA strives to maintain consistency between the manufacturing

standards for commercial motor vehicles contained in the NHTSA's

Federal Motor Vehicle Safety Standards (FMVSSs), and the operations and

maintenance regulations contained in the FMCSRs. On October 20, 1992

(57 FR 47793), the NHTSA issued a final rule amending FMVSS No. 105,

Hydraulic Brake Systems, to require ABAs on motor vehicles equipped

with hydraulic brake systems. The NHTSA also amended FMVSS No. 121, Air

Brake Systems, to require ABAs on all air-braked motor vehicles and

adjustment indicators on air-braked vehicles with external adjustment

mechanisms. The effective dates are October 20, 1993, for the

amendments to FMVSS No. 105 and October 20, 1994, for the amendments to

FMVSS No. 121.

While the NHTSA rulemaking requires manufacturers to equip new

vehicles with ABAs in order to ensure brakes are in proper adjustment,

it does not affect the readjustment limits used by the States in

roadside inspections nor those required by the FHWA for periodic

inspections (contained in Appendix G to the FMCSRs, ``Minimum Periodic

Inspection Standards''). The reach of the NHTSA's regulatory authority

extends only to vehicle manufacturers. The FMCSRs apply to employers,

employees, and commercial motor vehicles which transport property or

passengers in interstate commerce.

E. Brake Adjustment Criteria

The North American Uniform Driver-Vehicle Inspection Procedure

(NAUDVIP) provides a standardized procedure used by States and local

governments to inspect in-service CMVs. The NAUDVIP was developed by

the Commercial Vehicle Safety Alliance (CVSA). The Commercial Vehicle

Safety Alliance is an association of Federal, State, and Provincial

officials responsible for the administration and enforcement of motor

carrier safety laws in the United States, Canada, and Mexico, who work

together to enhance commercial motor vehicle safety.

As a part of the NAUDVIP, the CVSA specifies certain limits for

pushrod travel. These limits, which are identical to the limits

contained in Appendix G to the FMCSRs, ``Minimum Periodic Inspection

Standards,'' have been set in consultation with motor carrier safety

enforcement officials and brake manufacturers. Brakes at or beyond

these limits are considered to be out of adjustment.

The origin of the CVSA out-of-adjustment criteria can be traced

back to the California Highway Patrol (CHP) inspection criteria

established in the 1960's. The CHP readjustment limits were based on

brake adjustment limits developed by the former Motor Vehicle

Manufacturers Association (now the American Automobile Manufacturers

Association, which no longer deals with heavy truck issues). These

limits are approximately 80 percent of full brake chamber stroke. This

is generally the point on the force versus stroke curve for a typical

brake chamber where the brake force starts decreasing rapidly with

increasing stroke.

CVSA criteria regarding brake adjustment limits specify that a

vehicle is to be placed out of service if 20 percent or more of its

brakes are defective. A brake is considered defective if its adjustment

is 1/4 inch (6.5 mm) or more beyond the readjustment limit. Two brakes

at the readjustment limit or less than 1/4 inch beyond the readjustment

limit are also considered one defective brake. For example, on a 5-axle

combination vehicle with 10 brakes, 4 brakes at the readjustment limit

would be considered as 2 defective brakes, and would also result in an

out-of-service condition.

Since the readjustment limits are based upon the characteristics of

the brake chamber, the use of ABAs would not affect the brake chamber

output force. Therefore, the FHWA believes that the current

readjustment limits are appropriate for CMVs equipped with ABAs, as

well as those currently equipped with MBAs. When properly installed and

maintained, ABAs can thus help prevent sudden and unexpected loss of

braking ability due to a loss of brake force resulting from excessive

pushrod stroke.

F. ABA Installation and Reliability

As noted in the NHTSA's final rule, ABAs are currently being

installed on a large percentage of newly-manufactured medium- and

heavy-duty air-braked vehicles. Some fleets have been specifying ABAs

for their vehicles for a number of years. However, NHTSA also noted

that one major manufacturer and several smaller ones did not provide

ABAs as standard equipment, and many purchasers did not order them as

optional equipment. In addition, the majority of CMVs currently in

operation are not equipped with ABAs.

Brake adjuster lifespan generally depends upon the number of brake

applications and the number of brake service cycles of the CMV. The

NHTSA fleet study noted that most ABAs observed performed for the

duration of the study without mechanical failure. The researchers did

observe some mechanical failures, and some apparent failures that were

actually due to other problems in the brake system, such as wear in the

foundation brakes. A number of the failures were caused by wear to

specific parts. The manufacturers reported that they have implemented

design changes to remedy those problems. The NHTSA's supplemental fleet

data collected in 1988-1990 on newer ABAs indicated high levels of

reliability. The reported average replacement rates for ABAs were 0.06

replacements per million tractor miles and 0.3 per million trailer

miles.

The NHTSA research report emphasized that ABAs must be installed in

accordance with manufacturer specifications to maintain efficient

adjustments. In most cases, no special adjustments in brake component

geometry are required. Manufacturers of these devices provide drawings,

templates, and similar aids to facilitate installation.

The figures for CMVs placed out of service appear to indicate that

there are considerable difficulties in monitoring brake adjustment

status. The findings of the NHTSA research demonstrate that BAIs,

especially when used in concert with ABAs, can make a significant

contribution to resolving the brake adjustment problem. Aside from the

clear safety benefits of maintaining proper brake adjustment, ABAs can

have a positive benefit on motor carrier productivity by preventing

CMVs from being placed out of service, reducing roadside service calls

and the resulting delays to transportation operations.

A BAI conforming to the NHTSA requirements (49 CFR 571.121) can

significantly reduce the time needed to assess brake adjustment status.

As their name implies, BAIs provide a visible indication of pushrod

stroke. There are several varieties: some BAIs consist of color-coded

or scribed marks on the pushrod, others raise a plastic or metal

``flag'' when the pushrod stroke reaches the prescribed adjustment

limit.

ABAs do not eliminate the need for periodic inspection and

maintenance of the brake system, but they do reduce the need for brake

adjustment. Recommended Practice RP-609 of The Maintenance Council of

the American Trucking Associations states that ``[a]n automatic slack

adjuster should not have to be manually adjusted except for initial

installation and at brake reline * * *.'' If adjustment is needed, it

could be a sign that the ABA is not working or that there is a problem

with the [foundation] brake system. Brake actuator strokes must still

be monitored, of course.

Like their manual counterparts, ABAs and BAIs require regular

maintenance. They operate in the same hostile and exposed environment

as manual systems. The NHTSA notes that their performance is affected

by failures and wear in other parts of the foundation brake system,

and, like other components, their life expectancy can be less than that

of the tractor or trailer on which they are installed.

Discussion of Proposal

The FHWA believes that the information presented in the reports

cited above indicates that both motor carriers and the travelling

public may derive substantial operational and safety benefits from the

use of automatic brake adjusters and brake adjustment indicators.

The FHWA proposes to amend the FMCSRs by adding a new Sec. 393.53,

Automatic Brake Adjusters and Brake Adjustment Indicators. This section

would be added to Subpart C, Brakes.

The provisions of paragraphs (a), (b), and (c) would require that

automatic brake adjusters and brake adjustment indicators installed on

newly manufactured CMVs to comply with the requirements of FMVSS 105

and 121 be maintained by the motor carriers operating those CMVs.

Questions

The FHWA believes there are also opportunities for improvements to

operational safety of CMVs manufactured prior to the effective dates of

the recent amendments to FMVSS 105 and 121. The FHWA therefore requests

information regarding the potential impacts of requiring CMVs subject

to the FMCSRs to be retrofitted with ABAs, and for requiring air-braked

CMVs with external adjustment mechanisms to be retrofitted with brake

adjustment indicators. The FHWA specifically requests comments on the

following questions:

1. Should air-braked CMVs manufactured before the effective date of

NHTSA's rule be required to be retrofitted with ABAs?

2. Should all air-braked CMVs with external brake adjustment

mechanisms be required to be retrofitted with brake adjustment

indicators?

3. If certain CMVs are to be retrofitted, how much time should be

allowed for installation of the new equipment?

4. Are there certain types or configurations of air-braked vehicles

that cannot be equipped with ABAs because of space limitations around

the axles and wheels?

5. Should different periods be specified for retrofitting single-

unit trucks, tractors, converter dollies, and trailers?

6. The requirements proposed by this NPRM would exclude air-braked

vehicles that were not subject to FMVSS No. 121 on the date of

manufacture. (Vehicles not subject to the requirements are listed under

Paragraph S3 of Sec. 571.121, and include certain types of limited- or

specialized-use vehicles such as wide trailers, vehicles equipped with

an axle with a gross axle weight rating of 29,000 pounds or more, any

truck or bus that has a speed attainable in 2 miles of not more than 33

mph, heavy hauler trailer sets, and load divider dollies.) Should

specific types of CMVs, or CMVs used in unique operations, (i.e., CMVs

that are not subject to the requirements of FMVSS 121, but are subject

to the FMCSRs) be exempt from a requirement to be retrofitted with

ABAs? Should these specific types of air-braked CMVs manufactured on or

after October 20, 1994, be required to be equipped with ABAs prior to

being placed in operation in interstate commerce? Please provide

details.

7. What are the costs associated with retrofitting an ABA compared

to replacement of an MBA? Please include the cost of the device, the

time required to complete the installation, and a representative hourly

salary of the mechanic performing the installation. Please also include

a ``loss of use'' cost figure if a CMV were to be taken out of revenue

service for retrofitting at some time other than a time when a brake

adjuster would normally be due for replacement. How often do tractors

and trailers visit a facility where retrofitting could take place?

8. Should the FHWA consider a retrofitting requirement for

hydraulically-braked CMVs? Please address the cost questions asked in

Question 7.

The FHWA requests that commenters address the specific questions

above. However, the FHWA encourages commenters to include a discussion

of any other issues that the commenters believe are relevant to the use

and/or retrofitting of automatic brake adjusters and brake adjustment

indicators on CMVs.

Rulemaking Analyses and Notices

All comments received before the close of business on the comment

closing date indicated above will be considered and will be available

for examination in the docket at the above address. Comments received

after the comment closing date will be filed in the public docket and

will be considered to the extent practicable. In addition to late

comments, the FHWA will also continue to file, in the public docket,

relevant information that becomes available after the comment closing

date. Interested persons should continue to examine the public docket

for new material.

Executive Order 12866 (Regulatory Planning and Review) and DOT

Regulatory Policies and Procedures

The FHWA 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 would, if adopted,

provide a companion operational standard for brakes in the FMCSRs to

make them consistent with the manufacturing standards in the FMVSSs 105

and 121. It would require automatic brake adjusters and brake

adjustment indicators installed on newly manufactured CMVs in

accordance with those manufacturing standards to be maintained by the

motor carriers operating those vehicles. Based on the NHTSA studies,

the FHWA believes that operation and maintenance costs of the automatic

brake adjusters and adjustment indicators required under the new FMVSSs

will be lower than costs of the devices previously required. Although

the FHWA requests information concerning the possibility of requiring

these devices to be retrofitted to CMVs placed in operation prior to

the effective dates of FMVSSs 105 and 121, no rule to require such

retrofitting is being proposed at this time. It is anticipated that the

economic impact of this rulemaking will be minimal; therefore, a full

regulatory evaluation is not required. If the FHWA proposes

retrofitting of these devices at some future date, a regulatory

evaluation of the effects of that action will be prepared at that time.

Regulatory Flexibility Act

In compliance with the Regulatory Flexibility Act (5 U.S.C. 601-

612), the FHWA has evaluated the effects of this proposed rule on small

entities. This rule would modify the operational standards for brakes

in the Federal Motor Carrier Safety Regulations (FMCSRs) to make them

consistent with the manufacturing standards in the Federal Motor

Vehicle Safety Standards (FMVSSs) numbers 105 and 121, which now

require the installation of automatic brake adjusters and adjustment

indicators on certain newly-manufactured CMVs. As stated above, the

FHWA believes that operation and maintenance costs of the automatic

brake adjusters and adjustment indicators required under the new FMVSSs

will be lower than costs of the devices previously required. Therefore,

the FHWA hereby certifies that this action would not have a significant

economic impact on a substantial number of small entities.

Executive Order 12612 (Federalism Assessment)

This action has been analyzed in accordance with the principles and

criteria contained in Executive Order 12612, and it has been determined

that this action does not have sufficient federalism implications to

warrant the preparation of a federalism assessment.

Paperwork Reduction Act

This action does not contain a collection of information

requirement for purposes of the Paperwork Reduction Act of 1980, 44

U.S.C. 3501 et seq.

National Environmental Policy Act

The agency has analyzed this action for the purpose of the National

Environmental Policy Act of 1969 (42 U.S.C. 4321 et seq.) and has

determined that this action would not have any effect on the quality of

the environment.

Executive Order 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 apply to this program.

Regulation Identification Number

A regulation identification number (RIN) is assigned to each

regulatory action listed in the Unified Agenda of Federal Regulations.

The Regulatory Information Service Center publishes the Unified Agenda

in April and October of each year. The RIN in the heading of this

document can be used to cross reference this action with the Unified

Agenda.

List of Subjects in 49 CFR Part 393

Freight Transportation, Highway safety, Highways and roads, Motor

carriers, and Motor vehicle safety.

In consideration of the foregoing, the FHWA is proposing to amend

title 49, Code of Federal Regulations, part 393, as follows:

PART 393--[AMENDED]

1. The authority citation for part 393 continues to read as

follows:

Authority: Section 1041(b) of Pub. L. 102-240, 105 Stat. 1914,

1993 (1991); 49 U.S.C. 3102; 49 U.S.C. app. 2505; 49 CFR 1.48.

2. In Subpart C, Sec. 393.53 is added to read as follows:

Sec. 393.53 Automatic brake adjusters and brake adjustment indicators.

(a) Automatic brake adjusters (hydraulic brake systems). Each

commercial motor vehicle manufactured on or after October 20, 1993, and

equipped with a hydraulic brake system, shall be equipped with an

automatic brake adjustment system that meets the requirements of

Federal Motor Vehicle Safety Standard No. 105 (49 CFR 571.105, S5.1) of

this title) applicable to the vehicle at the time it was manufactured.

(b) Automatic brake adjusters (air brake systems). Each commercial

motor vehicle manufactured on or after October 20, 1994, and equipped

with an air brake system, shall be equipped with an automatic brake

adjustment system that meets the requirements of Federal Motor Vehicle

Safety Standard No. 121 (49 CFR 571.121, S.5.1.8) applicable to the

vehicle at the time it was manufactured.

(c) Brake adjustment indicator (air brake systems). On each

commercial motor vehicle manufactured on or after October 20, 1994, and

equipped with an air brake system which contains an external automatic

adjustment mechanism and an exposed pushrod, the condition of service

brake under-adjustment shall be displayed by a brake adjustment

indicator conforming to the requirements of Federal Motor Vehicle

Safety Standard No. 121 (49 CFR 571.121, S5.1.8) applicable to the

vehicle at the time it was manufactured.

Issued on: July 28, 1994.

Rodney E. Slater,

Federal Highway Administrator.

[FR Doc. 94-18901 Filed 8-2-94; 8:45 am]

BILLING CODE 4910-22-P