94-18901. Parts and Accessories Necessary For Safe Operation; Automatic Brake Adjusters and Brake Adjustment Indicators  

  • [Federal Register Volume 59, Number 148 (Wednesday, August 3, 1994)]
    [Unknown Section]
    [Page 0]
    From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
    [FR Doc No: 94-18901]
    
    
    [[Page Unknown]]
    
    [Federal Register: August 3, 1994]
    
    
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    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).
    
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    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
    
    
    

Document Information

Published:
08/03/1994
Department:
Federal Highway Administration
Entry Type:
Uncategorized Document
Action:
Notice of proposed rulemaking (NPRM).
Document Number:
94-18901
Dates:
Comments must be received on or before October 3, 1994.
Pages:
0-0 (1 pages)
Docket Numbers:
Federal Register: August 3, 1994, FHWA Docket No. MC-94-9
RINs:
2125-AD37
CFR: (1)
49 CFR 393.53