Parts and Accessories Necessary For Safe Operation; Automatic Brake Adjusters and Brake Adjustment Indicators
Topics: Federal Highway Administration
Rodney E. Slater
August 3, 1994
[Federal Register: August 3, 1994] ----------------------------------------------------------------------- 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
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