[Federal Register Volume 59, Number 131 (Monday, July 11, 1994)]
[Unknown Section]
[Page 0]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 94-16613]


[[Page Unknown]]

[Federal Register: July 11, 1994]


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DEPARTMENT OF TRANSPORTATION

National Highway Traffic Safety Administration

49 CFR Part 571

[Docket No. 94-56; Notice 1]
RIN 2127-AF01

 

Federal Motor Vehicle Safety Standards; Air Over Hydraulic Brake 
Systems

AGENCY: National Highway Traffic Safety Administration (NHTSA), 
Department of Transportation.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: This notice responds to a petition submitted by John Kourik. 
The notice proposes to amend the requirements in Standard No. 121, Air 
Brake Systems, to include a definition of air-over-hydraulic brake 
subsystems. The agency believes that this proposed definition would 
clarify the classification of vehicles equipped with these subsystems 
and thus eliminate the need for manufacturers to request, and the 
agency to respond to, interpretations about them.

DATES: Comments. Comments must be received on or before September 9, 
1994.
    Proposed Effective Date. The proposed amendments in this notice 
would become effective 30 days after publication of a final rule in the 
Federal Register.

ADDRESSES: Comments should refer to the docket and notice numbers above 
and be submitted to: Docket Section, National Highway Traffic Safety 
Administration, 400 Seventh Street, SW., Washington, DC 20590. Docket 
hours are 9:30 a.m. to 4 p.m., Monday through Friday.

FOR FURTHER INFORMATION CONTACT:
Mr. Chris Tinto, Office of Vehicle Safety Standards, National Highway 
Traffic Safety Administration, 400 Seventh Street, SW., Washington, DC 
20590 (202-366-5229).

SUPPLEMENTARY INFORMATION:

Background

    Air-over-hydraulic brake systems typically consist of an air brake 
system from the treadle valve to an air brake chamber that provides the 
mechanical force to actuate a hydraulic-operated master cylinder. In 
turn, the hydraulic master cylinder actuates the brake shoes or pads. 
The air brake chamber unit combined with the hydraulic-operated master 
cylinder is called the ``power cluster'' and generally serves as the 
separating point between the air- and hydraulic-actuated portions of 
the air-over-hydraulic brake system.
    Air-over-hydraulic brake systems are installed on about one percent 
of medium and heavy trucks sold in the United States. This percentage 
represents about 2,000 vehicles, most of which are Class 6 vehicles 
with gross vehicle weight ratings (GVWRs) between 19,501 and 26,000 
pounds.
    Federal motor vehicle safety standard No. 121, Air brake systems, 
currently defines ``air brake system'' to mean

a system that uses air as a medium for transmitting pressure or 
force from the driver control to the service brake, but does not 
include a system that uses compressed air or vacuum only to assist 
the driver in applying muscular force to hydraulic or mechanical 
components. (49 CFR Sec. 571.121)

Part 570, Vehicle In Use Inspection Standards, defines ``Air-over-
hydraulic brake system'' to mean

a subsystem of the air brake that uses compressed air to transmit a 
force from the driver control to a hydraulic brake system to actuate 
the service brakes. (49 CFR Part 570, emphasis added)

The italic portion of the definition of air-over-hydraulic subsystem 
explicitly states that an air-over-hydraulic brake subsystem means a 
subsystem of the air brake system.
    In initially issuing Standard No. 121, NHTSA stated that ``it 
should be noted that the term `air brake system' as defined in the 
standard applies to the brake configuration commonly referred to as 
`air-over-hydraulic,' in which failure of either medium can result in 
complete loss of braking ability.'' (36 FR 3817, February 27, 1971). 
The agency reiterated its position that an air-over-hydraulic brake 
system is subject to Standard No. 121, stating that ``Standard No. 105a 
[Hydraulic Brake Systems] does not apply to vehicles equipped with 
`air-over-hydraulic' systems, which remain within the purview of 
Standard No. 121* * *.'' (37 FR 17970, September 2, 1972.) Moreover, 
NHTSA has issued several interpretations stating that a vehicle 
equipped with an air-over-hydraulic brake system must comply with the 
requirements in Standard No. 121.
    NHTSA received a petition from Mr. John Kourik, requesting that the 
agency amend Standard No. 121 to specify that an air-over-hydraulic 
brake subsystem is subject to that Standard. The petitioner stated that 
such an amendment would avoid the need for manufacturers to request 
interpretations about air-over-hydraulic brake systems.
    After reviewing the petition, NHTSA has decided to propose amending 
Standard No. 121 by expanding the current definition of air brake 
system to incorporate the definition of air-over-hydraulic brake 
subsystem. The agency notes that even though the definition of an air 
brake system currently includes a description of an air-over-hydraulic 
subsystem, it is not explicitly clear on the face of the standard that 
such a subsystem is classified as an air-braked system and that a 
vehicle equipped with such a subsystem would thus have to comply with 
the requirements in Standard No. 121. NHTSA believes that it would be 
appropriate to clarify the classification of air-over-hydraulic brake 
systems. By amending the definition of an air brake system to state 
explicitly that an air-over-hydraulic brake subsystem is classified as 
an air brake system, the agency would eliminate the need felt by some 
manufacturers to request interpretations regarding the standard's 
applicability to vehicles equipped with air-over-hydraulic brake 
subsystems.

Rulemaking Analyses and Notices

1. Executive Order 12866 (Federal Regulation Planning and Review) and 
DOT Regulatory Policies and Procedures

    This proposal was not reviewed under E.O. 12866. NHTSA has analyzed 
this proposal and determined that it is not ``significant'' within the 
meaning of the Department of Transportation's regulatory policies and 
procedures. A full regulatory evaluation is not required because the 
rule, if adopted, would have no mandatory effects. Instead, the 
proposal would only codify a longstanding agency interpretation. 
Therefore, this rulemaking would not have any cost impacts.

2. Regulatory Flexibility Act

    In accordance with the Regulatory Flexibility Act, NHTSA has 
evaluated the effects of this action on small entities. Based upon this 
evaluation, I certify that the proposed amendment would not have a 
significant economic impact on a substantial number of small entities. 
Vehicle and brake manufacturers typically would not qualify as small 
entities. This amendment would affect small businesses, small 
organizations, and small governmental units to the extent that these 
entities purchase vehicles. However, this amendment would have no 
significant cost impact on vehicles. For these reasons, vehicle 
manufacturers, small businesses, small organizations, and small 
governmental units which purchase motor vehicles would not be 
significantly affected by the proposed requirements. Accordingly, no 
regulatory flexibility analysis has been prepared.

3. Executive Order 12612 (Federalism)

    This action has been analyzed in accordance with the principles and 
criteria contained in Executive Order 12612, and it has been determined 
that the proposed rule would not have sufficient Federalism 
implications to warrant preparation of a Federalism Assessment. No 
State laws would be affected.

4. National Environmental Policy Act

    Finally, the agency has considered the environmental implications 
of this proposed rule in accordance with the National Environmental 
Policy Act of 1969 and determined that the proposed rule would not 
significantly affect the human environment.

Public Comments

    Interested persons are invited to submit comments on the proposal. 
It is requested but not required that 10 copies be submitted.
    All comments must not exceed 15 pages in length. (49 CFR 553.21). 
Necessary attachments may be appended to these submissions without 
regard to the 15-page limit. This limitation is intended to encourage 
commenters to detail their primary arguments in a concise fashion.
    If a commenter wishes to submit certain information under a claim 
of confidentiality, three copies of the complete submission, including 
purportedly confidential business information, should be submitted to 
the Chief Counsel, NHTSA, at the street address given above, and seven 
copies from which the purportedly confidential information has been 
deleted should be submitted to the Docket Section. A request for 
confidentiality should be accompanied by a cover letter setting forth 
the information specified in the agency's confidential business 
information regulation. 49 CFR part 512.
    All comments received before the close of business on the comment 
closing date indicated above for the proposal will be considered, and 
will be available for examination in the docket at the above address 
both before and after that date. To the extent possible, comments filed 
after the closing date will also be considered. Comments received too 
late for consideration in regard to the final rule will be considered 
as suggestions for further rulemaking action. The NHTSA will continue 
to file relevant information as it becomes available in the docket 
after the closing date, and it is recommended that interested persons 
continue to examine the docket for new material.
    Those persons desiring to be notified upon receipt of their 
comments in the rules docket should enclose a self-addressed, stamped 
postcard in the envelope with their comments. Upon receiving the 
comments, the docket supervisor will return the postcard by mail.

List of Subjects in 49 CFR Part 571

    Imports, Incorporation by reference, Motor vehicle safety, Motor 
vehicles, Rubber and rubber products, Tires.
    In consideration of the foregoing, the agency proposes to amend 
Standard No. 121, Air Brake Systems, in Title 49 of the Code of Federal 
Regulations at part 571 as follows:

PART 571--[AMENDED]

    1. The authority citation for part 571 would continue to read as 
follows:

    Authority: 15 U.S.C. 1392, 1401, 1403, 1407; delegation of 
authority at 49 CFR 1.50.

    2. In Sec. 571.121, S4 would be amended by revising the definition 
of ``Air Brake System'' and by adding the definition of ``Air-over-
hydraulic brake subsystem'' to read as follows:


Sec. 571.121  Standard No. 121; Air brake systems.

* * * * *
    S4 * * *
    Air brake system means a system, including an air-over-hydraulic 
brake subsystem, that uses air as a medium for transmitting pressure or 
force from the driver control to the service brake, but does not 
include a system that uses compressed air or vacuum only to assist the 
driver in applying muscular force to hydraulic or mechanical 
components.
* * * * *
    Air-over-hydraulic brake subsystem means a subsystem of the air 
brake that uses compressed air to transmit a force from the driver 
control to a hydraulic brake system to actuate the service brakes.

    Issued on: July 5, 1994.
Barry Felrice,
Associate Administrator for Rulemaking.
[FR Doc. 94-16613 Filed 7-8-94; 8:45 am]
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