[Federal Register Volume 61, Number 33 (Friday, February 16, 1996)]
[Rules and Regulations]
[Pages 6173-6175]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 96-3258]



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DEPARTMENT OF TRANSPORTATION

National Highway Traffic Safety Administration

49 CFR Part 571

[Docket No. 90-3; Notice 6]
RIN 2127-AF63


Federal Motor Vehicle Safety Standards; Air Brake Systems; Air 
Compressor Cut-In

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

ACTION: Final rule.

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SUMMARY: This document concludes a rulemaking proceeding begun in 
response to a petition for rulemaking submitted by the Truck Trailer 
Manufacturers Association (TTMA). It amends Standard No. 121, Air Brake 
Systems, to require the automatic activation of the air compressor on a 
powered vehicle whenever the pressure in the air brake system drops 
below 100 pounds per square inch (psi). The agency has concluded that 
the amendment will ensure that new truck tractors provide trailers with 
sufficient air pressure for release of the trailer parking brakes and 
provide adequate service braking. In addition, the amendment will 
provide greater air reserves on all air braked vehicles.

DATES: Effective date. The amendment becomes effective March 18, 1996. 
Compliance date. Compliance with the amendment will be required on and 
after March 1, 1997.
    Petitions for reconsideration. Any petitions for reconsideration of 
this rule must be received by NHTSA no later than April 1, 1996.

ADDRESSES: Petitions for reconsideration of this rule should refer to 
the above referenced docket numbers and should be submitted to: 
Administrator, National Highway Traffic Safety Administration, 400 
Seventh Street SW., Washington, D.C. 20590.

FOR FURTHER INFORMATION CONTACT:

    For non-legal issues: Mr. Richard Carter, Office of Crash 
Avoidance, National Highway Traffic Safety Administration, 400 Seventh 
Street, SW., Washington, D.C. 20590 (202) 366-5274.
    For legal issues: Mr. Marvin L. Shaw, NCC-20, Rulemaking Division, 
Office of Chief Counsel, National Highway Traffic Safety 
Administration, 400 Seventh Street, SW., Washington, D.C. 20590 (202-
366-2992).

SUPPLEMENTARY INFORMATION:

I. Background

    Standard No. 121, Air Brake Systems, specifies performance and 
equipment requirements for braking systems on vehicles equipped with 
air brakes, including a requirement specifying the minimum air pressure 
at which a towing vehicle's air compressor governor must automatically 
activate the compressor. The governor maintains reservoir air pressure 
between predetermined minimum and maximum pressures. Under the current 
requirement in S5.1.1.1, the governor must automatically activate the 
air compressor when air pressure in the reservoir falls to 85 pounds 
per square inch (psi). Currently manufactured air brake systems 
typically operate between 100 psi and 120 psi.
    NHTSA adopted the air compressor governor minimum cut-in 
requirement on October 8, 1991. (56 FR 50666) In adopting the 
requirement, the agency explained that the requirement will ensure, in 
the event of an air leak in a tractor's brake supply system, the air 
compressor for the system will be activated to restore or maintain 
pressure in the system until the air leak is detected and corrected. 
The agency further stated that since most vehicles already complied 
with the cut-in requirement, it would not result in an undue burden for 
manufacturers.
    The October 1991 final rule also amended Standard No. 121 by 
deleting the requirement for each trailer to have a separate protected 
reservoir for the purpose of releasing the parking brake. Under the 
rule, air pressure from the tractor supply lines may be used to 

[[Page 6174]]
release the trailer parking brakes instead of air from a separate 
reservoir. The final rule also specified requirements for a minimum air 
pressure of 70 psi in the trailer's supply line in the event of 
pneumatic failure. The final rule also prevents the automatic 
application of the trailer parking brakes while the minimum trailer 
supply line air pressure is maintained.

II. Rulemaking Petition

    On August 2, 1994, the Truck Trailer Manufacturers Association 
(TTMA) submitted a petition for rulemaking to amend S5.1.1.1 of 
Standard No. 121 to increase the minimum air pressure, at which the 
governor is required to activate the air compressor, from 85 psi to 100 
psi. The petitioner stated that its requested amendment is necessary to 
assure that new truck tractors provide air braked trailers with 
sufficient pressure for release of the trailer parking brakes and to 
provide adequate service braking. TTMA said that the current 85 psi air 
pressure compressor cut-in requirement may not be sufficient to ensure 
that adequate pressure is supplied to a trailer being towed by a 
tractor. TTMA also stated that higher truck or tractor air pressures 
increase the speed at which trucks or tractors can resupply trailers 
with air and that these higher pressures will store more air for use by 
the braking systems. The petitioner further stated that ``all tractor 
manufacturers are now building tractors whose nominal compressor cut-in 
pressure is at least 100 psi.''

III. NHTSA Proposal

    On June 13, 1995, NHTSA published a notice of proposed rulemaking 
(NPRM) proposing to increase the required minimum air compressor cut-in 
pressure from 85 psi to 100 psi. (60 FR 31135) The agency set forth the 
following reasons for its decision to propose increasing the cut-in air 
pressure above the current 85 psi level. First, the agency believed 
that the proposed amendment would enhance safety by better ensuring 
that new truck tractors are capable of providing trailers with 
sufficient pressure for release of the trailer parking brakes and 
provide adequate service braking. Specifically, raising the minimum 
cut-in pressure would allow the storage of an additional volume of 
compressed air that would be available for an air brake system. Second, 
the agency stated that the proposal to maintain an overall higher 
system air pressure would allow a better ``match up'' of protection 
valve settings between the tractors and trailers. Third, the agency 
stated that a greater margin of safety would be provided for long 
stroke brake chambers, which need more compressed air.
    After explaining its tentative conclusion that increasing the cut-
in pressure to 100 psi would not result in any safety problems, NHTSA 
invited comments about whether the proposed amendment would affect 
safety.
    NHTSA further stated that its analysis of current manufacturing 
practices confirmed TTMA's statement that manufacturers are typically 
building vehicles with a cut-in pressure of at least 100 psi. The 
docket includes a memorandum summarizing the agency's discussions with 
vehicle manufacturers and the American Trucking Associations (ATA) in 
which they indicate that new truck tractors are typically equipped with 
governors that activate the air compressor when air pressure drops to 
100 psi. In addition, Midland-Grau and Allied Signal, which together 
produce over 95 percent of the air compressors and governors in the 
United States, stated that they set their air compressors and governors 
at 100 psi or higher. Based on its research, NHTSA was aware of no 
company that manufactures these devices with a cut-in pressure between 
85 and 100 psi nor of any purchaser that requests a cut-in pressure in 
this lower range. Accordingly, NHTSA believed that the proposed 
amendment would codify existing industry practice, since equipment on 
new vehicles are being built with the proposed settings.

IV. Comments on the NPRM and Final Rule

    NHTSA received comments from ATA, the Truck Manufacturing 
Association (TMA), the Heavy Duty Brake Manufacturing Council (HDBMC), 
the Truck Trailer Manufacturers Association (TTMA), the Advocates for 
Highway Safety (Advocates), vehicle manufacturers (Ford, Mack Truck, 
Navistar, and PACCAR), brake manufacturers (Allied Signal and Midland-
Grau), and an engineering consultant.
    The commenters generally supported the proposal to raise the air 
compressor cut-in pressure to 100 psi or more. Even though it did not 
oppose the proposal, TMA stated that there was little need for adopting 
the proposal since the vast majority of vehicles already meet the 
proposed requirements and the rest will soon comply. That organization 
expressed concern that while most domestic manufacturers already comply 
with the cut-in requirements, new entries and imports may be designed 
to the 85 psi requirement. However, NHTSA believes that in Europe, cut-
in pressure is typically over 100 psi. Should TMA have specific data on 
this issue, it is encouraged to present it to the agency. TMA, 
Navistar, AlliedSignal, Mack Trucks, and HDBMC requested that the 
agency modify the wording to state that the cut-in pressure shall be 
``100 psi or greater.'' These commenters believed that this modified 
wording will accommodate variations in manufacturers' recommended cut-
in pressures.
    Based on its review of the comments and the available information, 
NHTSA has decided to amend Standard No. 121 to require the automatic 
activation of the air compressor whenever the pressure in the air brake 
system drops below 100 psi. As the agency stated in the NPRM, this 
amendment will ensure that new truck tractors are capable of providing 
trailers with sufficient pressure for release of the trailer parking 
brakes and provide adequate service braking. Specifically, raising the 
cut-in pressure allows the storage of an additional volume of 
compressed air that will be available for an air brake system. Second, 
requiring an overall higher system air pressure will allow a better 
``match up'' of protection valve settings between the tractors and 
trailers. Third, the amendment will provide a greater margin of safety 
for long stroke brake chambers, which need more compressed air. The 
agency anticipates no safety problems as the result of this amendment.
    ATA commented that it had no objection to the proposal if it 
applied only to towing trucks and tractors. However, that organization 
opposed applying the proposal to single unit vehicles.
    NHTSA has decided to apply the air compressor cut-in pressure 
requirements to all powered vehicles, including single unit vehicles. 
The agency believes that raising the air compressor cut-in pressure to 
100 psi provides potential safety benefits in addition to providing 
faster brake release times between the tractor and trailers and better 
balancing of pressures. The agency has decided to include single unit 
vehicles in the requirements because of its concern over increased air 
consumption with long stroke brake chambers combined with ABS. The 
agency is currently reviewing petitions for reconsideration on its rule 
allowing long stroke brake chambers and, subsequent to its response, 
encourages ATA and others to reexamine this issue. Even though ATA 
stated that it was concerned that there may be some special 
applications or vehicle types where a lower air pressure is desirable 
or necessary, the agency is not aware of any specific examples of 

[[Page 6175]]
any such special conditions that preclude the use of the higher air 
pressure.
    In the NPRM, NHTSA proposed that compliance date for the final rule 
be 30 days after its publication in the Federal Register. The agency 
stated that this amendment would have no adverse effect on 
manufacturers since all manufacturers currently comply with the 
proposed requirements. NHTSA requested comments about whether a 
leadtime of 30 days would be appropriate or whether more lead time was 
necessary.
    Advocates favored a compliance date of 30 days after the notice's 
publication. Mack requested that the compliance date not occur before 
March 1, 1996, since that company manufactures two low volume truck 
tractor models and a high volume truck model that require a longer 
leadtime to convert to the higher cut-in pressure. PACCAR, commenting 
through TMA, stated that it will need 12 months to adapt to the 
proposed change.
    NHTSA has decided to set a compliance date of March 1, l997 for the 
amended air compressor cut-in pressure. The agency believes that 
providing additional leadtime is necessary given that some 
manufacturers will need additional time to modify certain vehicles. 
Given that these manufacturers would have to make significant changes 
to certain air brake systems, they would not be able to make the 
modifications within the 30 day period that was initially proposed. 
This compliance date also corresponds to that for the antilock brake 
system and stopping distance requirements for truck tractors.

V. Rulemaking Analyses and Notices

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

    This rulemaking was not reviewed under E.O. 12866. NHTSA has 
analyzed this rulemaking 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 will have a minimal effect on the costs or performance 
of the existing air brake systems. For most manufacturers and most 
vehicles, today's amendment merely codifies an existing industry 
practice.

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 amendment will not have a significant 
economic impact on a substantial number of small entities. Vehicle and 
brake manufacturers typically do not qualify as small entities. Vehicle 
manufacturers, small businesses, small organizations, and small 
governmental units which purchase motor vehicles will not be 
significantly affected by the requirements since the cost of new 
vehicles will not change. 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 rule will not have sufficient Federalism implications to 
warrant preparation of a Federalism Assessment. No State laws will be 
affected.

4. National Environmental Policy Act

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

5. Civil Justice Reform

    This rule will not have any retroactive effect. Under section 
103(d) of the National Traffic and Motor Vehicle Safety Act (49 U.S.C. 
30111), whenever a Federal motor vehicle safety standard is in effect, 
a state may not adopt or maintain a safety standard applicable to the 
same aspect of performance which is not identical to the Federal 
standard. Section 105 of the Act (49 U.S.C. 30161) sets forth a 
procedure for judicial review of final rules establishing, amending or 
revoking Federal motor vehicle safety standards. That section does not 
require submission of a petition for reconsideration or other 
administrative proceedings before parties may file suit in court.

List of Subjects in 49 CFR Part 571

    Imports, Motor vehicle safety, Motor vehicles, Reporting and 
recordkeeping requirements, Rubber and rubber products, Tires.
    In consideration of the foregoing, the agency is amending part 571 
of Title 49 of the Code of Federal Regulations as follows:

PART 571--[AMENDED]

    1. The authority citation for Part 571 continues to read as 
follows:

    Authority: 49 U.S.C. 322, 30111, 30115, 30117, and 30166; 
delegation of authority at 49 CFR 1.50.

    2. In Sec. 571.121, S5.1.1.1 is revised to read as follows:


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

* * * * *
    S5.1.1.1 Air compressor cut-in pressure. The air compressor 
governor cut-in pressure shall be 100 p.s.i. or greater.
* * * * *
    Issued on: February 8, 1996.
Ricardo Martinez,
Administrator.
[FR Doc. 96-3258 Filed 2-15-96; 8:45 am]
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