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

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

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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

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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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