Interpretation ID: nht76-4.31

DATE: 10/29/76

FROM: AUTHOR UNAVAILABLE; F. Berndt; NHTSA

TO: Truck Body and Equipment Association, Inc.

TITLE: FMVSS INTERPRETATION

TEXT: This responds to the Truck Body and Equipment Association's letter of September 14, 1976, inquiring as to the effect of Standard No. 121, Air Brake Systems, on State laws relating to air brake performance. You ask whether the Commonwealth of Massachusetts can impose requirements pertaining to parking brake release on trucks and buses which differ from provisions contained in the Federal standard.

I believe that the question you raised is identical to a question raised by the State of California, International Harvester Company, and White Motor Corporation in October 1974, prior to the effective dates of Standard No. 121. It was our opinion at that time that promulgation by a State of a more restrictive parking brake requirement providing for the installation of a release not specified in Standard No. 121 was prohibited by @ 103(d) of the National Traffic and Motor Vehicle Safety Act. A copy of that letter is enclosed for your information.

SINCERELY,

TRUCK BODY AND EQUIPMENT ASSOCIATION, INC.

September 14, 1976

Frank A. Berndt Office of Chief Counsel National Highway Traffic Safety Administration

The state of Massachusetts has established a law requiring an air brake equipped truck sold in that state, to have a system that differs from those presently designed and developed for FMVSS 121 compliance. The difference lies in the Massachusetts requirement that the air brake system be equipped with an additional air reservoir or "third tank" capable of supplying air to the spring set parking brakes in case of an air brake failure. (See Attachment # I).

At the present time, all new trucks equipped with air brakes are required by Department of Transportation through National Highway Traffic Safety Administration to be completed in accordance with the performance levels found in FMVSS 121. As a result, all new trucks have air systems that are capable of meeting the application and release times, system build up times and the spring brake modulation requirements found in FMVSS 121.

The Massachusetts law was instituted to provide an additional means by which the spring brakes may be released during emergency situations. This release requirement is already supplied on all new chassis produced today in compliance with FMVSS 121 by a mechanical means.

The Massachusetts law requires that the existing 121 system be repiped to accommodate the new third tank and emergency release circuit. Any modification to the complex 121 system increases the likelihood of system damage or the modification may cross connect the split air system thus defeating the intent of two separate brake systems.

The chances of a modified system failure seems more likely than a FMVSS 121 brake lock up on a railroad grade crossing.

In previous correspondence the National Highway Traffic Safety Administration Office of Chief Counsel, has indicated that a state can not set any motor vehicle safety standard that is in variance with an existing Federal Motor Vehicle Safety Standard. (See Attachment # II).

We at the Truck Body and Equipment Association feel that the Massachusetts requirement for a modified brake system is inconsistent with the requirements outlined in FMVSS 121 and would appreciate the National Highway Traffic Safety Administration's opinion of the legality of this state regulation.

Byron A. Crampton Manager of Engineering Services

ATTACHMENTS

The Commonwealth of Massachusetts Registry of Motor Vehicles

August 13, 1976

Dear Sir:

In reply to your inquiry as to brake requirements on commercial vehicle chassis, I am enclosing a copy of that portion of Massachusetts law in regards to brakes.

If a vehicle is equipped with air brakes and the parking or emergency brake portion of the brake system is a spring loaded brake, Massachusetts requires a third air tank and there must be a check valve between your main source (wet/dry tank or tanks) of supply and the third tank.

Under emergency conditions when there is a loss of the service brake, the spring loaded brake is automatically applied. To move the vehicle would require the winding down to release the spring loaded brake. Our requirement of a third tank allows 4 to 6 quick release operations so that the vehicle can be safely moved out of traffic, a roadway, a railroad crossing or an intersection.

Any vehicle equipped with air brakes and a spring loaded parking/emergency brake must be equipped with the third tank for registration and operation in Massachusetts. If we find a vehicle is not so equipped (third tank) we will not permit it to be registered. If it has been registered, statutory law allows the Registrar of Motor Vehicles to suspend the registration. No consideration is given relative to the reinstatement of the suspended registration until the brake system is in compliance and examined by an inspector from this department.

I hope this information will be of some help to you.

Charles V. Mulhern Supervisor Vehicle Inspection Branch

provisions of this section shall be punished by a fine of not less than ten nor more than one hundred dollars.

@ 7. Brakes, Lights and Other Equipment

[MASSACHUSETTS REGULATION OMITTED]

March 21, 1975

Chief Counsel NATIONAL HIGHWAY TRAFFIC SAFETY ADMINISTRATION

Recently several members of the Truck Body and Equipment Association have raised questions concerning state versus federal motor vehicle lighting requirements.

The vehicle in question is a multipurpose passenger vehicle less than eighty (80) inches wide, equipped with a raised roof.

Our question is as follow: Can a state require a motor vehicle to be equipped with lights not required under FMVSS #1007

Thanking you in advance for your help, I am,

Byron Crampton Manager of Engineering Services