Interpretation ID: nht79-1.12

DATE: 09/26/79

FROM: AUTHOR UNAVAILABLE; F. Berndt; NHTSA

TO: Essex Group

TITLE: FMVSS INTERPRETATION

TEXT:

Mr. Daniel I. Borovik Director of Development and Planning Essex Group Wire Assembly Division 6233 Concord Avenue Detroit, Michigan 48211

Dear Mr. Borovik:

This is in reply to your letter of August 7, 1979, asking whether "trailer warning lamps should flash or be steady-burning" when the towing vehicle's hazard warning system is actuated and the service brakes are applied.

Federal Motor Vehicle Safety Standard No. 108 does not require trailers to be equipped with hazard warning signal lamps, and you may design your trailer tow electrical package without reference to it. Lack of Federal regulation in this area, however, means that each State may set its own requirements, and you should ascertain whether such exist before finalizing your design.

Sincerely,

Frank Berndt Chief Counsel

ESSEX GROUP WIRE ASSEMBLY DIVISION 6233 Concord Ave. Detroit, Michigan 48211

August 7, 1979

Office of the Chief Counsel U.S. Department of Transportation National Highway Traffic Safety Administration 400 7th Street, S.W. Washington, D.C. 20590 Gentlemen:

Reference is made to FMVSS 108, paragraphs 4.1.1.32, 4.5.4 and 4.6.

We are developing a trailer tow electrical package for passenger cars and light trucks. Critical to the design is the logic for the signalling functions of optically (and electrically) combined lamps on trailers. Specifically, when the hazard warning system is actuated and the service brakes are applied, should the trailer warning lamps flash or be steady-burning? FMVSS 108 does not provide explicit direction.

We request a position from the DOT whether the lamps should flash or be steady burning in the above situation.

Very truly yours,

Daniel I. Borovik Director of Development and Planning

DIB/lg