Interpretation ID: 1985-03.26

TYPE: INTERPRETATION-NHTSA

DATE: 08/06/85

FROM: AUTHOR UNAVAILABLE; Jeffrey R. Miller; NHTSA

TO: Warren F.B. Lindsley, Esq.

TITLE: FMVSS INTERPRETATION

ATTACHMT: 8/22/85 letter from Jeffrey R. Miller to Leo Kagan

TEXT:

Warren F. B. Lindsley, Esq. Camel Square Suite 200E 4350 East Camelback Road Phoenix, Arizona 85018

This is in reply to your letter of July 3, 1985, to Mr. Vinson of my staff, with reference to the center high-mounted stop lamp, in which you have asked "whether a light which pulsates a few times and then assumes a steady state meets the requirements of the code."

As Mr. Vinson explained to you, a center high-mounted stop lamp installed as original equipment on a passenger car manufactured before September 1, 1986, must be steady-burning in use, but is permitted to flash automatically with the hazard warning system. As of September 1, 1986, original equipment lamps must only be activated upon application of the service brakes, and can only be steady-burning. A "light that pulsates a few times then assumes a steady state" would not fulfill this requirement.

The standard does not cover aftermarket equipment for vehicles not originally manufactured with the center high-mounted stop lamp. For this application, the law of each State where a retrofitted car would be operated would determine the legality of a pulsating/steady state lamp. The agency, of course, would prefer that aftermarket equipment conform as closely as possible to original vehicle equipment specifications. We believe that standardization of rear signals minimizes the possibility of creating confusion to following drivers in situations where immediate action is essential to avoid a rear end collision.

Sincerely,

Jeffrey R. Miller Chief Counsel

(See 8/22/85 letter from Jeffrey R. Miller to Leo Kagan)

July 3, 1985

ATTN: Attorney Taylor Vincent

Re: High Mounted Rear Brake Light Title 49 Revised October 1, 1984 Pages 243-244

Dear Mr. Vincent:

I appreciated talking with you recently about the above subject wherein you told me that the code required, after September 1, 1986, a steady state light in the rear of the car, not a flashing light.

My clients have asked me to inquire of you whether a light which pulsates a few times and then assumes a steady state meets the requirements of the code.

It is their position that initial short pulsating or flashing of the light followed by a steady state condition would alert the driver of a following vehicle quicker than a constant steady state condition.

Since an answer to this question is important to my clients, and has a bearing on their financial investment in the development of such a light, I would appreciate receiving your comments in the near future.

Very truly yours,

Warren F. B. Lindsley Patent Attorney

WFBL/mc

Mr. Leo Kagan Director of Marketing Automotive Division Amco Manufacturing Corporation 7425 Fulton Avenue North Hollywood, CA 91605