Interpretation ID: aiam4006
Esq.
Camel Square Suite 200E
4350 East Camelback Road
Phoenix
AZ 85018;
Dear Mr. Lindsley: This is in reply to your letter of July 3, 1985, to Mr. Vinson of m 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 lam 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 no 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