Interpretation ID: 2908yy
Manufacturers Representative
442 Robin Hill Road
Wayne, PA . 19087
Dear Mr. McAllister:
This responds to your letter of March 14, l99l, "as a supplier to the U.S. Postal Service for lights", asking whether it is "legal" for the center high mounted stop lamp to flash.
We understand that the new postal service vehicles are trucks. Under Federal Motor Vehicle Safety Standard No. 108, the center highmounted stop lamp is required only on passenger cars. When installed as original equipment on a passenger car, it is required to be steady-burning when the brake pedal is applied. However, since Standard No. 108 does not require center highmounted stop lamps on motor vehicles other than passenger cars, any such lamps would not be required to be steady-burning. Thus, the current requirements of Standard No. 108 would permit a center lamp on a postal truck to flash.
Supplementary lighting equipment, i.e., lighting equipment that is not required by Standard No. 108, is subject to Standard No. 108's general prohibition that such not impair the effectiveness of the lighting equipment required by the standard. The determination of impairment is to be made by the manufacturer of the vehicle before it certifies compliance with all applicable Federal motor vehicle safety standards. If it appears to be clearly erroneous, NHTSA will review the determination. With respect to the present case, it is theoretically possible that a flashing center stop lamp could "impair the effectiveness" of the truck's two steady-burning primary stop lamps by sending a confusing signal. However, given the lamp's location on the vertical centerline of the vehicle, and the public recognition of the function of the center lamp on passenger cars, we do not believe it is likely that the public would be confused.
We would like to advise you that the agency has proposed that trucks be equipped with steady-burning center lamps, and that it has announced that a final rule will be issued during the first half of 1991. If the final rule applies to postal trucks, then a flashing center lamp could not be installed on postal trucks manufactured on and after the rule's effective date.
Sincerely,
Paul Jackson Rice Chief Counsel
Ref. l08 d:4/3/9l