Mr. Timothy C. Murphy
    Vice President, Engineering
    Peterson Manufacturing Company
    4200 East 135th Street
    Grandview, MO 64030

    Dear Mr. Murphy:

    This responds to your letter dated August 18, 2004, asking whether strobing stop lamps or auxiliary lamps are permissible under the requirements of Federal motor vehicle safety standard (FMVSS) No. 108.

    By way of background, the National Highway Traffic Safety Administration (NHTSA) does not provide approvals of motor vehicles or motor vehicle equipment. Under 49 U.S.C. Chapter 301, manufacturers are required to certify that their vehicles and equipment meet applicable requirements. The issues raised by your letter are addressed below.

    The Federal standard applicable to lighting equipment, including stop lamps, is FMVSS No. 108, Lamps, Reflective Devices and Associated Equipment. The relevant sections of that standard read as follows:

    S5.5.10 The wiring requirements for lighting equipment in use are:

    (a) Turn signal lamps, hazard warning signal lamps, and school bus warning lamps shall be wired to flash;

    (b) Headlamps and side marker lamps may be wired to flash for signaling purposes;

    (c) A motorcycle headlamp may be wired to allow either its upper beam or its lower beam, but not both, to modulate from a higher intensity to a lower intensity in accordance with section S5.6;

    (d) All other lamps shall be wired to be steady-burning. [emphasis added]

    In short, S5.5.10(d) of FMVSS No. 108 mandates that all lamps be steady burning, unless otherwise explicitly permitted. In the present case, stop lamps do not fall under any exception enumerated in S5.5.10 (a) through (c). Accordingly, FMVSS No. 108 requires stop lamps to be steady burning. We regard a strobe lamp as one that flashes. For this reason, the strobing stop lamps described in your letter would be prohibited by FMVSS No. 108, if they are installed as original equipment on motor vehicles. They would also be prohibited from being sold as replacement for original equipment stop lamps. Further, unless auxiliary lamps mentioned in your letter fall under any exception enumerated in S5.5.10 (a) through (c), they must also be steady burning.

    This prohibition would also apply to aftermarket lighting installation because 49 U.S.C. 30122 prohibits manufacturers, dealers, distributors, and motor vehicle repair businesses from making inoperative safety equipment installed in accordance with FMVSS No. 108 (and any other applicable FMVSS as well). Accordingly, installation of a strobing lamp not permitted by S5.5.10 would create a noncompliance with FMVSS No. 108 which constitutes "making inoperative" within the meaning of the statute.

    The list of persons prohibited from making vehicle modifications affecting compliance in 49 U.S.C. 30122 does not include vehicle owners.

    I hope you find this information helpful. If you need further assistance, please contact George Feygin of my staff at this address or at (202) 366-2992.


    Jacqueline Glassman
    Chief Counsel