Interpretation ID: 17933.ztv

Mr. Jim Young
Supervisor
Electrical Engineering
Wheeled Coach
2737 North Forsyth Road
Winter Park, FL 32792

Dear Mr. Young:

This is in reply to your FAX of May 7, 1998, asking for interpretations of Federal Motor Vehicle Safety Standard No. 108 Lamps, Reflective Devices and Associated Equipment. Wheeled Coach is an ambulance manufacturer whose customer specifications may or may not be permitted by Standard No. 108.

Your "Case #1" concerns a customer request for "optically combining high intensity strobe warning lights with the front turn signals." These lamps are not synchronized with the turn signals, nor are they canceled when the turn signals operate. You also relate that the strobe lights are of greater intensity than that of the turn signals.

In your opinion, "it could be argued that the strobes could impair the effectiveness of the turn signals, thereby violating S5.1.3." We agree with your opinion. If the strobe lights are optically combined with the front turn signal lamps, are of higher intensity than those lamps, and are not canceled when the turn signals operate, impairment of the effectiveness of the front turn signals seems likely to occur. However, were the system designed so that the strobe lamps are canceled when the turn signals operate, then there would be no impairment or violation of S5.1.3.

You also mention that the turn signal employs a reflector and a lens to meet photometric requirements and that the reflector would have to have a hole drilled in it to accommodate the strobe tube. There is the possibility that the modification could affect compliance of the front turn signal lamp with applicable requirements. In addition to testing the headlamp with the modified reflector for continued compliance with headlamp photometric requirements, Wheeled Coach should also ensure that the modified headlamp continues to conform with other requirements demonstrating the integrity of the lens/reflector/bulb unit of replaceable bulb headlamps, most importantly the sealing, corrosion, dust, and humidity test requirements.

As the manufacturer of the ambulance, Wheeled Coach has the responsibility of certifying compliance of the vehicle to all applicable Federal motor vehicle safety standards.

Your "Case #2" concerns a customer request for "optically combining high intensity strobe warning lights with the headlights." The headlamps are replaceable bulb types and the reflector in this option also would require modification to accommodate the strobe tube.

You do not mention the operating characteristics of this system. In our opinion, in order not to impair the effectiveness of the headlamp system, the strobe lamps must be canceled at any time the headlamps are activated. If the headlamps on the original vehicle are wired to act as daytime running lamps (DRLs), it is permissible to disconnect them because DRLs are not a required item of lighting equipment. As indicated in the discussion under Case #1, it would be prudent for Wheeled Coach to test the modified headlamps for compliance for photometric and other requirements.

If you have other questions, you may call Taylor Vinson of this Office (202-366-5263).

Sincerely,
Frank Seales, Jr.
Chief Counsel
ref:108
d.6/23/98