Interpretation ID: 20747.ztv

Mr. George Manset
Director of Engineering
Martin Industries
P.O. Box 128
Florence, AL 35631

Dear Mr. Manset:

This is in reply to your letter of September 14, 1999, to Rich Van Iderstine, with respect to whether your prospective location of taillamps on utility trailers complies with Federal Motor Vehicle Safety Standard No. 108.

Your current practice is to locate taillamps "on the very rear of the trailer (which have total lengths of 96" and 132")." You are considering locating these lamps in the fenders "which are 12" and 30" from the rear on the respective trailers." You observe that for many trailer designs, with tilt features and loading ramps, "it isn't always practical to be located directly on the rear." Mr. Van Iderstine tells us that these designs may also affect the location of other rear lighting equipment such as stop and turn signal lamps, and perhaps license plate lamps and clearance lamps as well.

Paragraph S5.3.1 of Standard No. 108 requires motor vehicle lighting equipment to be mounted in the location specified in Table II or Table IV of Standard No. 108. Each Table requires stop, turn signal, clearance, and taillamps to be mounted "on the rear." Further, S5.3.2 requires each lamp to be located "so that it meets the visibility requirements specified in any applicable SAE Standard." The applicable SAE Standards are indicated in Table I and Table III.

As you know, lamps must be designed to meet minimum candlepower specifications measured at various test points. In general, the visibility of lamps must not be obstructed by any part of the vehicle throughout the photometric test angles for the lamp, unless the lamp is designed to comply with all photometric and visibility requirements with the obstructions considered. Further, the signal from lamps on both sides of the vehicle must be visible through a horizontal angle from 45 deg. to the left to 45 deg. to the right. To be considered visible, the lamp must provide an unobstructed projected illuminated area of outer lens surface, excluding reflex at least 2 sq. in (12.5 sq. cm.) in extent, measured at 45 deg. to the longitudinal axis of the vehicle.

Enclosed are three letters which address issues raised by your question. You will see from our letter of January 29, 1996, to Tommy Reeder, that it is not necessary to locate lamps literally on the extreme end of a tilt bed trailer provided that the photometric and visibility requirements of Standard No. 108 are met in the location chosen. We informed Jack Rademacher on August 22, 1990, that we interpret "on the rear" as meaning the trailing edge of the rear fender, providing the visibility requirements were met. If your taillamps meet all the visibility requirements when mounted in the trailing edge of a rear fender 12 inches from the extreme end of the trailer, we would consider the lamps as mounted "on the rear." However, our letter of January 8, 1990, to Howard Kossover stated that lamps mounted 27 inches from the rear edge of the vehicle were not mounted "on the rear" as the standard specifies; further, we had reservations whether the visibility requirements could be met in that location. This means that your contemplated location of 30 inches would not comply with Standard No. 108 as we have interpreted it.

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

Sincerely,
Frank Seales, Jr.
Chief Counsel
Enclosures
ref:108
d.11/16/99