Vice President - Engineering
Truck Trailer Manufacturers Association
1020 Princess Street
Alexandria, VA 22314-2247
Dear Mr. Vierimaa:
This is in response to your letter of March 17, 1997, with respect to my letter of September 4, 1996, to John W. Cook of Pace American, Inc.
Mr. Cook had informed us that he had fenders that attached to the side of his trailers in widths that vary from 2 to 11 inches. He asked whether it was acceptable for the clearance lamps to be within 6 to 8 inches from the outermost part of the trailer including fenders. We replied that in our judgment, locating a clearance lamp within 6 to 8 inches of the outermost edges of a trailer does not indicate "overall width" within the meaning of Standard No. 108. You have asked whether this interpretation was intended to apply only to the Pace American design, or applicable to all trailers. You are presently recommending to your members that the front clearance lamps be located within 16 inches of the side of the trailer.
Table II of Standard No. 108 requires clearance lamps to be located to indicate the overall width of the trailer. The optimum location for clearance lamps is therefore at the extreme width of the trailer. The further inboard that clearance lamps are located from the extreme edge of the trailer, the less they indicate the overall width of the trailer.
The Pace American trailers were equipped with fenders, whereas your question pertains to front clearance lamps only, and mounted on trailers without fenders (designs on pages 12-18 of RP No. 9, which you enclosed). These designs show a location zone for front clearance lamps within 16 inches from the side of the trailer. The drawings also bear the legend "Center of front clearance lamps shall be within indicated zones." We don't believe that a lamp center, say, at 15 inches inboard represents location of a lamp that indicates "overall width". In our judgment, locating a clearance lamp more than 6 inches from the outermost edge of a trailer that is 80 or more inches in overall width does not indicate "overall width" within the meaning of Standard No. 108.
If you have any questions on this letter, you may call Taylor Vinson (202-366-5263).
Acting Chief Counsel