Interpretation ID: GF008360

Mr. Jeff Thompson
Vice President
Timpte Trailer Co.
1827 Industrial Drive
David City, NE 68632

Dear Mr. Thompson:

This responds to your recent letter addressed to Richard Van Iderstine regarding installation of certain auxiliary lighting. Specifically, you ask whether Federal Motor Vehicle Safety Standard (FMVSS) No. 108, Lamps, Reflective Devices and Associated Equipment, allows for installation of an auxiliary [1] three-light identification cluster between the taillamps at the lower edge of the trailer. With certain limitations, our answer is yes.

Table II of FMVSS No. 108 specifies that 3 red identification lamps must be located on the top rear of a trailer with an overall width of 80 inches or more, and as close as practicable to the top of the vehicle. Identification lamps must meet the requirements of SAE Standard J592e Clearance, Side Marker, and Identification Lamps, July 1972, incorporated by reference in FMVSS No. 108. Paragraph 2.4 of SAE J592e defines identification lamps as "lamps used in groups of three." Your letter and an attached illustration indicate that your trailer satisfies these requirements. We assume that the auxiliary three-light identification cluster would also satisfy these requirements, except for those related to the cluster being at the top of the trailer.

With respect to additional lamps, FMVSS No. 108 does not prohibit installation of auxiliary lighting equipment so long as this equipment does not "impair the effectiveness" of lighting required by the standard. Thus, the three-light identification cluster located at the bottom of the trailer would be acceptable if it does not impair the effectiveness of the required identification cluster at the top of the trailer or the required lamps located at the outer edges of the bottom of the trailer.

After studying your illustration, it appears that the auxiliary cluster would not impair the effectiveness of the required lighting. It would be located several feet below the required cluster, so it would be distinct from that cluster, e.g., it would not appear to be part of a six-lamp cluster. Moreover, it would be located close to the vertical centerline of the trailer, so it would be distinct from the required lamps at the outer edges of the bottom of the trailer. In addition, drivers are used to seeing identification lamps in the same basic location on certain kinds of trailers such as flat-bed trailers.

We note that States also regulate auxiliary lighting devices in various ways.

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.

Sincerely,

Jacqueline Glassman
Chief Counsel

ref:108
d.1/14/04