Interpretation ID: 20937.ztv

Dear:

This is in reply to your letter of November 4, 1999, asking whether a lighting device you describe would be permissible under Federal Motor Vehicle Safety Standard No. 108. You requested that we keep your letter and our reply "in strict confidence." As Taylor Vinson of this Office informed you on December 2, 1999, our interpretations are publicly available and must contain sufficient information for the general public to understand the question being asked and our response to it. We can ensure that publicly available copies of interpretation letters do not identify the writer or the company involved, and you agreed that we could provide you an interpretation on this basis.

You report that "tractor/trailer combinations today have areas around the vehicle where the driver cannot see other vehicles that are passing them. These blind spots in the mirror systems can cause accidents." You are interested in a lighting device that " would be mounted high on the side of a trailer and would shine a light beam (laser or other type of lighting device) down and across the adjacent traffic lane." The light "would shine on the hood of a passing vehicle" thereby providing the driver with a warning that they are in the tractor trailer's blind spot." The color of the light would be yellow, blue, or red.

Under Standard No. 108, non-standard lighting devices are permitted as original equipment if they do not impair the effectiveness of lighting devices required by Standard No. 108. Although this device would not appear to impair the effectiveness of standard lighting equipment, we are concerned that it might impair driver performance. Our principal reservation about new lighting concepts such as this is that they are unfamiliar to drivers and will cause confusion, diverting attention from critical driving tasks. In this case, a driver finding a red, amber, or blue light suddenly shining on the vehicle hood may instinctively turn to see where it is originating, or brake when there is no need to do so. When a vehicle is traveling faster than a trailer on which the device is mounted, the light beam could proceed from the hood into the passenger compartment, at least on open cars, possibly temporarily blinding the driver. Thus, the device you describe could create actual hazards.

You must remember, too, that a state may apply its own laws to auxiliary lighting devices and require specific approval to use them. Virtually all states reserve the color blue for emergency signals. Standard No. 108 does not permit side marker lamps and reflectors to be red except when they are mounted as far to the rear as practicable, and we apply this requirement to auxiliary side lighting devices as well.

If you have further questions, you may call Taylor Vinson (202-366-5263).

Sincerely,
Frank Seales, Jr.
Chief Counsel
ref:108
d.6/19/00