Mr. Alan Robinson
9 Romney Wynd
Clifton Park
Isle of Man IM8 3NJ
United Kingdom

Dear Mr. Robinson:

This is in reply to your FAX of June 23, 1997, to Richard Van Iderstine of this agency. Mr. Van Iderstine had furnished you previously with copies of interpretations regarding the use of electronic message boards "fixed to the rear of vehicles." You now present five certain conditions which you believe "must apply to permit legal use of such a message display."

The agency interpretations indicate that, in general, an electronic message board cannot be used as original equipment if it impairs the effectiveness of lighting equipment required under Federal Motor Vehicle Safety Standard No. 108. Nor can an electronic message board be installed in the aftermarket by certain persons (i.e., a manufacturer, distributor, dealer, or motor vehicle repair business) if this "makes inoperative" any lighting equipment originally installed in accordance with Standard No. 108. With respect to lighting devices, the agency deems impairment of effectiveness and a making inoperative as equivalent. Even if permissible under Federal law, electronic message boards may be prohibited by the various states of the United States.

Your letter has given us a chance to review the subject of electronic message boards. The recurring concern with any supplementary lighting device is its potential to distract other drivers sharing the roadway from understanding and responding to the lighting devices required by Standard No. 108. This is particularly true if the supplementary device is one emitting verbal messages which must be read and its information processed, as compared with, for example, a flashing signal indicating a turn. This is a "message" which is instantly understood upon perceiving it.

As a consequence of our review, we have concluded that electronic message boards have the potential to impair any rear lighting devices (or make them "inoperative"), including the hazard warning system. This is a warning signal readily recognized by other motorists. We have concluded that an electronic message board has the potential to impair the effectiveness of the hazard warning system.

Thus, in our opinion, electronic message boards are not permitted on motor vehicles that have been manufactured to conform to Standard No. 108. However, if an electronic message board is simple enough that a vehicle owner may install it without seeking help from a manufacturer, distributor, dealer, or motor vehicle repair business, the owner is violating no Federal law if (s)he installs and uses it, and the legality of its use is determinable under state laws. We are not conversant with these laws.

John Womack
Acting Chief Counsel