Interpretation ID: aiam2288
4136 Loganway
Youngstown
OH
44505;
Dear Mr. Kupensky: This is in reply to your letter of April 8 to the Department o Transportation, regarding your CAUTION and THANK YOU signals which would flash simultaneously with the turn signal lamps on trucks and trailers.; Since such signs, flashing CAUTION or THANK YOU when actually 'turn' i intended, may be confusing in many circumstances, they would be prohibited by paragraph S4.1.3 of Federal Motor Vehicle Safety Standard (FMVSS) No. 108, 'Lamps, Reflective Devices and Associated Equipment,' (copy enclosed), because they would appear to impair the effectiveness of the turn signals. If these signs were manually operated by the driver, separately from the turn signals, at appropriate times, whether flashing or steady burning, they would be considered auxiliary devices which did not impair the effectiveness of the turn signals, and would be permitted by Standard No. 108. In this situation, however, they would be subject to the motor vehicle regulation of the individual States.; Sincerely, E. T. Driver, Director, Office of Crash Avoidance, Moto Vehicle Programs;