Interpretation ID: nht68-3.49
DATE: 08/05/68
FROM: AUTHOR UNAVAILABLE; David A. Fay; NHTSA
TO: Department of California Highway Patrol
TITLE: FMVSS INTERPRETATION
TEXT: Thank you for your letter of July 1, 1968, to Mr. George C. Nield, concerning a clarification of paragraph S 3.4.3 of Federal Motor Vehicle Safety Standard No. 108.
Paragraph S 3.4.3 specifies that, as a minimum, the taillamps shall be illuminated when the headlamps are illuminated, except when the headlamps are being flashed. The phrase "except when the headlamps are being flashed", permits the vehicle manufacturer to use a separate switch or flasher for illuminating the headlamps only when it would not be appropriate or in the interest of safety to simultaneously illuminate the taillamps and headlamps. In addition to the examples cited in your letter, such devices could also be used for flashing the headlamps on public transit vehicles to indicate an emergency situation.
Since the subject matter of S 3.4.3 is taillamps and since Federal Standard No. 108 is otherwise silent as to headlamp flashing, this matter appears to be within the purview of the California vehicle code.
Thank you for your continued interest in the motor vehicle safety standards.