Interpretation ID: aiam4683
OH 43081-6114;
Dear Tracey Powell: This is in reply to your letter of November l4 l989, with respect to existing prohibitions in some States against the use of modulating headlamps on motorcycles. The apparent basis of the prohibition is that flashing lamps are generally reserved for emergency vehicles. You point out the distinction that Standard No. 108 makes between the two types of headlamps, and ask our 'assistance in attaining uniform recognition of the legal use of modulating headlights through the United States . . . .' As you note, there is a legal distinction in Standard No. 108 between a modulating headlamp (one that goes from a higher to a lower intensity within either the upper or lower beam) and a flashing one (one that goes from either the upper or lower beam to off). Further, section S5.6.1 of Standard No. 108 provides that 'A headlamp on a motorcycle may be wired to modulate.' The authority of States to regulate this aspect of motorcycle lighting is constrained by section l03(d) of the National Traffic and Motor Vehicle Safety Act (l5 U.S.C. 1392(d)). This section provides in pertinent part that: w henever a Federal motor vehicle safety standard . . . is in effect, no State. . . shall have any authority either to extablish, or to continue in effect, with respect to any motor vehicle. . . any safety standard applicable to the same aspect of performance of such vehicle. . . which is not identical to the Federal standard.' The effect of this provision of the Safety Act with respect to lighting is to expressly prohibit a State from enacting a law that forbids a manufacturer from installing headlamp modulators on motorcycles. I hope that this responds to your concerns. Sincerely, Stephen P. Wood Acting Chief Counsel /;