Interpretation ID: aiam3060
National Service Manager
Vespa of America Corporation
355 Valley Drive
Brisbane
CA 94005;
Dear Mr. Beyer: This is in reply to your letter of June 20, 1979, asking for a interpretation of Federal Motor Vehicle Safety Standard No. 108 as it relates to operation of turn signal lamps by alternating current. You have informed us that Vespa wishes to use such a system on its 1980 motor driven cycles, and you have asked what SAE Standard or method must be followed by the lamps to comply.; Table III of Standard No. 108 requires that any motor driven cycles whose speed attainable in 1 mile exceeds 30 mph, be equipped with a turn signal flasher meeting SAE Standard J590b, *Turn Signal Flasher*, October 1965. The scope of this SAE Standard is that the specifications 'are for nominal 12 or 6 v - dc circuits ....' We construe this to mean that the typical electrical system of a motorcycle is designed to utilize direct current (dc), so that the alternate current (ac) flow from the alternator must be rectified (changed) to dc.; We would have no objections, however, to a turn signal system fed b alternating current if Vespa could demonstrate that such turn signal flashers and lamps would meet all performance requirements of SAE Standard J590b, *Turn Signal Flashers*, as well as the other requirements set forth in Standard No. 108.; Sincerely, Frank Berndt, Chief Counsel