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Interpretation ID: aiam2764

Mr. W. W. Schwartz, Technical Engineer, Research and Development Dept., Vetter Fairing Company, 1150 Laurel Lane, San Luis Obispo, CA 93401; Mr. W. W. Schwartz
Technical Engineer
Research and Development Dept.
Vetter Fairing Company
1150 Laurel Lane
San Luis Obispo
CA 93401;

Dear Mr. Schwartz: This is in reply to your letter of February 1, 1978, on motorcycl headlighting.; You have asked whether the prohibition in SAE J580a *Sealed Bea Headlamp* against headlamp covers applies to a motorcycle. You have also asked the reason for the prohibition.; Sae J580a *Sealed Beam Headlamp* is incorporated by reference in Tabl III of Standard No. 108 as one of the standards applicable to headlamps for use on multipurpose passenger vehicles, trucks, and buses whose overall width is less than 80 inches. One of the SAE standards incorporated by reference for motorcycle headlighting is J584 which, as an option, allows motorcycles to be equipped with headlamps 'meeting the requirements of SAE J579' (i.e. passenger car sealed beam headlamps). There is no reference in J479a to J580a, and we therefore do not read the prohibition against headlamp covers as applying to motorcycles equipped with sealed or unsealed headlamps.; The reason for the prohibition is the degradation in light output tha can result from condensation under unsealed glass covers or from obscuration by grilles in front of the lens.; Sincerely, Joseph J. Levin, Jr., Chief Counsel