Interpretation ID: aiam3847
Vice President - Marketing
Wesbar Corporation
Box 577
West Bend
WI 53095;
Dear Mr. Nielsen: This is in reply to your letter of May 16, 1984, to Mr. Vinson of thi office seeking an interpretation of Motor Vehicle Safety Standard No. 108. You wish to know whether the minimum effective projected luminous lens area for stop lamps and turn signal lamps on trailers whose overall width is 80 inches or greater is 8 square inches or 12 square inches. You cite an apparent conflict between paragraph S4.1.1.6 and SAE Standard J586d, and paragraph S4.1.1.7 and SAE Standard J588f. You have asked for an interpretation so that Wesbar may properly design a 'combination tail lamp.'; First, we will confirm the advice provided by 'D.O.T. staff people that the latest SAE revisions, J586d and J588f, have not been adopted.; You do not state the intended use of your proposed lamp, so we wil assume that it will be sold to trailer manufacturers as original equipment, and to the aftermarket as replacement equipment. As original equipment, it must comply with the requirements specified in Table I of Standard No. 108, SAE J586c for stop lamps and SAE J588e for turn signal lamps. Paragraph 3.2 of each standard specifies a minimum effective projected luminous lens area of 8 square inches.; Paragraphs S4.1.1.6 and S4.1.1.7 become relevant, however, if Wesba intends the lamp as replacement equipment on trailers manufactured before September 1, 1978, and after January 1, 1972 (turn signal lamps) and January 1, 1973 (stop lamps). Under paragraphs S4.1.1.6 and S4.1.1.7, replacement stop and turn signal lamps for trailers manufactured within the 1972-1978 time frame may meet either J586b or J586c, and either J588d or J588e. We note that neither J586b nor paragraph S4.1.1.6 establish a minimum luminous lens area for stop lamps. However, a manufacturer who chooses to comply with paragraph S4.1.1.7 rather than J588e would have to provide the minimum specified luminous lens area of 12 square inches for turn signal lamps of trailers whose overall width was 80 inches or more, the requirement specified in J588d for Class A turn signal lamps. We view this interpretation as one of historical interest than (sic) current relevance.; In summary, if Wesbar designs its lamp to the 8-inch requirement, i would appear to meet specifications for application either as original or replacement equipment.; Sincerely, Frank Berndt, Chief Counsel