Interpretation ID: aiam3030
Director of Engineering
Trailer Manufacturer Association
401 North Michigan Avenue
Chicago
IL 60611;
Dear Mr. Reed: This letter corrects an interpretation provided you on June 1, 1979. In our letter, we answered in the negative to your question whether: >>>'whether (sic) it is permissible to combine a clearance lam function in a tail lamp fixture if a second bulb is installed in the tail lamp which, when lit alone, satisfies the photometric requirements of the clearance lamp shown through the tail lamp lens ... and further assuming that all tail lamp photometric requirements are met when the tail lamp bulb alone is lit and when both lamps are lit.'<<<; We commented that such a lamp would appear to create the optica combination prohibited by S4.4.1 when both lamps are lit.; It has been brought to our attention that this conflicts wit interpretations provided on March 4, 1977, to Dennis Moore of Livermore, California, and B.R. Weber of West Bend, Wisconsin, both manufacturers of boat trailer lighting equipment. In our letter to Mr. Weber, for example, we interpreted 'optically combined' to mean a situation in which 'the same light source (i.e., bulb) and the same lens area fulfill two or more functions (i.e., tail lamp, and stop lamp, clearance lamp and turn signal lamp)'. The phrase is not intended to prohibit the installation of two separate bulbs in a single housing and covered by a common lens.; Upon review, we believe that the interpretation of March 4, 1977, i the correct one, and that the conflicting interpretation of June 1, 1979, should be with error. We are sorry for any confusion this may have caused your members.; Sincerely, Frank Berndt, Chief Counsel