Interpretation ID: aiam0091
Commander
Engineering Section
Department of California Highway Patrol
P.O. Box 898
Sacramento
CA 95804;
Dear Mr. Heath: Thank you for your letter of July 2, 1968, to Mr. George C. Nield Acting Director, Motor Vehicle Safety Performance Service, concerning requirements for combination clearance and side marker lamps.; Paragraph S3.3 of Motor Vehicle Safety Standard 108 permits th combination of two or more lamps providing the requirements for each are met. Table I in SAE Standard J592b gives the photometric requirements for both the clearance and side marker lamps, and Section J of the Standard permits their combination providing the combination complies with both clearance and side marker minimum candlepower requirements. Section J also defines the H-V axis of the combination as parallel with the longitudinal axis of the vehicle when checking clearance lamp test points, and normal to this vehicle axis when checking side marker test points.; Your table of minimum candlepower requirements for the Type combination lamp meets J592b and therefore Standard No. 108 providing you define the H-V axis as that of the side marker lamp. The requirements for the Type 1 combination as specified in your table will not meet J592b or Standard No. 108 unless you change H-10, -20, -30, -45, -60, - 80 and -90, both L and R to H-15, -25, -35, -45, -55, -65, -75 and -90, both L and R, and define the H-V axis as a line through the center of the lamp at a 45 degree angle to the longitudinal axis of the vehicle.; Your mounting instructions are considerably more restrictive than thos implied in J592b and Standard No. 108. Actually, no additional mounting instructions are necessary, because any mounting which meets the minimum candlepower requirements of Table I in J592 and your table with the suggested revisions would meet the requirements of Standard No. 108.; Sincerely, David A. Fay, Office of Standards on Accident Avoidance Motor Vehicle Safety Performance Service;