Mr. Warren M. Heath
Commander
Engineering Section
Department of California Highway Patrol
P. O. Box 898
Sacramento
CA 95804;

Dear Mr. Heath: Thank you for your letter of December 8, 1969, concerning alternat flashing of side marker lamps with turn signal lamps.; Alternate flashing sidemarker lamps are permitted in paragraph S3.5 o Motor Vehicle Safety Standard No. 108 for signaling purposes, however, they must not impair the effectiveness of the turn signal lamps as required in paragraph S3.1.2.; Sincerely, Charles A. Baker, Office of Standards on Accident Avoidance Motor Vehicle Safety Performance Service;