Interpretation ID: aiam5398
FAX 07142/73-2895 Dear Herr Binder: This responds to your FAX of Apri 28, 1994, to Taylor Vinson of this Office, requesting an interpretation of Motor Vehicle Safety Standard No. 108. Your letter shows a rear motor vehicle lighting array of four lamps, two on the body ('Rearlamp 1') and the other on the tailgate ('Rearlamp 2'). The four lamps appear to be equal in size. You cite the requirement of Standard No. 108 and 'SAE J588e Sept. 77' that the lamp must 'provide an unobstructed projected illuminated area of 12.5 cm2 measured at 45 deg.' and state that this 'will not be performed by Rearlamp 1 because of the tailgate, however, the requirement is met by Rearlamp 2 and will be met by Rearlamp 1 if the tailgate is open. You have asked whether such a system is allowed. First, a correction. There has never been a standard known as 'SAE J588e Sep. 77.' We believe that your are referring to SAE Standard J588e September 1970, which is incorporated by reference in Standard No. 108, but now applies only to certain replacement turn signal lamps (See S5.8.4(b)). The standard that applies to new passenger car designs such as you have depicted is SAE J588 NOV84 Turn Signal Lamps for Use on Motor Vehicles Less than 2032 mm in Overall Width. The visibility requirements, however, remain as you have stated. They are set forth in paragraph 5.4.1 of SAE J588 NOV84. As you have noted, the turn signal lamps must be visible through horizontal angles of 45 degrees to the right or left, depending on whether they are mounted on the right or left. To be considered visible, 'the lamp must provide an unobstructed view of the outer lens surface . . . of at least 12.5 cm2 measured at 45 deg. to the longitudinal axis of the vehicle.' We believe that the design depicted is in accordance with Standard No. 108. It is, in operation, a turn signal lamp system of two lamps on each side of the vehicle. Contrary to your assertion, we believe that the outer lamp on each side, Rearlamp 1, will meet the visibility requirements when the tailgate is in place because visibility must be met only at 45 degrees outboard (the agency judges compliance with the vehicle in its normal operating condition, that is to say, with the tailgate closed). Thus, under Standard No. 108, Rearlamp 2 is regarded as a permissible supplementary turn signal lamp. I hope that this is helpful to you. Sincerely, John Womack Acting Chief Counsel;