Interpretation ID: aiam3414
Executive Director
Vehicle Regulations
Volkswagen of America
Inc.
27621 Parkview Boulevard
Warren
MI 48092;
Dear Mr. Haenchen: This is in reply to your letter of May 27, 1981, asking for a interpretation of Motor Vehicle Safety Standard No. 108. Your company is considering, for fuel economy purposes, use of an engine stop/start system by which the engine would be switched off within a few seconds after a vehicle has come to a complete stop, and, to save battery capacity, the headlamps would also be deactivated. The parking lamps, however, will remain on. You believe that Standard No. 108 would not preclude such a system.; Although your letter does not mention it, we assume that when th parking lights are activated, the taillamps, license plate lamps, and side marker lamps would also be on, as required by S4.5.7(a) of Standard No. 108. The question then arises whether the system described is prohibited by paragraph S4.1.3 which states that 'No...motor vehicle equipment shall be installed that impairs the effectiveness of lighting equipment required' by Standard No. 108. Although the primary function of headlamps is to illuminate the roadway in front of the driver at night or under conditions of reduced visibility, they also serve to indicate the presence of the vehicle to traffic approaching from the opposite direction. In a situation where, on a two-lane road, a car has pulled to the shoulder temporarily, a headlamp will be perceived at a greater distance than a parking lamp to oncoming traffic. Headlamps also serve an illuminating function when people have paused in unfamiliar neighborhoods in an effort to discern their whereabouts. We believe, therefore, that your device could be viewed as impairing the effectiveness of headlamps within the meaning of S4.1.3.; This, however, is not a view dispositive of the issue. Compliance wit Standard No. 102 would also appear to be affected as that standard requires that the engine starter be inoperable when the transmission shift lever is in the forward or reverse position. Last year the agency granted a rulemaking petition with respect to an engine stop/start system such as you have discussed. I enclose a copy for your information. Although no notice has yet been published on this question, we shall endeavor to include a reference to headlamp switching devices in any future rulemaking activity on this subject.; Sincerely, Frank Berndt, Chief Counsel