Interpretation ID: aiam5015
Dear Herr Spingler: This responds to your letter of April 3, 1992, t Mr. Van Iderstine of this agency asking for a 'quick answer' to your question regarding the acceptability of a new headlamp design. Please be advised that my Office is the one to which questions of interpretation of Motor Vehicle Safety Standard No. 108 should be addressed, and that correspondence addressed to the Chief Counsel allows us to respond more quickly to the concerns of the writer. We understand that you discussed the headlamp with Mr. Van Iderstine on his recent trip to Europe, and that it will be used in a replaceable bulb headlighting system that is governed by S7.5 of Standard No. 108. Your proposed headlamp incorporates a lower beam provided by an ellipsoid and an upper beam provided by a parabola. The drawing you enclosed shows the lower beam source above the upper beam source. When the upper beam is on, both bulbs will be activated simultaneously. Where, as in your design, each headlamp contains two light sources, S7.5(d)(2)(i)(A) and S7.5(e)(2)(i)(A) specify that the lower beam shall be provided by the outboard or uppermost light source. S7.5(d)(2)(ii)(A) and (B) and S7.5(e)(2)(ii)(A) and (B) specify that the upper beam shall be produced by the lowermost, or both, light sources. The beams in your headlamp are provided in this manner, and, therefore, are in accordance with the requirements of Standard No. 108. Sincerely, Paul Jackson Rice Chief Counsel;