Reiter & Schefenacker
Dear Herr Sandig:
This replies to your FAX of May 28, 1996, asking whether a proposed design for a center highmounted stop lamp is a single lamp, within the meaning of Federal Motor Vehicle Safety Standard No. 108.
In this design, a rectangular lens is separated by an opaque oval that covers the center portion of the lens. However, the sum of the effective projected luminous lens areas left uncovered exceeds the minimum 4.5 square inches required by paragraph S22.214.171.124(a)(1) of Standard No. 108.
This design does not comply with Standard No. 108. Paragraph S126.96.36.199 (a) requires vehicles to be equipped with "a high-mounted stop lamp." Table IV requires the lamp to be located "on the vertical centerline." The opaque area in your design functionally divides the center lamp into two lamps, neither of which is located on the vertical centerline.
In the past, the agency has advised that the lens of the center stop lamp may be obscured to a certain extent by decals or other trim, provided the minimum luminous lens area requirement was met, and the obscuration did not affect photometric compliance. These interpretations always assumed that the appearance of a single lamp would be maintained, even though the lens area itself did not present an uninterrupted light-emitting surface.
Paragraph S188.8.131.52(b) does allow two separate lamps on vehicles other than passenger cars when there is insufficient space above doors opening from the center, but your lamp is not designed to address this problem.
If you have any questions, you may refer them to Taylor Vinson of this Office.
Samuel J. Dubbin Chief Counsel ref:108 d:6/14/96