Interpretation ID: nht90-2.29

TYPE: Interpretation-NHTSA

DATE: April 25, 1990

FROM: Stephen P. Wood -- Acting Chief Counsel.,NHTSA

TO: Dipl.-Ing. H. Westermann -- Hella KG Hueck & Co.

TITLE: None

ATTACHMT: Attached to letter dated 2-21-90 To Taylor Vinson and From Dipl.- H. Westermann; (OCC 4484); Also attached to letter dated 2- 7-90 To Richard van Iderstine and From Dipl.- H. Westermann.

TEXT:

This is in reply to your letter of February 21, 1990, to Taylor Vinson of this office, requesting an interpretation of Motor Vehicle Safety standard No. 108 with respect to whether two designs for center highmounted stop lamps (CHMSL) you enclosed are permissible. You wish to know whether tbe ECE definition of "lamp unity" can be applied, and whether the designs form a CHMSL unity in the sense of Standard NO. 108. The question, as we see it, is not whether the ECE definition can be applied, but whether the two designs you submitted would meet the clearly expressed requirements of standard No. 108. The standard requires that there be a single lamp, that it have an effective projected luminous area of not less than 4 1/2 square inches, that its signal be visible through a horizontal angle from 45 degrees to the left to 45 degrees to the right of the longitudinal axis of the vehicle, and that it provide specified minimum photometric values at 13 specific test points. The design represented in Enclosure 1 appears to pass through the center of the lamp, at the H-V test point, thus affecting compliance of the lamp. Measurement at test points can only be determined by photometric testing. The design represented in Enclosure 2 would not comply with the standard. It is, in effect, two lamps mounted symmetrically about the vertical centerline. standard No. 108 requires a single lamp, to be mounted on the vertical centerline.