Interpretation ID: nht89-3.10

TYPE: INTERPRETATION-NHTSA

DATE: 10/06/89

FROM: STEPHEN P. WOOD

ACTING CHIEF COUNSEL NHTSA

TO: SADATO KADOYA --

MAZDA RESEARCH & DEVELOPMENT OF NORTH AMERICA, INC.

TITLE: NONE

ATTACHMT: LETTER DATED 8/24/89, FROM SADATO KADOYA OF MAZDA TO STEPHEN WOOD OF NHTSA RE REQUEST FOR INTERPRETATION - FMVSS 108: LAMPS, REFLECTIVE DEVICE AND ASSOCIATED EQUIPMENT

TEXT: Dear Mr. Kadoya:

This is in reply to your letter of August 24, 1989, with respect to an interpretation of paragraph S5.3.1.8 of Standard No. 108, as it applies to the location of center highmounted stop lamps.

The paragraph requires that no portion of the lens shall be lower than 3 inches below the rear window, if the lamp is mounted below the rear window. Your letter depicts two areas in which a lamp lens may be mounted, denoted "(A)" and "(B)". In both, th e lower edge of the rear window is curved. In "(A)", the boundary of the allowable area is curved, and follows the curve of the lower edge of the rear window at a parallel distance of 3 inches. In "(B)", the boundary of the allowable area is a straight line which measures 3 inches from the end of the lower edge of the rear window, but which is greater than 3 inches at all other points because of the curve of the window.

The initial requirement of paragraph S5.3.1.8 is that the highmounted lamp be "mounted with its center on the vertical centerline of the passenger car as the car is viewed from the rear." This means that the 3-inch distance is measured from the lower edg e of the rear window that is at the vertical centerline. Thus, your "(A)" is the correct location because the boundary line is 3 inches directly below the center point of the vertical centerline, and your "(B)" is not acceptable because its boundary line is more than 3 inches below that point.

I hope that this answers your question.

Sincerely,