Interpretation ID: nht80-3.15

DATE: 07/07/80

FROM: AUTHOR UNAVAILABLE; F. Berndt; NHTSA

TO: BMW of North America, Inc.

TITLE: FMVSS INTERPRETATION

TEXT: This is in reply to your letter of June 9, 1980, asking for an interpretation of Federal Motor Vehicle Safety Standard No. 108 with respect to the spacing required between headlamps and turn signal lamps on motorcycles.

You cited Table IV of Standard No. 108 which requires that the "minimum edge to edge separation distance between [turn signal] lamp and [headlamp] is 4 inches." You also cited paragraph 4.2 of the referenced SAE standard on turn signal lamps, J588e, which mandates that "the optical axis (filament center) of the front turn signal shall be at least 4 inches from the inside diameter of the retaining ring of the headlamp unit providing the lower beam." Finally, you have cited an agency interpretation of November 5, 1979, to Bajaj Auto Limited as support that the provisions of 4.2 prevail, and you asked for confirmation of this opinion.

The Bajaj letter does not provide the support you seek. The interpretation it provides is that the separation distance must be not less than the minimum under all motorcycle operating conditions.

We view Table IV as controlling in this instance as it contains a specific locational requirement for motorcycles. Since that specific requirement is lacking in Table IV for other motor vehicle, paragraph 4.2 of J588e would then apply with respect to separation distance for lamps on passenger cars, trucks, buses, and multipurpose passenger vehicles.

SINCERELY,

BMW OF NORTH AMERICA, INC.

June 9, 1980

Chief Counsel National Highway Traffic Safety Administration U.S. Department of Transportation

RE: Request for Interpretation FMVSS 108, Lamps, Reflective Devices, and Associated Equipment

Dear Sir

We request interpretation of the interlamp spacing requirements specified for motorcycles in Table IV of FMVSS 108.

A four-inch spacing is required between turn signal lamps and the edge of the headlamp in front, and between turn signal lamps in the rear. However, while subject table uses the words, "edge to edge", SAE J588e, referenced in Table III, specifies measuring turn signal distance from the filament center.

Acceptance of the filament center of a turn signal lamp as the measuring point is underscored by your letter of November 5, 1979 to Mr. Keshav of Bajaj Auto Limited.

A closely related question concerns the method of measurement, i.e., whether the required four-inch separation dimension is a physical measurement between lamps or a distance between lamp projections. This is questioned because the measurement method is not specified in Table IV, and because S4.3.1.1 of the standard, and section 4.3 of SAE J588e otherwise require unobstructed photometric compliance.

In view of the above, we interpret the standard to mean that the four-inch dimension is a physical measurement to a turn signal's filament.

We would appreciate receiving your interpretation as soon as convenient.

Karl-Heinz Ziwica, Manager Safety & Emission Control Engineering