Interpretation ID: nht73-1.24

DATE: 12/06/73

FROM: AUTHOR UNAVAILABLE; Lawrence R. Schneider; NHTSA

TO: Fruehauf Corporation

TITLE: FMVSS INTERPRETATION

TEXT: Thank you for your letter of November 20, 1973, asking whether you may install "lights as set forth in Example 1." In this example identification lamps would be mounted under the rear crossmember of the vehicle while "the combination tail and turn signal lamps (at the bottom) could serve as the clearance lamps."

The rear lighting scheme shown in your "Example 1" appears to be seriously at variance with Standard No. 108. There is a clear violation of paragraph S4.4.1 which forbids the optical combination of tail lamps and clearance lamps. Both clearance lamps and identification lamps must be located "as close as practicable to the top of the vehicle." The fact that you have developed a clearance lamp that can be mounted in the header area demonstrates that that is the "practicable" location, despite the fact that the header may be too shallow to accommodate the lamps specified by the customer. Further, since the performance required of clearance lamps is identical to that for identification lamps, and three of your clearance type lamps could serve as identification lamps and the header would appear to be the "practicable" location for the identification lamp arrangement as well.

Sincerely,

November 20, 1973

Richard Dyson National Highway Safety Administration, DOT

Ref: Lamps, Reflective Devices, and Associated Equipment Motor Vehicle Safety Standard No. 108

Dear Mr. Dyson:

We would like an interpretation of FMVSS No. 108 in the area of rear clearance lamps and identification lamps under the conditions outlined below:

Fruehauf Corporation has been asked to build a large number of van type trailers (over 80 inches in overall width) which incorporate a rear header too shallow to accommodate the identification lamps or clearance lamps specified by the customer.

The customer contends that due to the shallow header, it is not practicable to mount the identification lamps any higher than below the rear crossmember and that the combination tail and turn signal lamps (at the bottom) could serve as the clearance lamps.

EXAMPLE I (Graphics omitted)

Rear Header

Stop & Tail Lamp

Tail & Turn Signal Lamp

Identification Lamp

Fruehauf Corporation has a clearance lamp which could be installed in the shallow header and has proposed that they be installed at the top rear corners, with the identification lamps being installed below the rear crossmember.

EXAMPLE II

Clearance Lamp

Identification Lamp

The customer has refused to accept Fruehauf's proposed installation due to the clearance lamps not being compatible with the existing lamps in his large fleet, thus creating a hardship.

This order will be held in abeyance until we can get a ruling from your department as to whether we may install the lights as set forth in Example I and certify the vehicles as being in accordance with FMVSS No. 108.

Very truly yours,

FRUEHAUF CORPORATION -- R. O. Crider - Manager, Government Safety Standards and Regulation Compliance

cc: E. Chosy