Interpretation ID: nht70-2.10

DATE: 05/15/70

FROM: AUTHOR UNAVAILABLE; R. H. Compton; NHTSA

TO: Fleet Cap'n Trailers, Inc.

TITLE: FMVSS INTERPRETATION

TEXT: This is in reply to your letter of April 29, 1970, to Mr. Rodolfo A. Diaz, Acting Associate Director, Motor Vehicle Programs, concerning the location of rear lamps on various models of your trailers.

From a review of the sketch attached to your letter, it appears that the tail, stop and turn signal lamps mounted on the trailer frame rearward of the fenders will meet the location requirements specified in Table IV of Federal Motor Vehicle Safety Standard No. 108. However, Standard No. 108, by reference to SAE Standard J588d, also re-requires that "--- visibility of the front turn signal to the front and the rear signal to the rear shall not be obstructed by any part of the vehicle throughout the photometric test angles for the lamps." The photometric test angles for turn signal lamps are specified in Table 2 of SAE Standard J575c. From your sketch it appears that the required visibility of the turn signal lamps, when mounted in the proposed location, would be partially blocked by the framework of the trailer. Mounting the lamps on the rear crossmember may therefore be necessary to provide the required unobstructed visibility.

For your information I am enclosing copies of Standard No. 108, SAE Standard J588d and SAE Standard J575c.