Interpretation ID: nht87-1.12

TYPE: INTERPRETATION-NHTSA

DATE: 01/12/87

FROM: AUTHOR UNAVAILABLE; Erika Z. Jones; NHTSA

TO: T. Chikada

TITLE: FMVSS INTERPRETATION

TEXT:

Mr. T. Chikada Manager, Automotive Lighting Engineering Control Dept. Stanley Electric Co., Ltd. 2-9-13, Nakameguro, Meguro-ku Tokyo 153, Japan

Dear Mr. Chikada:

This is in reply to your letter of November 21, 1986, with reference to the distance between a front turn signal lamp and a lower beam headlamp.

In brief, SAE Standard J588e, incorporated by reference in Standard No. 108 requires a minimum separation distance of 4 inches between the optical axis (filament center) of the front turn signal lamp to the inside diameter of the retaining ring of the lo wer bean headlamp. You have pointed out that a replaceable bulb headlamp does not have a retaining ring, and you have presented two possible substitutes as a measuring point. The first (your Item A) is the outer edge of the headlamp, and the second (your Item B) is the end of the effective area of the reflector. You believe that Item B is the more appropriate.

We concur with your interpretation. Of the two options, the distance to the edge of the effective area of the reflector is the one most similar to the inside diameter of the retaining ring of the lower beam headlamp. The basis for this interpretation is the assumption that the headlamp lens between the outer edge of the headlamp and the edge of the effective area of the reflector is not used for production of the lamp's bean, has mo significant luminance, and therefore will not mask the turn signal.

Sincerely,

Erika Z. Jones Chief Counsel

November 21, 1986

Erika Z. Jones Chief Counsel Department of Transportation National Highway Traffic Safety Administration 400 Seventh Street, S.W. Washington, D.C. 20590 U.S.A.

Dear Ms. Jones,

Re : Distance between a front turn signal lamp and a low beam headlamp)

In Motor Vehicle Safety Standard N0.108, Paragraph 4.3.1.7, the following is prescribed:

S4.3.1.7 The requirement that there be not less than 4 inches between a front turn signal lamp and a low beam headlamp, specified in SAE Standard J588e, "Turn Signal Lamps," September 1970, shall not apply if the sum of the candlepower values of the turn signal lamps Measured at the test point within each group listed in Figure 1c is not less than two and one-half times the sum specified for each group for yellow turn signal lamps.

According to the SAE Standard J588e, the distance is defined as from the optical axis (filament center) of the front turn signal lamp to the inside diameter of the retaining ring of the headlamp unit providing the lower beam. This definition applies only to a standardized headlamp. What definition is appropriate for a replaceable bulb headlamp, in other words, an unstandardized headlamp? We think B in the following definition is appropriate.

A : From the filament center of the front turn signal lamp to the outer edge of a low beam headlamp

B : From the filament center of the front turn signal lamp to the end of the effective area of the reflector of a low beam headlamp

SEE HARD COPY FOR GRAPHIC ILLUSTRATION