Interpretation ID: nht90-4.35

TYPE: Interpretation-NHTSA

DATE: October 5, 1990

FROM: Gordon Bonvallet - Consulting Lighting, Engineer

TO: Paul Jackson Rice -- Chief Counsel, NHTSA

TITLE: Re FMVSS 108, Request for interpretation

ATTACHMT: Attached to letter dated 12-24-90 from Paul Jackson Rice to Gordon Bonvallet (A37; Std. 108)

TEXT:

This request for interpretation of ruling of FMVSS 108 is being made for HELLA KG, Lippstadt, Germany. Please direct any questions and the NHTSA response to the above address.

A design consideration for a future automotive vehicle headlamp system consists of four lamps, using gaseous discharge "integral beam" headlamps for the low beams and incandescent "replaceable bulb" (HB3) headlamps for the high beams. The gaseous discha rge lamp and the incandescent lamp on each side of the vehicle will be independent of each other but will share a common frame assembly. Each will be able to be replaced in part or completely without disturbing the other lamp.

The gaseous discharge lamp and ballast will be physically separated from each other but will be electrically connected with no means of disconnecting either component from the other. If either the lamp or ballast fails to operate, both components must b e replaced.

PHOTOMETRIC REQUIREMENTS: Although a combination gaseous discharge/incandescent system is not specifically addressed in FMVSS 108, it is our opinion that the Figure 15 photometric requirement would apply to both the low beam and the high beam lamps. Ple ase advise if this is correct.

AIMING REQUIREMENTS: At this time, it is anticipated that each individual lamp will have external aiming pads and therefore can be independently aimable. There is a possibility that an on-board aiming system of some type may be used. Are there any spec ial considerations that must be adhered to that are not specifically addressed in FMVSS 108?

It is our opinion that the above described system is allowable under FMVSS 108. We request that you review this concept and advise if you concur or if there are other factors that must be considered.