Interpretation ID: nht89-2.76

TYPE: INTERPRETATION-NHTSA

DATE: 08/23/89

FROM: STEPHEN P. WOOD -- NHTSA ACTING CHIEF COUNSEL

TO: TAKAYOSHI CHIKADA -- MANAGER OF AUTOMOTIVE LIGHTING ENGINEERING CONTROL DEPT. STANLEY ELECTRIC CO., LTD.

TITLE: NONE

ATTACHMT: LETTER DATED 06/16/89 FROM TAKAYOSHI CHIKADA TO RICHARD L. VANIDERSTINE -- NHTSA; RE REVISION OF FMVSS NO 108 [DOCKET NO 85-15 NOTICE 8]

TEXT: Dear Mr. Chikada:

This is in reply to your letter of June 16, 1989, to Mr. Van Iderstine of this agency, by FAX as you requested. You have asked four questions with respect to the recently amended Federal Motor Vehicle Safety Standard No. 108.

We responded to your first two questions in a letter dated June 19 to Mr. Hasegawa of your office. A copy is enclosed for your reference. Since that time, however, in response to a petition by General Motors, we have changed the effective date of parag raph S7.7.5.1(a) to December 1, 1989, with respect to replaceable bulb headlamp systems. A copy of this notice is also enclosed.

Your third question is:

How should we prove the confirmation to the requirement of S7.7.2.2? We think the combination of Horizontal and Vertical angle within the aim range will be so huge and it is not practicable to test for all combinations.

This paragraph applies to headlamps aimed by moving the reflector relative to the lens and headlamp housing, or vice versa. The agency has frequently advised manufacturers that there is no legal requirement that conformance be demonstrated through the t est procedures stated in the standard. While the agency will use those procedures in its compliance testing, the manufacturer may certify compliance with the performance requirements of a standard through engineering studies, computer simulations, mathe matical calculations, or other means intended as an exercise of due care and affording a reasonable basis upon which to certify compliance.

Your final question is:

It is acceptable to set up initial "O" point of S7.7.5.2(a)(2) not mechanically but photometrically?

You may determine the "O" point by whatever means you deem appropriate for the headlighting system, as long as the method achieves a horizontal "O" point that may be used for the purposes of paragraph S7.7.5.2(a)(2), and any other paragraph in which the horizontal "O" mark is required to be determined.

In the future, please address your requests for interpretations of Standard No. 108 to this office.

Sincerely,

ENCLOSURE