Interpretation ID: 17497.ztv

Herr Tilman Spingler
Robert Bosch GmbH
FAX 9-011-49-7121-35-1792

Dear Herr Spingler:

This is in reply to your fax of March 12, 1998, commenting on our letter to you of March 10 with respect to the visual/optical headlamp aiming provisions of Federal Motor Vehicle Safety Standard No. 108.

In response to your question, our letter advised that it would not be permissible to install on new vehicles a mixed headlighting system in which a headlamp on one side of the vehicle would have a VHAD for vertical aim and on the opposite side a visually aimable headlamp. We also advised that the VHAD appeared to allow for vertical aim only and did not include a horizontal aiming feature. You comment that it was not the intent to have a headlamp with only a vertical VHAD but "to replace the vertical VHAD (bubble level) by means which allow optical/visual aim and to leave the horizontal VHAD as it is." We understand from your remark that both headlamps would have a horizontal VHAD and that one would have a vertical VHAD as well while the other would substitute for the vertical VHAD a means allowing optical/visual aim. This clarification, then, moots our previous comment.

You have also commented that "mixed installation should only be permitted in the case of replacement of a damaged headlamp as indicated in my FAX of 1/14/98," and asked whether our advice that the headlamps on both sides of a new vehicle have to be identical "really only applicable for new vehicles."

We do not seem to have received your FAX of January 14, 1998, in which you indicated that your question pertained to replacement headlamps rather than original equipment. While the prohibition against mixed headlamp aiming systems that was the subject of the March 10 interpretation applies only to new vehicles, the agency is concerned that the ability to correctly aim all headlamps on a vehicle could be lost as a result of certain mixes of replacement headlamps. Accordingly, the agency expects to propose shortly rulemaking that will address this issue.

Sincerely,
Frank Seales, Jr.
Chief Counsel
ref:108
d.6/3/98