Interpretation ID: 21406.ztv

Herr Tilman Spingler
Automotive Lighting Reutlingen GmbH
Tubinger Strasse 123
72762 Reutlingen
Germany

Dear Herr Spingler:

This is in reply to your fax of March 16, 2000, asking for an interpretation of S7.8.5.3 of Federal Motor Vehicle Safety Standard No. 108, Lamps, Reflective Devices and Associated Equipment.

Paragraph S7.8.5.3 specifies requirements for headlamp visual/optical aiming. You note that this paragraph "does not say anything about the measuring distance and the diameter of the photocell to be used when measuring the cut-off for determination of position and quality of the cut-off." You state that the preamble to the final rule adopting S7.8.5.3 mentions a GTB document in which "a measuring distance of 10m and a diameter of the photocell has been proposed." According to your letter, the rationale behind the proposals was that visual aiming, where ever conducted in Europe be done at a 10m distance, "and the instrumental method developed for FMVSS 108 should reflect the 'real world' of visual aiming at that time."

Your question, then, is whether it is permissible for a headlamp manufacturer to "measure the cut-off at 10m with a 10mm photocell for aiming purposes and then measure the light intensity of the correctly aimed headlamp at equal or more than 18.3m. We confirm that this is permissible for the reason indicated below.

Paragraph S7.8.5.3 was adopted pursuant to a negotiated rulemaking in which the attending parties concurred in the drafting and adoption of the language of the preamble and the resulting rule. Although the 10m distance and diameter of the measuring photocell were not incorporated into Standard No. 108, there was unanimous agreement as to this basis for specifying the measuring procedures. The text to which you refer appears at 62 FR 10710 (March 10, 1997). We noted in this preamble (p. 10711) that a procedure had been developed which provided a baseline system for the visual aim test. The procedure was developed by the Groupe de Travail "Bruxelles 1952" (GTB) Short-term Scientific Studies Working Group (SSST WG), and set forth in "Draft minutes of the Meeting held at Budapest 1995 October 3," which is filed in our rulemaking docket as attachment 3-9 to the Committee's minutes of Meeting No. 3. This procedure specifies that the cut-off is to be measured at a distance of 10m using a photocell with an aperture of 10mm. This was understood by all the parties to the negotiated rulemaking, and we intend to include it in the text of Standard No. 108 itself in a future amendment.

In summary, a headlamp with a cut-off feature should be measured and aimed at 10m using a 10mm photocell, and its compliance with photometric requirements determined at 18.3m.

If you have any questions, you may contact Taylor Vinson of this Office (fax 202-366-3820).

Sincerely,
Frank Seales, Jr.
Chief Counsel
ref:108
d.4/6/2000