Interpretation ID: 19845.ztv

Mr. P. Binder
Valeo Deutschland
Stuttgarter Strasse 119
74321 Bietigheim-Bissingen
Germany

Dear Herr Binder:

This responds to your fax of April 12, 1999, to Taylor Vinson of this Office, asking for an interpretation of Federal Motor Vehicle Safety Standard No. 108.

On August 2, 1994, we addressed your rear motor vehicle lighting array. Sketch 1 in your new letter depicts that lighting array: a stop lamp, turn signal lamp, taillamp, and reflex reflector mounted on the car body and, immediately adjacent on the tailgate, a backup lamp, fog lamp, taillamp, and reflex reflector. You were concerned with requirements for the taillamp system, and we confirmed your interpretation that the combination of taillamp 1 and taillamp 2 could be used to meet the photometric requirements for two lighted sections.

You now ask whether that interpretation also applies to a new taillamp design (Sketch 2) that will be used to replace the old design (Sketch 1). In this design, the taillamp portion of Sketch 1 lamp array appears to have been replaced with light guides and light-emitting diodes (LEDs). Our interpretation does not apply to your new taillamp design. Because more than two LEDs are used (i.e., more than two light sources), the lamp must meet the photometric requirements for three lighted sections.

The fundamental difference between the old and new systems is that each lighted section of the lamps in Sketch 1 contains a single light source whereas the taillamps in Sketch 2 require more than one light source to achieve compliance with the photometric performance required of a single lighted section. Thus, a lamp using three or more light sources must meet the photometry of a three-compartment lamps.

You asked about additional regulations. We have proposed that lamps with LEDs be designed to conform to photometric requirements based on the dimension of the effective projected luminous lens area for the function being tested (63 FR 34350 at 34356, June 24, 1998). A lamp is regarded as having one lighted section if the maximum horizontal or vertical linear dimension of the effective projected luminous lens area of the lamp is less than 150 mm, two lighted sections if the dimension is 150-300 mm, and three lighted sections if the dimension is greater than 300 mm. We have not yet made a decision concerning a final rule. Some commenters have expressed significant concerns that this proposal is wrong. We are evaluating these comments. In the meantime, you should not design future lamps on the assumption that NHTSA will adopt the proposal.

If you have further questions, please contact Mr. Vinson (FAX 202-366-3820).

Sincerely,
Frank Seales, Jr.
Chief Counsel
ref:108
d.7/7/99