Robert Bosch GmbH
Dear Herr Spingler:
We have received your FAX of December 18, 1995, asking whether it is permissible under Motor Vehicle Safety Standard No. 108 "to achieve both high- and lowbeam of a headlamp with only one single light source?" If the answer is yes, you would like to know which photometric requirements are applicable, saying that, in any event, it will meet the photometric requirements of any beam in which it is operated.
Use of a single light source (which we interpret to mean a single replaceable light source with a single filament) to provide both beams is not prohibited. While not specifically identified, it is permissible in either integral beam headlighting systems specified in paragraph S7.4 of Standard No. 108 or replaceable bulb headlighting systems of S7.5. Each such headlamp in a two-headlamp system is required by S7.4(a)(2) to be designed to conform to the photometrics of Figure 17A or Figure 27 for integral beam systems, or either Figure 17A or Figure 27 for replaceable bulb systems, depending on the type of light source used.
If this is a new type of replaceable light source, the relevant information required by Part 564 for such light sources would need to be submitted in advance of its use, in accordance with that regulation.
If you have any questions, you may refer them to Taylor Vinson of this Office.
Samuel J. Dubbin Chief Counsel ref:108 d:1/29/96