Interpretation ID: nht94-3.22

TYPE: INTERPRETATION-NHTSA

DATE: June 6, 1994

FROM: John Womack -- Acting Chief Counsel, NHTSA

TO: M. Guy Dorleans -- Valeo Vision

TITLE: None

ATTACHMT: Attached To Letter Dated 4/20/94 From Guy Dorleans To Mike Perel

TEXT: Dear M. Dorleans:

This responds to your FAX of April 20, 1994, to Mike Perel of this agency, asking for an interpretation of Standard No. 108.

The drawing in your letter depicts a four-lamp headlamp arrangement in which the outermost lamps (lower beam) incorporate HB4 light sources, and the innermost lamps (upper beam), HB3 light sources. In operation, the outermost lamps alone provide the low er beam. However, when the upper beam switch is thrown, all lamps are energized. You ask for confirmation of your interpretation that "outer unit must fulfill table 15a for Low Beam, an (sic) also that inner must fulfill with HB3 alone table 15a High B eam."

Paragraph S7.5 of Standard No. 108 specifies requirements for four-lamp replaceable bulb headlamp systems such as the one you describe. The photometrics that apply to such systems are set forth in paragraph S7.5(b): "The photometrics as specified in sub paragraphs (c) through (e) of this paragraph (depicted in Figure 26) . . . ." Because subparagraph (d) applies to a headlamp equipped with dual filament replaceable light sources and Types HB3 and HB4 are single filament sources, the applicable subparagr aph is (e), and, more specifically, the four-headlamp specifications of (e)(3).

This will confirm your understanding. Under S7.5(e)(3), the lower beam is to be produced by the outermost lamps and designed to conform to the lower beam requirements of Figure 15; the upper beam by the innermost lamps and designed to conform to the upp er beam requirements of Figure 15. This is confirmed in Figure 26. However, the photometrics of Figure 15A will apply on and after September 1, 1994, (Paragraph S7.1).

2

Simultaneous activation of both upper and lower beams is permitted by S5.5.8 of Standard No. 108 for headlighting systems designed to conform to Figure 15. Later this year, we will amend Standard No. 108 to substitute Figure 15A for Figure 15, effective September 1, 1994.

Sincerely,