Interpretation ID: nht92-5.29

DATE: July 7, 1992

FROM: Paul Jackson Rice -- Chief Counsel, NHTSA

TO: Guy Dorleans -- International Regulatory Affairs Manager, Valeo

TITLE: None

ATTACHMT: Attached to letter dated 5/25/92 from Guy Dorleans to Chief Counsel, NHTSA

TEXT:

This responds to your letter of May 25, 1992, asking for confirmation that your interpretation of Motor Vehicle Safety Standard No. 108 is correct.

As you state, "Standard No. 108 specifies different levels of photometric requirements for signal lamps, depending on the number of lighted sections which they have", whether there are one, two, or three such sections (see Figure 1b). You further state that "the use of light-emitting diodes does not permit to distinguish at a glance several distinct lighted sections." Thus, when a single diode fails, "a variation will be easy to identify." Where "light-emitting diodes . . . are used in quantities bigger than three, we consider that the provision for 'lamps with three lighted sections' applies a fortiori, because its severeness will keep the user on the safe side, even though the standard does not specifically address the problems raised by the multiple light sources."

Standard No. 108 incorporates by reference two different SAE standards for turn signal lamps, J1395 APR85 for vehicles 2032mm or more in overall width, and J584 NOV84 for narrower vehicles. SAE J1395 establishes luminous intensity minima and maxima photometric requirements without reference to either compartments or lighted sections, and all that is required is for the lamp to comply at the individual test points specified. Section S5.1.1.31 clarifies that measurements of a multiple compartment turn signal lamps on vehicles to which SAE J1395 APR85 applies are to be made for the entire lamp and not for the individual compartments.

However, SAE J584 NOV84 continues to specify different minimum photometric requirements for one, two, and three "lighted sections." Because the SAE does not prescribe photometric requirements for more than three lighted sections, we have concluded that any device that contains more than three lighted sections need only comply with the requirements prescribed for three lighted sections.