Interpretation ID: nht70-2.31

DATE: 10/23/70

FROM: AUTHOR UNAVAILABLE; R. H. Compton; NHTSA

TO: American Motors Corporation

TITLE: FMVSS INTERPRETATION

TEXT: This is in reply to your letter of October 12, 1976, to Mr. Charles A. Baker of this office in which you requested an interpretation of the phrase "affective projected illuminated area."

Class A turn signal lamps are required by Section S3.1 of Federal Motor Vehicle Safety Standard No. 108, which references SAE Standard J588d in Tables I and III for there lamps. The requirements for the illuminated area of a turn signal lamp are specified in J588d as follows:

"The effective projected illuminated area measured on a plane at right angles to the side of the lamp must not be less than 12 sq. in. for Class A and 36 sq/ in. for Class B."

In the 45 degree visibility requirements, this standard further states "To be considered Visible, the lamp must provide an instructed projected illuminated area of outer less surface, excluding reflex, . . .".

Our interpretation of affective projected illuminated area follows; The affective projected illuminated area is that area of the lent measured on a plane as that angles to the axis of the lamp, excluding reflex reflector, noted is not obstructed by an opaque object such as a mounting(Illegible Words)

The above interpretation allows the area of rings or other configurations ((Illegible Word) portions) applied in the lane to be considered part of the total effective from, even if this area does not contribute significantly to the total light output.