Interpretation ID: nht88-1.72

TYPE: INTERPRETATION-NHTSA

DATE: 03/16/88

FROM: AUTHOR UNAVAILABLE; Erika Z. Jones; NHTSA

TO: C.I. Nielsen -- Vice President, General Sales Manager, Wesbar Corporation

TITLE: FMVSS INTERPRETATION

TEXT:

Mr. C. I. Nielsen Vice President General Sales Manager Wesbar Corporation P.O. BOX 577 West Bend, WI 53095

This is in reply to your letter of February 17, 1988, asking for an interpretation of paragraph S4.1.1.7 of Motor Vehicle Safety Standard No. 108, which applies to turn signal lamps. In pertinent part this section requires turn signal lamps for vehicles whose overall width is 80 inches or more to "have an effective projected luminous area not less than 12 square inches." Your design has a lens area of 12 square inches incorporating an integral Class A reflex reflector, and you have asked whether you may include the "illuminated (by the turn signal bulb) reflex reflector portion of the turn signal lens" in your calculation.

We assume from your letter that the light shines through the reflector when the turn signal is activated, and that the reflector is not opaque. In this instance, the reflector area may be included as part of "the effective projected luminous area" within the meaning of S4.1.1.7.

I hope that this answers your question.

Sincerely,

Erika Z. Jones Chief Counsel

February 17, 1988

Ms. Erika Jones, Chief Counsel-DOT Room 5219 NASSIf Building 400 7th Street, Southwest Washington, DC 20590

SUBJECT: REQUEST FOR COMPLIANCE INTERPRETATION 54.1.1.7

Dear Ms. Jones:

We are writing to you for clarification of 54.1.1.7 of FMVSS 108. Our request involves turn signal lamps on trailers 80-inches or more in width and, practically speaking, centers around the wording "shall have an effective project luminous area not less than 12 square inches".

Our design calls for a multifunction lens of 12 square inches, which incorporates an integral Class A reflex reflector. QUESTION: When the turn lamp is activated, may we include, for the square inch calculation, the illuminated (by the turn signal bulb) reflex reflector portion of the turn signal lens: We know we are allowed to optically combine two, or more, functions (except for the tail light with the clearance light function), therefore, we don't see this concept as the hurdle. Instead, we find the question lying with the definition of "effective projected luminous area".

Thank you for looking into this matter, Ms. Jones, and we look forward to receiving your written interpretation on the "effective projected luminous area".

Respectfully,

WESBAR CORPORATION

C.I. NIELSON III Vice President General Sales Manager

CIN:mm cc: J. Karrenbauer S. Johnston A. Cunningham DOT

(SEE ATTACHMENT...)