Interpretation ID: nht88-1.71

TYPE: INTERPRETATION-NHTSA

DATE: 03/16/88

FROM: AUTHOR UNAVAILABLE; Erika Z. Jones; NHTSA

TO: Koito Mfg. Co. Ltd.

TITLE: FMVSS INTERPRETATION

TEXT:

Mr. M. Iwase Technical Administration Dept. Roito Mfg. Co. Ltd. Shizuoka Works 500, Ritawaki Shimuzi--shi, Shizuoka-ken JAPAN

Dear Mr. Iwase:

This is in reply to your letter of January 25, 1988, with respect to photometric values for stop lamps and taillamps on motorcycles, and the spacing required between them and turn signal lamps.

You have asked two questions with respect to two types of motorcycle rear lighting devices, which you call "Structure 1" and "Structure 2". Although a single lamp located on the vertical centerline may be used to fulfill rear lighting requirements on mot orcycles, each of your Structures features two bulbs, symmetrically placed on each side of the vertical centerline. Each Structure is a single lighting device, featuring a turn signal bulb at each extremity. In Structure 1 a chamber containing a tail/sto p lamp bulb is directly inboard of the chamber containing a turn signal bulb. The two chambers on each side are separated by a central portion of the device which is decorative in nature. Unlike Structure 1, Structure 2 is a three-chamber device, with se parate chambers at each end for the turn signal bulbs, and a central chamber incorporating two tail/stop lamp bulbs.

With respect to each Structure and Motor Vehicle Safety Standard No. 108 you have asked:

"(a) When tail & stop lamp on either side is lighted individually, it shall be satisfied with the photometric values of lighted section "1" which are specified in Figure 1b of S4.1.1.11.

(b) When tail & stop lamp on both sides are lighted together, it shall be satisfied with the photometric values of lighted section "2" which are specified in figure 1b of S4.1.1.11." Figure 1b specifies the minimum and maximum allowable candlepower values for lighting devices with one, two, and three lighted sections. However, the number of lighted sections is calculated with respect to each lamp, not the total number of lighted sect ions used for a specific purpose, or lit at a given time. We consider Structure 1 to comprise two separate tail/stop lamps, each consisting of a single chamber. Similarly, Structure 2 incorporates a single tail/stop lamp consisting of a single chamber in which two bulbs are used. Therefore, for both Structures and for both (a) and (b) the lamp should be designed so that the single chambers meet the photometric values for single compartment lamps.

Your second question for each Structure is whether the specified minimum edge to edge separation distance between turn signals and tail/stop lamps is required. The answer is yes, and the separation distance you have depicted in your drawings appears to c omply with this requirement.

Sincerely,

Erika Z. Jones Chief Counsel

Air-Mail

Ms. Erika Z. Jones Chief Counsel National Highway Traffic Safety Admin. 400 Seventh Street, S.W. Washington, D.C. 20590 U.S.A.

Subject: Tail & Stop Lamp for Motorcycle (1) photometric values (2) Spacing with Turn Signal Lamp

Dear Ms. Erika Z. Jones:

The photometric values which are required for tail & stop lamp for motorcycle are specified in S. 4.1.1.11 of FMVSS No. 108, and minimum spacing between the lamp and turn signal lamp is specified in Table IV.

We would like to ask you the following questions concerning photometric values of tail g stop lamp for motorcycle and minimum spacing between the lamp and turn signal lamp in the cases of Structure-(1) and -(2) which are shown in the attached drawing.

Question-1:

In Structure-(1) and -(2), which of the following cases shall be applied for the photometric values required for tail & stop lamp?

(a) When tail & stop lamp on either side is lighted individually, it shall be satisfied with the photometric values of lighted section "1" which are specified in Figure lb of S. 4.1.1.11.

(b) When tail & stop lamps on both sides are lighted together, it shall be satisfied with the photo-metric values of lighted section "2" which are specified in figure 1b of S. 4.1.1.11.

Attn: Ms. Erika Z. Jones Date: Jan. 25, 1988

Question-2; For each case of Structure-(1) and-(2) as illustrated in the attached sheet, shall the specification of 4 inch minimum spacing between tail & stop lamp and turn signal lamp be required or not:

Upon your review, your prompt reply to this matter would be greatly appreciated.

Very truly yours,

Mr. Iwase Manager Technical Administration Dept. Koito Mfg. Co., Ltd. Shizuoka Works

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