Interpretation ID: 2349y

Mr. T. Chikada Manager, Automotive Lighting Engineering Control Dept. Stanley Electric Co., Ltd. 2-9-13, Nakameguro, Meguro-ku Tokyo 153, Japan

Re: Decorative Supplemental Lighting Devices Not Specified by Standard l08 (Motorcycles)

Dear Mr. Chikada:

This is in reply to your letter with respect to two types of decorative lighting devices intended for installation "on the rear face, and at the top of optional motorcycle rear trunks respectively." I regret the delay in responding.

Type A and Type B would be installed on the same motorcycle. Type A would be installed at the top of the trunk. It consists of an elongated device, illuminated by LEDs when the taillamp is on. Type B is installed on the motorcycle itself. It is a rectangular device, illuminated by an incandescent bulb, which is mounted on the vertical centerline and is flanked by the tail and stop lamps. The distance between the center of the light sources on the two devices is 290mm. (approximately ll 1/2 inches). Both devices emit red light, and their maximum intensity is less than the minimum intensity of the taillamp.

You have asked whether it is permitted to equip a motorcycle with the Type A and Type B accessory lamps. If the answer is affirmative, you have asked whether an LED could be used as the light source for Type B. You have also asked whether the maximum intensity of each device separately should be less than the minimum intensity of the tail lamp, or whether the combined maximum intensity of both devices should be less than the minimum intensity of the tail lamp.

Paragraph S5.1.3 of Federal Motor Vehicle Safety Standard No. l08 (formerly S4.1.3) permits the installation of these lamps if they do not impair the effectiveness of the lighting equipment required by the standard. In this instance, the question to be asked is whether the devices, activated with the taillamps, impair the effectiveness of the taillamps, or the stop lamps. The devices are, in effect, supplemental taillamps, and as such, arguably do not appear to impair the effectiveness of the taillamps required by the standard no matter what their intensity is.

The diagram of Type B indicates that the stop lamps and taillamps are in the same compartment, presumably incorporating a dual filament bulb. Although the stop lamps when activated are brighter than the taillamps, their proximity to the supplemental devices Type A and Type B, each of which are emitting a red light, leads to the possibility that the stop signal would not be as effective as it would be were there no other red lights in the vicinity, and hence impaired within the meaning of S5.1.3. A stop signal must be instantly perceived so that a following driver may determine appropriate action to take. However, we note that this configuration is similar to other stop/taillamp configurations on many vehicles in use on the highways. This would indicate that such configurations do not result in impairment. Thus, the answer to your first question is that both Types of devices are permitted under the standard.

Your second question is whether LEDs are acceptable light sources for Type B. Since there is no restriction on light sources for a lighting device not required by Standard No. l08, you may use the LEDs as light sources.

Your third question is whether the maximum intensity of Type A and Type B, separately, should be less than the minimum intensity of the taillamp. Even though Type A and Type B are optional devices, in the configuration depicted where Type B is immediately flanked on both sides by a taillamp, the appearance of the three lamps would be that of a multicompartment lamp, even though they may actually be separate. To help assure that impairment of either the taillamp or stop lamp does not occur, the intensity of Type B should be identical with that of the taillamps. Otherwise, observers may assume that Type B (which you intend to have an intensity less than a taillamp) is actually the taillamp, and the actual taillamps (which you intend to have an intensity greater than Type B) might appear to be stop lamps that are continually on. This would be deemed impairment since there would be three intensity levels, increasing the possibility of confusion of the intent of the lamps.

As for Type A, its vertical separation decreases the possibility for confusion. If the light sources are LEDs, the color would be a different shade of red that the stop and taillamps. Thus, the intensity is less important. However, it functions as an auxiliary taillamp and should be within the same intensity range as the original equipment taillamps. Finally, you asked whether the combined maximum intensity of both devices would be less than the minimum intensity of the taillamps. Again, this would create three levels of intensity, and could cause confusion in understanding the intent of the lamps. As noted above, the individual intensities should be similar to the intensity of the taillamps.

I hope that this answers your questions.

Sincerely,

Stephen P. Wood Acting Chief Counsel

/ ref:l08 d:3/20/90