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Interpretation ID: Koito.2

    Mr. Takayuki Amma
    Manager, Regulations & Certification
    Koito Manufacturing Co., Ltd.
    4-8-3, Takanawa
    Minato-ku Tokyo
    Japan


    Dear Mr. Amma:

    This responds to your recent letter, in which you asked whether it would be permissible under Federal Motor Vehicle Safety Standard (FMVSS) No. 108, Lamps, Reflective Devices, and Associated Equipment, to manufacture and sell a headlamp that automatically reduces intensity when the vehicle is stopped. Your letter stated that the lamp (which includes a fail-safe performance feature) would operate at full intensity when the vehicle is in forward motion, but that an electronic light source control gear would reduce the intensity once the vehicle comes to a rest. According to your letter, "[a]t all times through the change of the intensity, the lamps provide sufficient level of intensity and will be within the parameters of the minimum and maximum values of candela specified in FMVSS No. 108," and you further suggested that such headlamps would have the potential for significant energy conservation (about a 20-40% reduction in wattage), depending upon the optical design of the headlamps. As discussed below, we believe that the intensity-reducing headlamps described in your letter would not be permissible under FMVSS No. 108, because the would not meet the "steady-burning" requirement of S5.5.10.

    By way of background, the National Highway Traffic Safety Administration (NHTSA) is authorized to issue FMVSSs that set performance requirements for new motor vehicles and items of motor vehicle equipment. It is the responsibility of manufacturers to certify that their products conform to all applicable safety standards before they can be offered for sale (see 49 CFR Part 571). After the first sale of the vehicle, manufacturers, distributors, dealers, and repair businesses are prohibited from "knowingly making inoperative" any device or element of design installed on or in a motor vehicle in compliance with an applicable standard.49 U.S.C. 30122.

    As you are aware, the requirements for lighting equipment are contained in FMVSS No. 108, which provides in relevant part:

    S5.5.10 The wiring requirements for lighting equipment in use are:
    (a) Turn signal lamps, hazard warning signal lamps, and school bus warning lamps shall be wired to flash;
    (b) Headlamps and side marker lamps may be wired to flash for signaling purposes;
    (c) A motorcycle headlamp may be wired to allow either its upper beam or its lower beam, but not both, to modulate from a higher intensity to a lower intensity in accordance with section S5.6;
    (d) All other lamps shall be wired to be steady-burning.

    In short, S5.5.10(d) of FMVSS No. 108 requires that all lamps must be "steady burning," unless otherwise permitted, and while S5.5.10(b) does permit headlamps to be wired to flash for signaling purposes, we note that paragraph S3 of FMVSS No. 108 defines "flash" as meaning "a cycle of activation and deactivation of a lamp by automatic means."

    Your proposed headlamp would not fall within any of the standards express exceptions, and therefore, must be "steady-burning." Through our interpretations, we have explained that the "steady-burning" requirement under the standard means "a light that is essentially unvarying in intensity" (see e.g., February 9, 1982, letter of interpretation to Dr. H.A. Kendall). However, as stated in your letter, your proposed headlamp would routinely experience perceptible intensity changes resulting in a 20-40% reduction in wattage, so the lamp would not meet above definition of "steady-burning."

    There are several reasons for the requirement for headlamps to be steady-burning. For example, several States have expressed concern that lights of variable intensity could be confused with emergency vehicles, which are allowed to have flashing headlamps. We also note that motorcycle headlamp modulation, while permitted under S5.5.10(c), must meet the requirements of S7.9.4; the modulation rate is regulated to prevent seizures in susceptible individuals. Furthermore, we believe that motor vehicle safety is best promoted by standardization of lighting signals.

    In your letter, you pointed to our July 21, 1998, letter of interpretation to Mr. Ian Goldstein in support of your position that Standard No. 108 should permit headlamps that reduce intensity when stopped. The letter to Mr. Goldstein discussed "gradational" daytime running lamps (DRLs), devices that are capable of modulating the intensity of the DRLs according to ambient light conditions. You quoted from the portion of that letter which provides, "The standard does not prohibit changes in intensity, which we presume will be within the parameters of the minimum and maximum values of candela specified".However, your letter omitted the immediately preceding sentence, which provided, "A DRL with a gradational feature would continue to provide the steady-burning light that is required for DRLs".

    The situation presented in your letter is distinguishable from the one presented in our letter to Mr. Goldstein. In the case of gradational DRLs, the lamps would be expected to determine an appropriate level of intensity based upon ambient lighting conditions and then maintain that level until conditions had changed sufficiently to potentially warrant a further change in intensity. In that case, intensity changes would be expected to occur infrequently and could occur gradually, such that the change would not be perceptible to oncoming drivers.

    In contrast to gradational DRLs, the changes in intensity that would accompany your proposed headlamp design would be anticipated to result in frequent modulation, particularly during instances of stop-and-go city driving. Assuming that the intensity change is perceptible, we believe that such a design could be a source of distraction to other drivers, which could have negative consequences for safety. Accordingly, we believe that the headlamp design presented in your letter would not meet the requirements of S5.5.10 of FMVSS No. 108.

    If you have further questions, please feel free to contact Eric Stas of my staff at this address or by telephone at (202) 366-2992.

    Sincerely,

    Jacqueline Glassman
    Chief Counsel

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