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Interpretation ID: Bailes.1

    Mr. Alistair Bailes
    Perei Group Ltd.
    Sunbury House
    Ivy Road
    Aldershot
    GU12 4TX
    United Kingdom


    Dear Mr. Bailes:

    This responds to your letter, in which you seek confirmation as to whether your proposed front turn signal lamp would meet the requirements of Federal Motor Vehicle Safety Standard (FMVSS) No. 108, Lamps, Reflective Devices, and Associated Equipment. You also asked whether your proposed lower beam headlamps visual/optical aiming mechanism would meet the standards requirements. We are pleased to have the opportunity to explain the relevant requirements of our standard.

    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 (see 49 U.S.C. Chapter 301). NHTSA does not provide approvals of motor vehicles or motor vehicle equipment. Instead, manufacturers are required to self-certify that their products conform to all applicable safety standards that are in effect on the date of manufacture. FMVSS No. 108 specifies requirements for original and replacement lamps, reflective devices, and associated equipment. The following represents our opinion based on the facts set forth in your letter.

    Your letter described and depicted your proposed vehicle frontal lighting system as having a turn signal with a single reflector illuminated by a PY21W filament bulb. According to your letter, the housing containing the turn signal has two lenses, a primary lens (with an area of over 22 cm 2) and a smaller secondary lens which emits light but does so in a manner that is "superfluous to the performance and is primarily an aesthetic embellishment".(Looking at the exterior of the vehicle, the two lenses have the appearance of two separate lamps with a small amount of space between them.)You stated, however, that this second lens is necessary to meet European requirements that the turn signal be 400 mm or less from the extreme outer edge of the vehicle. In your letter, you asked whether this proposed design would comply with FMVSS No. 108.

    Furthermore, your letter shows a pair of headlamps with two separate adjustment mechanisms for the lower beam. You described the system as having visual/optical aiming, with two adjustment mechanisms: (1) a vertical/horizontal adjustment and (2) a horizontal adjustment. Your letter stated that vertical aim is adjusted by rotating the vertical/horizontal adjustment, and horizontal aim is adjusted by rotating both adjustments. According to your letter, the system is not equipped with a vehicle headlamp aiming device (VHAD). In your letter, you asked whether this proposed design would comply with FMVSS No. 108 or whether a VHAD would be required. Alternatively, you asked whether compliance could be achieved by disabling or removing the horizontal adjustment, but while retaining the vertical adjustment.

    FMVSS No. 108 sets forth requirements for turn signals (see S5.1) and their location (see S5.3) on a vehicle, as contained in Tables I-IV of the standard. (We note that although these tables distinguish between vehicles less than 80 inches (2032 mm) in width and those greater than 80 inches (2032 mm) in width, the requirements for the number and location of turn signals are essentially the same for the purposes of the present analysis.)For front turn signal lamps, the standard requires the vehicle manufacturer to install one amber lamp at or near the front of the vehicle on each side of the vertical centerline, at the same height, as far apart as practicable.

    In paragraph S5.3.2(b)(1), the standard states, "When a vehicle is equipped with any lamp listed in Figure 19 of this standard [including front turn signal lamps], each such lamp must provide not less than 12.5 square centimeters of unobstructed effective projected luminous lens area in any direction throughout the pattern defined by the corner points specified in Figure 19 for each such lamp".Paragraph S5.3.1.7 of the standard further provides, "On a motor vehicle on which the front turn signal lamp is less than 100 mm from the lighted edge of a lower beam headlamp, as measured from the optical center of the turn signal lamp, the multiplier applied to obtain the required minimum luminous intensities shall be 2.5".

    While we cannot provide a determination as to whether your proposed frontal lighting system would comply with FMVSS No. 108, we can offer certain observations based upon the photograph accompanying your letter. It appears that the front turn signal is amber, as required under the standard, and its location in the assembly suggests that it is capable of being mounted at or near the front of the vehicle on each side of the vertical centerline, at the same height, as far apart as practicable. Your letter states that the primary lens has an area greater than 22 square centimeters, which is the minimum size for front turn signal lenses on passenger cars required by the standard (see S5.1.1 and SAE J588 Nov. 1984). Further, you must ensure that the lamps effective projected luminous lens area would meet the standards visibility requirement of at least 12.5 square centimeters, as installed with all obstructions considered. Alternatively, you could design this lamp to conform to the visibility requirements specified in S5.3.2(b)(2).

    We would bring two matters to your attention. First, if our understanding of your photograph is correct, this lamp would be mounted on the drivers side of the vehicle, in which case it appears that the upper beam is more outboard than the lower beam. However, Standard No. 108 requires the lower beam to be at a more outboard location, relative to the upper beam. Unless your photograph is mislabeled, your proposed design would apparently not meet that requirement.

    Second, the standard necessitates that careful attention be paid to the spacing between the turn signal and the lower beam headlamp. Again, if this turn signal lamp is located less than 100 mm from the lighted edge of a lower beam headlamp, as measured from the optical center of the turn signal lamp, paragraph S5.3.1.7 requires the intensity of the turn signal to be multiplied by 2.5. Assuming for the sake of argument that the above issue related to upper/lower beam location is resolved and presuming that the primary lens meets all other requirements for a turn signal under FMVSS No. 108, we do not believe that the presence of a separate and discrete embellishment provided by the secondary lens would violate S5.3.1.7, because the turn signal provided by the primary lens would meet the requirements of the standard without being masked by the headlamp. Furthermore, we have no reason to believe that the illumination provided by the secondary lens would impair the vehicles required lighting equipment.

    As to the issue of the horizontal aim of the lower beam headlamp, paragraph S7.8.5.3(b), Horizontal aim, lower beam, of FMVSS No. 108 provides, "There shall be no adjustment of horizontal aim unless the headlamp is equipped with a horizontal VHAD. If the headlamp has a VHAD, it shall be set to zero".In the 1997 final rule amending Standard No. 108 to permit headlamps that are visually or optically aimed, the agency adopted this requirement for horizontal aim to either be fixed and nonadjustable, or have a horizontal VHAD, because the lower beam would not have any visual cues for achieving correct horizontal aim, and it would not be possible to add such visual features without damaging the beam pattern (see 62 FR 10710, 10712 (March 10, 1997)). Visual/optical aim headlamps became part of FMVSS No. 108, but they were required to meet new beam pattern photometric requirements, with a beam pattern relatively insensitive to modest horizontal misaim.

    In 1999, Federal-Mogul Lighting Products (Federal-Mogul) petitioned the agency for rulemaking to amend FMVSS No. 108 to allow visually/optically aimed headlamps to have a horizontal adjuster system that does not have the required 2.5-degree horizontal adjustment range or a VHAD indicator, as required by the standard. As we noted in our denial of Federal-Moguls petition, our 1997 final rule permitted visual/optical aim headlamps, based upon comments to the agency stating that vehicles could be built with such close tolerances that no horizontal aim adjustment would be necessary, and we noted that no useful visual cue for horizontal aiming exists (see 66 FR 42985, 42986 (August 16, 2001)). Because no visual cue was available for the purpose of horizontal aiming, the agency did not permit any horizontal movement of such headlamps, with the lamp essentially being correctly aimed as installed. As an alternative, horizontal-aiming VHADs were permitted (but not required) on visual/optical aiming headlamps as a means for manufacturers to meet European requirements for both a horizontal and vertical aim adjustment, but that the horizontal VHAD must be set to zero.

    Because visual/optical aim headlamps do not currently have any feature that would allow anyone other than the headlamps manufacturer to objectively assess the accuracy of horizontal aim, a vehicle manufacturer seeking to adjust the horizontal aim of these lamps on a new vehicle would have no objective, repeatable way to assess the impact of its horizontal aim adjustments on real world lighting performance. Because of this limitation, neither the agency nor anyone else, including vehicle dealers and State safety inspectors, could assure correct headlamp aim. As stated in our denial of Federal-Moguls petition, we believe that it is incumbent upon the industry to develop a single method for horizontal aiming that could be incorporated into FMVSS No. 108, and we will not assess individual manufacturers petitions for alternatives to installation of a horizontal VHAD.

    In light of the limitations that the standard places upon horizontal aiming of visual/optical aim headlamps, your proposed design, as presented, would not comply with the relevant requirements of Standard No. 108. The standard does not permit a horizontal adjustment mechanism for the lower beams of such headlamps, unless it is a VHAD that is set to zero.

    Furthermore, we do not believe that elimination of the "horizontal adjustment (2)", as depicted in the diagram accompanying your letter, would suffice to remedy this. Your suggestion to remove the horizontal adjustment and "have only vertical adjustment" would apparently not meet the requirement of the standard, because the remaining adjustment is presented as a "vertical/horizontal adjustment (1)" and the letter states that horizontal aim is adjusted by rotating both adjustments. Thus, elimination of adjustment (2) would nevertheless appear to leave horizontal aim adjustment capability as part of adjustment (1), which is not permitted under the standard.

    If you have any further questions, you may call Mr. Eric Stas of my staff at (202) 366-2992.

    Sincerely,

    Stephen P. Wood
    Acting Chief Counsel

    ref:108
    d.11/4/05