Interpretation ID: NCC-230120-001 571.108 Peterson Trailer Auxiliary Door Light 11.06.24 signed
November 6, 2024
Mr. Donald Lane
Peterson Manufacturing Co.
4200 E. 135th Street Grandview, MO 64030
Dear Mr. Lane:
This responds to your letter, received January 6, 2023, in which you requested a letter of interpretation asking whether a lamp located on the front of a trailer that would illuminate green or red to indicate whether the trailer doors are open or closed is compliant with Federal Motor Vehicle Safety Standard (FMVSS) No. 108, Lamps, reflective devices, and associated equipment. Based on the information you provided in your letter, as explained in more detail below, we have concluded that installing the lights as described would not be permissible under FMVSS No. 108.
In responding to this request, NHTSA notes that the contents of this letter do not have the force and effect of law and are not meant to bind the public in any way. This letter is only intended to provide clarity regarding existing requirements under the law at the time of signature.
Background
NHTSA is authorized by the National Traffic and Motor Vehicle Safety Act (Safety Act, 49 U.S.C. Chapter 301) to issue FMVSS that set performance requirements for new motor vehicles and new items of motor vehicle equipment. The Safety Act requires manufacturers to self-certify that their vehicles and equipment conform to all applicable FMVSS in effect on the date of manufacture. NHTSA also investigates safety-related defects. After first purchase of a vehicle or equipment in good faith other than for resale, section 30122 of the Safety Act requires that a manufacturer, distributor, dealer, rental company, or motor vehicle repair business not knowingly make inoperative any part of a device or element of design installed on or in a motor vehicle or motor vehicle equipment in compliance with an applicable motor vehicle safety standard. This letter represents NHTSA’s opinion concerning whether your design, as you describe it, would be permitted under FMVSS No. 108 and section 30122.
In your letter, you state that you have been asked to install an “auxiliary light” on trailers at or over 2032mm in width and 8.1m in length. The light would be installed on the front of the trailer “so as to be visible to the driver in the driver’s side mirror” and would illuminate green when the trailer doors are shut and red when at least one of the trailer doors are open. Although it is not clear from your description, we assume that the light would also be visible to other individuals looking at the trailer from the front. You also state that you intend for the lamp to only illuminate on the private property of the trailer owner, not on other roads. You ask whether the light could be made with green and red LEDs and clear lenses or in the alternative use green or red lenses.
Requirements of the Standard
FMVSS No. 108 specifies requirements for original and replacement lamps, reflective devices, and associated equipment, including for trailers. For auxiliary lamps, the primary restriction imposed by FMVSS No. 108 is by S6.2.1, which states that “[n]o additional lamp, reflective device, or other motor vehicle equipment is permitted to be installed that impairs the effectiveness of lighting equipment required by this standard.” Both original equipment and aftermarket lighting can run afoul of the “make inoperative” provision, and NHTSA considers the installation of an aftermarket lamp to violate the “make inoperative” provision if the installation of the same lamp as original equipment would violate FMVSS No. 108.1 Therefore, while you do not state in your letter whether your installation would be as original equipment or in the aftermarket, we conduct the same impairment analysis. These prohibitions bar installation by a manufacturer, distributor, dealer, rental company, or motor vehicle repair business of lamps that would impair the effectiveness of required lighting, but do not apply to the owner of a vehicle.
Typically, the impairment determination under FMVSS No. 108 S6.2.1 is made on a case-by- case basis and considers four main characteristics of the auxiliary lamp to analyze whether it impairs the effectiveness of required lighting: the brightness, color, location, and activation pattern of the lamp. This list is not exhaustive and other considerations may be relevant to the analysis. NHTSA has long maintained that highway traffic safety is enhanced by drivers’ familiarity with established lighting schemes, which facilitates their ability to instantly recognize the meaning the lamps convey and respond accordingly. Therefore, NHTSA has interpreted the impairment provision to prohibit auxiliary lamps that are colors and are mounted in locations which are likely to cause confusion to other road users. For auxiliary lamps located on the front of vehicles, these colors include red, which could be confused for a taillamp or stop lamp, and green, which typically conveys the message that one may proceed forward and could therefore impair required lighting that indicates caution.2
1 See, e.g., Letter to Timothy C. Murphy (Nov. 1, 2004), available at
https://www.nhtsa.gov/interpretations/gf006332.
2 See Letter to Paul Schaye (Sept. 9, 2019), available at https://www.nhtsa.gov/interpretations/571108-ama-schaye- front-color-changing-light; See also, Letter to Kerry Legg (Oct. 19), 2006, available at https://www.nhtsa.gov/interpretations/legg1.
For required lighting relevant to your inquiry, FMVSS No. 108 requires that all trailers have two red taillamps and two red stop lamps on the rear of the trailer, at the same height, symmetrically about the vertical centerline, and as far apart as practicable. Also, all trailers of 2032 mm or more in width must have three red identification lamps on the rear, at the same height as one another, as close to the top of the trailer as practicable and as close as practicable to the vertical centerline of the trailer, with lamp centers spaced not less than 6 inches or more than 12 inches apart. Additionally, such trailers must also have two amber clearance lamps on the front and two red clearance lamps on the rear, symmetrically mounted about the vertical centerline as near the top as practicable to indicate the overall width of the trailer.3
Discussion
We now turn to your inquiry. As an initial matter, it is immaterial to this analysis that the lamp is intended to illuminate only on the trailer owners’ property. NHTSA’s longstanding position is that when the vehicle is designed to be used on-road, its equipment must meet all applicable FMVSS.4
Your lamp is not required equipment and so would be considered, as you correctly describe it, as auxiliary or supplemental lighting. Therefore, we turn to the question of impairment and look to the relevant characteristics.5 The factors most relevant to your inquiry are the location and color of the lamps, which we analyze together. We find that the lamp design described in your letter is likely to impair the effectiveness of the identification and clearance lamps required by FMVSS No. 108, and, if installed by you or another entity subject to the “make inoperative” prohibition as aftermarket equipment, would impair the effectiveness of that required lighting installed in compliance with FMVSS No. 108.
By requiring different colored lamps on the front and the rear of trailers, FMVSS No. 108 facilitates rapid recognition by road users of the direction that a trailer is facing or is moving. Because your device illuminates red in the front of the trailer, it operates contrary to this standard’s intention. This lighting arrangement could cause drivers to mistake the front of the trailer for the rear. Such a mistake, even if only for a moment, may cause drivers to take unnecessary, and possibly unsafe, driving maneuvers or to fail to take other maneuvers in time to
3 FMVSS No. 108 Table I-a.
4 See Letter to Paul Crunk (Aug. 11, 2000), available at https://www.nhtsa.gov/interpretations/21872ztv.
5 Regarding activation pattern, NHTSA interprets FMVSS No. 108 to require that all auxiliary lamps be “steady burning,” with the sole exception being auxiliary lamps that supplement required lamps that flash, such as turn signals. For the purposes of this letter, we assume the lamps you describe would be steady burning when activated.
Before 2007, FMVSS No. 108 included an explicit requirement that, with the exception of certain types of required lamps (e.g., turn signal lamps), all lamps on a vehicle, including auxiliary lamps, must be steady burning. In 2007, NHTSA implemented an administrative reorganization of FMVSS No. 108 which, among other things, converted the blanket “steady burning” requirement (and its exceptions) into individual activation requirements for each type of required lamp. See 72 FR 68234 (Dec. 4, 2007). Although the reorganized rule no longer includes a blanket “steady burning” requirement, NHTSA stated in the preamble to the reorganized rule that its “rewrite of FMVSS No. 108 is considered administrative in nature because the standard’s existing requirements and obligations are not being increased, decreased, or substantively modified.” Moreover, NHTSA continues to believe that flashing auxiliary lamps would impair the effectiveness of required lamps by distracting or confusing other road users.
prevent dangerous events. Therefore, it would impair the effectiveness of the identification and clearance lamps required on trailers. Additionally, when the device is activated green, it may give the misimpression to road users that it is safe to proceed forward when in fact it may not be safe to do so, which would impair the effectiveness of various required lamps intended to communicate caution, such as stop lamps. Our opinion is the same regardless of whether the light uses green or red colored light sources or colored lenses.
We hope you find this information helpful. If you have further questions, please contact Eli Wachtel of my staff at (202) 366-2992.
Sincerely,
Adam Raviv
Chief Counsel
Dated: 11/6/24
Ref: Standard No. 108