Skip to main content
Search Interpretations

Interpretation ID: 571-108--backup lamps of truck tractor cab--Daimler Trucks





Mr. Mark Siddall

Senior Team Leader

Product Compliance and Regulatory Affairs

Daimler Trucks North America LLC

4747 North Channel Avenue

Portland, Oregon  97217-7699


Dear Mr. Siddall:


This is in response to your letter received October 24, 2011 inquiring if backup lamps located on the back wall of the truck tractor cab or sleeper rather than at the standard location, the end of the vehicle, would comply with Federal Motor Vehicle Safety Standard  No. 108, Lamps, Reflective Devices, and Associated Equipment (FMVSS No. 108).  Based on the information you have provided, the placement you describe is not on the rear within the meaning of FMVSS No. 108, and therefore does not comply with our requirements for backup lamps.  We address this question in more detail below.


By way of background, the National Highway Traffic Safety Administration (NHTSA) is authorized to issue Federal motor vehicle safety standards 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 approval of motor vehicles or motor vehicle equipment, and we do not determine compliance of a vehicle or item of motor vehicle equipment outside the context of an actual enforcement proceeding.  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.  The following represents our opinion regarding the applicability of our regulations to your proposed lamp placement based upon the facts set forth in the materials that you submitted.


In your letter, you ask if mounting backup lamps on the back wall of a cab or sleeper rather than at the end of the vehicle with the stop lamps and taillamps would meet the requirement contained in FMVSS No. 108 that backup lamps be placed on the rear of the vehicle.  You further state that your proposed configuration would meet the visibility requirements contained in Table V-a of FMVSS No. 108.


The requirements for backup lamps are located at paragraph S7.6 of FMVSS No. 108.  Paragraph S7.6.3 refers to Table I-a for the basic mounting location, which states that backup lamps must be placed on the rear.  Table V-a, referenced at S7.6.7, contains more specific visibility requirements that apply to backup lamps as installed on the rear of vehicles.  You state

that backup lamps located on the back of the cab or sleeper would meet those more specific visibility requirements; you have provided no documentation of this, but our answer to this letter assumes that you are correct.


Thus, assuming that backup lamps located on the back of the cab or sleeper meet the visibility requirements of Table V-a, the question is if placement on the back of the cab or sleeper would be on the rear of the vehicle for purposes of FMVSS No. 108.  A literal interpretation of the location requirement on the rear, would be on a vertical plane that is perpendicular to the longitudinal axis of the vehicle and tangent to the vehicles rearmost extremity.  However, the rearmost extremity of a vehicle is typically a bumper, trailer hitch, or other feature.  Mounting lamps at these locations is not generally practicable.  Considerations of practicability may also justify mounting the lamps even farther forward.  However, there are limits to this.


NHTSAs interpretations of on the rear have analyzed how far forward of the vehicles rear extremity lamps could be mounted and still be considered on the rear as required by FMVSS No. 108.  Backup lamps mounted on the rear are necessary to notify the viewer of the location of the rear extremity of the vehicle, and therefore cannot be too far from it.  For example, in response to an inquiry regarding placing rear lamps 27 inches from the rear edge of the vehicle, we stated that in that position, lamps are not mounted on the rear within the meaning of FMVSS No. 108. See our letters to Howard Kossover,[1] Jack Rademacher,[2] and George Manset.[3]


These interpretations regarding other lamps required to be on the rear are relevant to your question about backup lamps, because, like backup lamps, they indicate location of the rear of the vehicle and signal driver intent to other vehicles and pedestrians.  Accordingly, we do not agree that mounting backup lamps on the cab or sleeper, which can be many feet from the rearmost extremity of the vehicle, would meet the FMVSS No. 108 requirement for mounting the lamps on the rear. A lamp mounted on the cab would not necessarily be prohibited by FMVSS No. 108, however, provided that a backup lamp is mounted on the rear of the vehicle and provided that the additional lamp does not impair the effectiveness of required lamps.


If you have further questions, you may refer them to Analiese Marchesseault of my staff (202-366-1723).






                                                                                    O. Kevin Vincent

                                                                                    Chief Counsel


Dated: 9/9/13

Ref: Standard No. 108




[1]Letter to Howard Kossover,  Jan. 9, 1990, available at (last accessed August 8, 2013).

[2] Letter to Jack Rademacher, Aug. 22, 1990, available at (last accessed August 8, 2013).

[3] Letter to George Manset, Nov.16, 1999, available at (last accessed August 8, 2013).