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Interpretation ID: 002101GF

    Mr. Charles W. Lawhon
    C & S Trailer World
    4111 E. Loop 820 S.
    Fort Worth, TX 76119

    Dear Mr. Lawhon:

    This letter is in response to your phone call and a subsequent letter asking about the Federal motor vehicle safety standards that apply to a trailer with a gross vehicle weight rating (GVWR) at or above 10,000 pounds that was manufactured in 1987. Specifically, you asked about any regulations applicable to such a trailer equipped with an "electrical braking system." It is our understanding that this electrical system actuates brakes via an electro magnet and does not utilize air or hydraulics. You also asked us to elaborate on any other safety requirements for "manufactured utility or gooseneck trailers."

    I am pleased to have this opportunity to explain our regulations to you. As a preliminary matter, we note that the National Highway Traffic Safety Administration (NHTSA) does not provide approvals of motor vehicles or motor vehicle equipment. Under the National Traffic and Motor Vehicle Safety Act ("Safety Act"), it is the responsibility of the manufacturer to ensure that its vehicles or equipment comply with all applicable Federal motor vehicle safety standards (FMVSS) issued by this agency. A manufacturer then certifies that its vehicles or equipment comply with those standards.

    There is only one Federal motor vehicle safety standard that regulates the braking performance of trailers.[1] That standard, FMVSS No. 121 (49 CFR 571.121) establishes performance requirements for braking systems on vehicles equipped with air brakes. The standard applies to new trucks, buses, and trailers. A trailer manufactured in 1987 would have been subject to the standard as it existed at that time. An air brake system is defined in paragraph S4 of the Standard as follows:

    Air brake system means a system that uses air as a medium for transmitting pressure or force from the driver control to the service brake, but does not include a system that uses compressed air or vacuum only to assist the driver in applying muscular force to hydraulic or mechanical components.

    Based on your correspondence, it is our understanding that the trailer in question uses electricity to actuate or control its brakes. Accordingly, the trailer you described is not subject to the requirements of Standard No. 121.

    In addition to Standard No. 121, Standard Nos. 106 and 116 are also applicable to trailers manufactured in 1987 and today. Standard No. 106 regulates brake hoses and Standard No. 116 regulates brake fluids. Again, it is our understanding that the trailer in question was equipped with an electrical braking system. Therefore, Standard No. 106 and Standard No. 116 do not apply to that vehicle, because the system does not contain brake fluid or brake hoses.

    In you letter you state: "there were no safety regulations in regards to trailers with straight electrical brakes or any other safety devices in 1987." This statement is not correct. There are several safety standards that applied to all trailers manufactured in 1987. Specifically, Standard No. 108 regulates certain lamps, reflective devices and associated equipment installed on trailers. The specific requirements under this standard depend on the size of the trailer, which you have not provided. Standard No. 119 applies to new pneumatic tires installed on trailers manufactured after 1948. Standard No. 120 applies to tire selection and rims for motor vehicles other than passenger cars, including trailers.

    In sum, there was no Federal motor vehicle safety standard applicable to electrical braking systems installed on trailers manufactured in 1987. However, several other safety standards were applicable to trailers manufactured in 1987. For your convenience, I have enclosed a package of information for trailer manufacturers, published by our Office of Vehicle Safety Compliance. This information is also available on the web at:

    I hope this information is helpful. If you have any further questions about NHTSA's safety standards, please feel free to contact George Feygin of my staff at this address or by telephone at (202) 366-2992.


    Jacqueline Glassman
    Chief Counsel


    [1] In 1987, FMVSS Standard No. 105 Hydraulic brake systems, applied only to passenger cars, MPVs, trucks, and buses. We note that the application section of the current version of Standard No. 105 states that it applies to "hydraulically-braked vehicles with a GVWR greater then 3,500 kilograms." The application section does not exclude trailers. However, this is an error, and we intend to issue a correcting amendment to exclude trailers, as was the case in 1987.