Interpretation ID: nht72-5.34

DATE: 03/21/72

FROM: AUTHOR UNAVAILABLE; Richard B. Dyson; NHTSA

TO: Truck Equipment & Body Distributors Association

TITLE: FMVSR INTERPRETATION

TEXT: This is in reply to your letter of February 23, 1972, concerning the application of the Certification regulations (49 CFR Part 567) to certain vehicles and components.

You describe a device, called a "converter gear", which is used to convert a semi-trailer into a trailer, and ask whether this unit is considered to be a trailer which must be certified. You also ask whether all lamps and reflectors specified for trailers are required. We believe this device to be a trailer, as it appears from your description that it is a "trailer converter dolly" under the Motor Vehicle Safety Standards (49 CFR @ 571.3). Trailer converter dollies are specifically exempt from the requirements of Motor Vehicle Safety Standard No. 108, "Lamps, Reflective Devices, and Associated Equipment," and are consequently not required to meet the lighting requirements applicable to other trailers. In addition, there are presently no other motor vehicle safety standards applicable to trailers and consequently, trailer converter dollies need not be certified. This will no longer be the case, however, after the effective date of Standard No. 121, "Air Brake Systems." Trailer converter dollies manufactured on or after that standard's effective date will be required to comply with its requirements, and to be certified in accordance with Part 567.

You also ask how manufacturers are to determine the GVWR for semi-trailers, and whether such a figure can be based solely on the semi-trailer's axle or axles. The GVWR of a semi-trailer should not be based on the vehicle's axles. The definition of GVWR calls for the weight of a fully loaded vehicle, and normally the capacity of a semi-trailer is greater than that of its rear axles.

You describe another device, a "Jo-Dog" or detachable tag axle to be attached to a truck tractor, asking whether this unit is a "trailer" which must be certified and whether the use of such a device would alter the truck tractor to the extent that an altered certification label is required. It appears from your description of this device that it is also a "trailer converter dolly." As in the case of the "converter gear" described above, certification by the manufacturer (at the present time) is not required. Moreover, we would not consider the use of such a device to be "manufacturing" within the National Traffic and Motor Vehicle Safety Act, and no certification of any kind by a user (as distinguished from a manufacturer) would be required.

Finally you describe additional devices, a "drom," and an auxiliary cargo-carrying platform, both of which can be added to truck tractors between the cab and the fifth wheel. You ask whether the installation of such devices would constitute re-manufacturing of the vehicle and if additional certification is required when compliance to a standard is not altered.

We would consider the addition of such components to a new vehicle to be manufacturing under the National Traffic and Motor Vehicle Safety Act, and certification by the vehicle manufacturer would be required regardless of whether compliance of the vehicle to any standard is affected.

We are pleased to be of assistance.