Interpretation ID: nht75-3.45

DATE: 06/06/75

FROM: AUTHOR UNAVAILABLE; J. C. Schultz; NHTSA

TO: TTMA

TITLE: FMVSS INTERPRETATION

TEXT: This responds to the Truck Trailer Manufacturers Association's May 1, 1975, request for a determination of what speed the National Highway Traffic Safety Administration (NHTSA) considers as "highway speeds" in establishing gross vehicle weight ratings (GVWR) and gross axle weight ratings (GAWR) under the requirements of 49 CFR @ 567.4 (g)(3) and (4).

For purposes of GVWR-GAWR calculations, NHTSA will consider "highway speeds" to be the 60 mph value used by the United States Tire and Rim Association in assigning unqualified ratings to their tires. Therefore, trailers which are capable of speeds of 60 mph or more should be assigned ratings which reflect vehicle capabilities at 60 mph.

SINCERELY,

May 1, 1975

James C. Schultz Chief Counsel National Highway Traffic Safety Administration

In regard to your letter of March 5, 1975, you state that "A vehicle capable of highway speeds and reasonably expected to be operated at such speeds is subject to Standard No. 121 - Air Brake Systems at weight ratings specified for highway speeds".

Advice would be greatly appreciated as to the numerical value NHTSA has assigned to the term "highway speeds".

Don W. Wieriman Staff Engineer-Tank Vehicles