Interpretation ID: nht71-4.31

DATE: 10/22/71

FROM: AUTHOR UNAVAILABLE; Lawrence R. Schneider; NHTSA

TO: National Association of Motor Bus Owners

TITLE: FMVSR INTERPRETATION

TEXT: This is in reply to your letter of August 2 to which you attached a letter from Mr. W. Dershko of Motor Coach Industries concerning the certification regulations that go into effect January 1, 1972. (Perhaps by error, you referred to a letter from Mr. Stieber of Greyhound Lines.) Rulemaking concerning gross axle weight rating and gross vehicle weight rating was in process at the time, hence the reason for our delay.

Mr. Dershko asked whether the gross vehicle weight rating must equal the sum of the gross axle weight ratings. The answer is no. The practice described, of stating a GVWR less than the sum of the GAWR's, will be quite proper under the new regulations.

Mr. Dershko also said that he was concerned as to how to interpret the definition of gross axle weight rating, and that "several factors to consider are the tire capacities, axle assembly capacity, and the coach frame structure capacity." We agree that all those factors must be considered. The manufacturer must set his gross axle weight ratings in view of the weakest elements in the load-bearing systems of the vehicle.

Let us know if we can be of further assistance.