RSA 266:18 Weight on Interstate and Defense Highway System.

The driving on the interstate and defense highway system of this state of any vehicle or combination of vehicles exceeding the limitations of this section is hereby prohibited.
I. Maximum tire and axle gross weights allowable:
(a) The manufacturer's load rating for the tires.
(b) When being driven with a gross weight in excess of 73,280 pounds:
(1) 20,000 pounds per axle on axles more than 8 feet apart;
(2) 17,000 pounds per axle on axles not more than 8 feet apart;
(c) When being driven with a gross weight not in excess of 73,280 pounds:
(1) 22,400 pounds per axle on 3-axle single unit vehicles and on all other vehicles with axles 10 feet or more apart, including combination vehicles;
(2) 18,000 pounds per axle on axles of vehicles le