W. Va. Code § 17A-10-2
The declared gross weight as stated in the application for registration shall be the basis for determination of fees to be paid for operation of trucks used separately and not in combination with other vehicles in transportation of property.
The basis for determination of fees to be paid for operation of trucks, truck tractors, and road tractors used in combination with other vehicles for the transportation of property shall be the combined declared gross weight of the truck, truck tractor, or road tractor and the vehicle to be drawn by such truck, truck tractor or road tractor; the declared gross weight of the entire combination of truck, truck tractor, or road tractor and the trailer or semitrailer to be drawn by such motive vehicle to be considered as one unit for purpose of determining the fees to be paid for such truck, truck tractor, or road tractor.
The basis for determination of fees to be paid for operation of Class H vehicles shall be the manufacturer's declared weight plus one hundred and fifty pounds for each seat.
W. Va. Code § 17A-10-2