(a) General rule.--Except as otherwise provided in this section, vehicles shall be registered for a flat fee.

(b) Classification of vehicles.--The department may identify vehicles by type as to weight, design, loading, use, ownership or other significant characteristics for purposes of registration.

(c) Trucks, truck tractors and trailers.--The department shall register trucks, truck tractors and trailers at the gross weight requested by the applicant, provided that the weight is not greater than allowed in subsection (d) or less than allowed in subsection (e).

(d) Maximum registered gross weight.--No truck, truck tractor or trailer shall be registered at a gross weight in excess of the lowest of:

(1) the limiting weights established on the basis of axle load, tire load, horsepower or gross weight by type of vehicles;

(2) the gross vehicle weight rating assigned by the manufacturer; or

(3) a combination weight greater than the gross combination weight rating.

In the case of a vehicle in which no gross vehicle weight rating or gross combination weight rating is assigned by the manufacturer or where the vehicle has been altered subsequent to manufacture to change its weight bearing capacity, an equivalent rating shall be determined by the department on the basis of the vehicle's horsepower, braking ability, axle limitations and such other factors related to safe operation as may be established by regulations of the department.

(e) Minimum registered gross weight.--No truck, truck tractor or trailer shall be registered at less than the total of the weight of the unladen vehicle, the maximum weight of the proposed load, the equivalent weight of the fuel capacity, 150 pounds times the seating capacity, and the weight of any permanently or temporarily attached appurtenances.

(f) Registered gross weight of trucks and truck tractors.--Every truck shall have its own registered gross weight and may also be registered at a registered gross weight for a combination. Every truck tractor shall be registered at a registered gross weight for a combination.

(g) Buses other than school buses.--The department shall register buses, other than school buses, on the basis of passenger seating capacity.