The taxable gross weight of a vehicle (other than a bus) is the total of:
The actual unloaded weight of the vehicle fully equipped for service,
The actual unloaded weight of any trailers or semi trailers fully equipped for service customarily used in combination with the vehicle
The weight of the maximum load customarily carried on the vehicle and on any trailers or semi trailers customarily used in combination with the vehicle.
Actual unloaded weight of a vehicle is the empty weight of the vehicle.
Fully equipped for service includes the body (whether or not designed for transporting cargo, such as a concrete mixer); all accessories; all equipment attached to or carried on the vehicle for use in its operation or maintenance; and a full supply of fuel, oil, and water. The term does not include the driver; any equipment (not including the body) mounted on, or attached to, the vehicle, for use in handling, protecting, or preserving cargo; or any special equipment (such as an air compressor, crane, or specialized oilfield equipment).