Motor vehicle. Any vehicle, machine, tractor, trailer, or any combination of these that is driven by mechanical power and used on the roadways in the transportation of people and materials.
Semitruck. A truck and trailer combination designed and used primarily for carrying material and property.
Trailer. A nonmotorized vehicle designed to be towed by a motor vehicle.
Truck. Any motor vehicle designed, used, or maintained primarily for the transportation of property.
Wash. Admin. Code § 296-865-099