In New Zealand, vehicle registration plates (usually called number plates) contain up to six alphanumeric characters, depending on the type of vehicle and the date of registration. To be operated on (or parked on) any public road, most types of motor vehicles and trailers must be registered and display the corresponding registration plate(s). One plate must be affixed to the rear of the vehicle, and except in the case of a motorcycle, moped, tractor, or trailer, a second plate must be affixed to the front of the vehicle.