Combination vehicles must display license plates _________.

All vehicles except motorcycles, motorized pedal cycles, trailers, semitrailers, truck tractors and vehicles registered under the International Registration Plan (IRP) must display two license plates (front and rear) on the vehicle.
Trailers must display one on the rear, and truck tractors must display one on the front. Buses registered under the IRP must display one apportioned plate on the rear of the bus