A tractor trailer is made up of a tractor unit (the vehicle's power unit) and a semitrailer (connected to the tractor unit). The tractor unit is usually a large truck that pulls the trailer. A tractor trailer is a huge trailer, usually a flatbed, that transports cargo. Tractor trailers haul huge and heavy cargo including building materials, agricultural supplies, and manufactured goods. Contact our Fieldking team to learn more about tractor trailer prices and types.