When people see a loaded truck on the highway, most of them don’t realize the two halves of the truck—the load-carrying trailer and the tractor pulling it—could be owned by different companies. This is a type of transportation service called “power only trucking,” in which the company that owns the trailer hires the tractor and its driver from another company.
When power only trucking is an option, companies don’t have to buy and maintain their own truck fleets. They may choose to buy trailers, but those require far less maintenance than tractors do, and they don’t have to hire drivers full-time.