sentence: Truck drivers are called 'truckers'.
sentences_before: In the U.K. they are known as 'lorries'. Often heavy trucks pull trailers. A semi-trailer is a kind of trailer which has wheels only in the back and the front rides on the back of the tractor unit. The tractor unit has an engine and the semi-trailer does not. Driving a heavy truck requires a professional driver's license.
concept_name: truck driver
headings: Truck Types of trucks by size Heavy trucks
categories: Car body styles