A road train, also known as a land train or long combination vehicle (LCV) is a semi-truck used to move road freight more efficiently than single-trailer semi-trucks. It consists of one semi-trailer or more connected together with or without a tractor. It typically has to be at least three trailers and one tractor.

A semi-trailer truck, is the combination of a tractor unit and one or more semi-trailers to carry freight. A semi-trailer attaches to the tractor with a type of hitch called a fifth wheel.