Trucker's vehicles are typically large semi-trailer trucks, also known as SEMIS. SEMIS are long-haul trucks that are used to transport goods over long distances. They are usually equipped with a tractor unit and one or more trailers, which are connected by a fifth wheel coupling. The tractor unit is the cab of the truck, while the trailer is the cargo area. SEMIS are an important part of the trucking industry, as they are used to move goods from one place to another.