<Li> Box or van trailers are the most common type . Standard lengths in North America are 28 ft 0 in (8.53 m), 32 ft 0 in (9.75 m), 34 ft 0 in (10.36 m), 36 ft 0 in (10.97 m), 40 ft 0 in (12.19 m), 45 ft 0 in (13.72 m), 48 ft (15 m), 53 ft 0 in (16.15 m) and 57 ft 0 in (17.37 m). </Li> <Li> Bus - bodied trailers are hitched to a tractor unit to form a trailer bus, a simple alternative to building a rigid bus . </Li> <Li> Car carrier trailers carry multiple cars, usually new cars from the manufacturer . In the US and elsewhere, car carriers often carry used vehicles as well . Similar variants can carry fork lift trucks, light commercial vehicles and agricultural tractors . </Li> <Li> Conestoga trailers are a special form of flatbed trailer with a flexible retractable roof and siding used to carry large pieces of equipment that can only be lifted by an overhead crane, but which also need protection from the weather during transit . </Li>

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