A trailer can only form a complete transportation tool when combined with a tractor or other automobiles

A trailer refers to a vehicle that is towed by a car but lacks its own power drive device. It consists of a combination of a car (truck, tractor, or forklift) and one or more trailers. The cargo vehicle and the towing vehicle are the driving sections of the car train, known as the main vehicle. The subordinate vehicle section towed by the main vehicle is called the trailer. It is an important type of vehicle in road transportation, and using car trains for transportation is the most effective and simple means to improve economic efficiency. It has the advantages of speed, maneuverability, flexibility, and safety; it can facilitate regional transportation.