Cars can be generally divided into six categories according to their uses: ① Cars, also known as passenger cars, generally have no more than 9 seats (including the driver's seat). (2) Passenger cars with more than 9 seats (including driver's seat), including city buses, road buses and tourist buses. (3) Trucks, commonly known as trucks, are mainly used to transport goods. (4) Tractor, specially used for towing trailer or semi-trailer. ⑤ Special transport vehicles, designed according to the special requirements of transporting goods, have special carriages and are equipped with corresponding auxiliary equipment, such as dump trucks, liquid tankers, refrigerated trucks, bulk cement trucks and container trucks. ⑥ Special vehicles are mainly used to complete other tasks, such as ambulances, fire engines, garbage trucks, sprinklers and various engineering vehicles.