A hatchback is a vehicle in which the cab and the trunk are combined into one and the engine is placed separately. From the exterior is a two-part vehicle (engine compartment and seat box). In terms of appearance, the sedan is composed of three parts—the engine compartment, the seat compartment, and the trunk. Compared with the sedan, the advantage of the hatchback is that the interior space is relatively large, but the trunk is quite small. Hatchbacks on the market today are more common in small and compact cars. Sedans are more common in Santana, Audi and Jetta. The sedan is a symmetrical shape from the side, with the sides low and the center high. The engine compartment and trunk are relatively low, and the middle high part is the seat box part. The advantage is that the overall shape is more beautiful. If the car is in an accident, the trunk can reduce the injury of the owner to a certain extent. The disadvantage is that parking is not convenient in congested cities.