大多数专用汽车,尤其是运输类专用汽车一般采用普通载货汽车二类底盘进行改装,改装生产时一般不用(或很少)对底盘进行改动加工,只是在原底盘基础上,加装副车架、专用载货装置、取力装置和控制系统等,使之成为具备专业运输或某一专用功能的专用汽车。同一底盘可以用来改装不同类别的专用汽车,如自卸车、厢式车、罐式车、仓栅式车等,一般把该类底盘称为通用底盘。部分专用作业汽车,由于其专用作业功能或专用装置特殊结构特点,必须对二类底盘进行较大的改进后才能适应整车改装的要求,如 Most special purpose vehicles, especially transportation vehicles, are normally modified with ordinary second-class chassis trucks. In general, there is no need (or rarely) to modify and modify the chassis, except that the auxiliary chassis is added on the basis of the original chassis , Special cargo equipment, power take-offs and control systems, making it a specialized vehicle with a dedicated transport or a dedicated function. The same chassis can be used to modify different types of special purpose vehicles, such as dump trucks, vans, tank cars, warehouse trucks and so on, the general type of chassis called the common chassis. Part of the special operations vehicles, due to its special operating functions or special structure of the special device features, the second category must be greatly improved chassis to adapt to vehicle modification requirements, such as