The development of mechanical structures for wheeled vehicles has a very long history. The forms of vehicles can be classified according to the steering and powering of the vehicle as follows: 1) ordinary car-like robots (including passenger cars, single unit trucks, single unit buses and articulated trucks); 2) dual drive robots (dual drive motors with various casters); 3) synchronous drive and steering robots; and 4) omnidirectional robots. Kinematics forms the basis for feasibility analysis of the mechanism, motion feasibility, dynamics and control, trajectory planning and more complicated problem for an autonomous intelligent robot, such as path planning. This paper develops the unified kinematics, both the inverse and the direct types, for the four kinds of wheeled vehicles. The application of the kinematics in path planning problem is also presented.