Robotic vehicles on wheels represent the most effective robotic solution, in terms of cost and realization complexity, to achieve motion on flat terrain. The local mobility of wheeled robots, however, varies in accordance to the mechanical design of wheels, their type and their arrangement. This chapter aims at analysing how the design of wheels and their arrangement affects the mobility of vehicles and the associated modeling, planning and control problems. First, we review the main wheel types and a classification of vehicles based on their mobility, as determined by the arrangement of wheels and the associated kinematic constraints. Then, kinematic models of wheeled vehicles, having a single chassis or articulated bodies, are presented and analyzed. Particular attention is given to those aspects that determine the challenges of motion planning and control problems for wheeled robots and that have led to the development of new, specific planning and control methodologies with respect to fixed base manipulators.