One of the most adaptable inventions is motor-powered vehicles, especially cars. The majority of the time, safety, SFC, and operating area were considered. Vehicle makers are examining the characteristics of drag or air resistance for different body forms at various operational situations in order to increase fuel efficiency, vehicle speed, reduce wind noise, and improvise road control and vehicle steadiness when moving. The study of the rigid body traveling across the atmosphere and the interactions among its surface and the atmospheric air with varying linear acceleration and air direction is called aerodynamics. Aerodynamic drag is generally insignificant at lower vehicle speeds, but as speed increases, the air resistance magnitude also increases. This chapter deals with the external properties design considerations and testing methods of road vehicle aerodynamics like drag force. Identifying the drag force by various methods like wind tunnel tests, coast down test, and computer fluid dynamics are explained to forecast the drag coefficient.