An aerodynamic automobile is designed to streamline the wind, it does not have piercing edges that cross the wind stream above the windshield and have a type of tail, which is called a liftback or Kammback or fastback. Different automotive companies like the Volkswagen, Loremo and Aptera, try to reduce the tail area of their small vehicles like the 1-liter models. They are designed to have a smooth and flat floor for the Venturi effect to be supported and generate the desired downwards-aerodynamic energy. The wind entering the engine cove is used for combustion, passengers and cooling, and then it is re-injected by an outlet under the floor. Air is slowed and pressurized in a diffuser for rear and mid engines, it loses a little pressure while it is passed through the engine cove and is filled in the slipstream. A seal between the high pressure around the gearbox and low pressure area around the wheels is required by these cars. The suspension in these cars is either retracted or streamlined and the engine cove floor is closed. Streamlined shape is given to the roof rails, antenna and door handle. A round fairing as a nose is given to side mirrors. Though racing cars need airflow through the wheel base for break cooling and a lot of air is emitted from the radiator into the wheel bay, it is said to cause increase in drag.
“Most aerodynamic design work is actually done initially on a computer, then the design is checked and modified by placing a vehicle with that design in a wind tunnel” (Erjavec 158). Wind tunnel and computer modeling are used to analyze and study automotive aerodynamics. The tunnel is sometimes furnished with a rolling road to achieve most accurate results from a wind tunnel test. The rolling road is a movable floor like the floor of at treadmill and moves at a particular speed as the air flows in. This affects the results by preventing the formation of a boundary