Automotive aerodynamics

For some classes of racing vehicles, it may also be important to produce downforce to improve traction and thus cornering abilities.

[1] As early as the 1920s engineers began to consider automobile shape in reducing aerodynamic drag at higher speeds.

[2] By the late 1960s scientists also became aware of the significant increase in sound levels emitted by automobiles at high speed.

These effects were understood to increase the intensity of sound levels for adjacent land uses at a non-linear rate.

The main purpose of a rear spoiler in a vehicle's design is to counteract lift, thereby increasing stability at higher speeds.

One of the first production passenger automobiles to swap out mirrors for cameras was the Honda e, and in this case the cameras are claimed by Honda to have decreased aerodynamic drag by "around 90% compared to conventional door mirrors" which contributed to an approximately 3.8% reduction in drag for the entire vehicle.

[9] It is estimated that two side mirrors are responsible for 2 to 7% of the total aerodynamic drag of a motor vehicle, and that removing them could improve fuel economy by 1.5–2 miles per US gallon.

The grille in most production vehicles is generally designed to maximize air flow through the radiator where it exits into the engine compartment.

[12] Fender skirts are often made as extensions of the body panels of the vehicles and cover the entire wheel wells.

Boattails create a teardrop shape that will give the vehicle a more streamlined profile, reducing the occurrence of drag inducing flow separation.

Nonetheless, for practical and style reasons, a kammback is more commonly seen in racing, high efficiency vehicles, and trucking.

It is very important to produce a good downward aerodynamic force because it affects the car's speed and traction.