The wind tunnels used for full size cars are explained. The main specifications, maximum air speed, test section dimension, test section types, and wall interference are discussed first. Especially, the effect of adaptive wall test section is introduced. Five-belt moving belt system is shown with some examples next, which is the best ground simulation and most suitable for the cars. Finally, low noise wind tunnels and the improvement of conventional wind tunnels to the low noise type are written. Low noise wind tunnels are very popular today, because they are useful to decrease the wind noise of the cars.