What is the Air current made by race cars?

Answer 1

It's called "Turbulence".

The air currents made by all cars is the same (and all moving objects for that matter). However, race car drivers use a technique called "Drafting" to gain speed by hiding in the low-density air behind another car, decreasing air-resistance and allowing the car to accelerate faster. Some people use it to save gass by following in the low-density air current behind semi-trucks. Making it so that their engines don't need to work as hard to maintain speed.