NASCAR racecars are very dependent on aerodynamics, especially on superspeedways. When two or more cars run one after the other at high speeds, they divide the amount of wind resistance (drag) between them -- and less resistance means more speed. That's why it's so common to see cars running bumper-to-bumper on superspeedways. This technique is called drafting, and it's a crucial art to master if a driver wants to win a superspeedway race
