Did you know that at superspeedways like Daytona, two or more cars running nose-to-tail can run faster than one?
On the racetrack, both drag and downforce are affected by the air flow off nearby cars. In a common drafting situation, a lead car blocks much of the incoming wind, reducing the friction drag for a trailing car.
Junior Johnson, the winner of fifty NASCAR Races (1950 & 1960) discovered the phenomenon of drafting (sometimes called the slip stream), invented the tactic, and became the first driver to win with it, in the second Daytona 500, in 1960. Then, as an owner, he understood sooner than anyone else that cars could be designed to optimize drafting for his drivers, who included Bobby Allison, Cale Yarborough and Darrell Waltrip.