cars) uses the lead car's wake to pull up with maximum momentum at the end of a straightaway, enters a turn high, and turns down across the lead car's wake. The combination of running downhill and running across the zone of lowest aerodynamic drag allows the trailing car to carry extra speed and pass on the inside of the leader. Drafting was discovered by stock car racers in the 1960 Daytona 500, when Junior Johnson found that he could use drafting as a strategy that helped him overcome the fact that his Chevrolet could not keep up with other cars, allowing him to win the race. Like Johnson, other drivers found they picked up speed running closely behind other cars; and as they experimented they found that a line of cars could sustain higher speeds and/or use less gas (resulting in fewer pit-stops) than a single car running by itself. In recent years, as aerodynamics have become increasingly critical to the performance of stock cars on "intermediate" oval tracks (between 1.33 and 2 mi) and superspeedways not requiring restrictor plates (such as the Indianapolis Motor Speedway), the effect of turbulent, or "dirty" air when following closely behind another car has become much more akin to that described above in open-wheel racing (a situation described in NASCAR circles as aero push), and is often cited as a main reason for a decrease in the amount of overtakes. Bump drafting Drafting is most important at NASCAR's restrictor plate tracks, Talladega Superspeedway and Daytona International Speedway, where the plates mean that much less power is available to push the large bodies through the air. Race cars reach their highest speeds on these superspeedways, so the aerodynamic forces are highest, and the effects of drafting are strongest. Since restrictor plates were first used as a safety device, their effect has changed the nature of drafting. Vehicles no longer have sufficient horsepower or throttle response to maintain their drafting speeds upon exiting the draft; they can pull out and squeeze ahead but lack the response to clear the car being passed. This negates the slingshot maneuver. As a result, passing is often the result of cooperation between two or more drivers or is achieved by sucking air off the side of the car being passed, a technique called side-drafting. Bump drafting is a tactic used at Talladega and Daytona. The technique was initially popularized by