TALLADEGA, Ala. -- The 3½ inch fin that NASCAR implemented for the left side of the rear deck lid and window for the Daytona 500 will be used at all tracks once the spoiler is introduced, expected to be at Martinsville on March 28, to help keep cars on the ground.
It was determined during wind tunnel tests after Brad Keselowski's car went airborne in the closing laps at Atlanta Motor Speedway two weeks ago that the fin would decrease the probability of liftoff.
They were introduced at the Daytona 500 with the intent of being used only at restrictor plate tracks.
"It is an asset we can use everywhere," series director John Darby said.
Kurt Romberg, the chief of aerodynamics at Hendrick Motorsports, said the fin helps break up the air and prevent a low pressure area from developing across the top of the car that creates liftoff.
David Newton covers NASCAR for ESPN.com. He can be reached at email@example.com.