Roof flap

In the first, Rusty Wallace barrel-rolled through the infield of Talladega Superspeedway in 1993 after being tagged by Dale Earnhardt exiting the tri-oval.

In August of that same year, Johnny Benson Jr. spun off turn two at Michigan International Speedway and flipped down the backstretch.

NASCAR tested a restrictor plate at Charlotte Motor Speedway that September but driver lobbying led to development of the roof flaps.

These flaps are designed to deploy as the truck goes around, venting the air through the bed cover, which often acted as a parachute before.

However, upon introduction at Talladega Superspeedway that fall, it was found that the center flap would often deploy on track as the trucks qualified or raced.