Interesting racing safety aerodynamics
 

Racing aerodynamics are mostly refined going in...one direction.
https://www.youtube.com/watch?v=WzMY-fPLOiA

Besides the reverse alignment to airflow, they speculated that the center wicker bill may have contributed to some unstable lift that could have caused Castroneves' car to fly.
Chevrolet teams told to remove wicker after Castroneves crash | INDYCAR news | Motorsport.com

In 1994, NASCAR's crash lessons from spins and flips made it mandatory to include roof flaps. Jack Roush and Embry-Riddlle Aeronautical University helped design multiple flaps that keeps them from spinning and safely down on the ground.
https://www.youtube.com/watch?v=uwID6XZ9UY8

NASCAR Generation-6 cars have additional cowl flaps at another high lift section of the new car's profile.
http://i2.wp.com/www.buildingspeed.o...size=400%2C255