When a racecar is spinning, pressure increases inside a racecar that could cause the racecar to flip. Roof flaps open then this air pressure increases inside the racecar to relieve this pressure and keep the racecar from flipping.
The two flaps that rise when a car begins spinning out of control in order to catch the wind and limit a car's ability to become airborne.
These flaps are sections at the rear of a race vehicle's roof that are designed to activate, or flip up, if the air pressure flowing across them decreases. In the case of a vehicle turning backwards, the tendency for an uninterrupted flow of air is to create lift. The roof flaps are designed to disrupt that airflow in attempt to keep the vehicle on the ground.