Seeing how the teams build 60% scale models for the wind tunnel, what is stopping them from making remote controlled cars modeling their real cars and testing those on real tracks?
They could link up the remote controlling with a mobile version of their simulators, and even let the real drivers, test drivers or even computer controlled "driver" for maximum consistency.
They could use electric drivetrain for simplicity, but modeling the tires would be a problem... but it would still help in the aero department.
Have there been early attempts at this that I am not aware of? Or any major drawbacks that I have not yet considered?