What is the terminal velocity of a car?

Assuming atmospheric conditions density of air being 0.0765 pounds/cu. ft. and assuming the car weighs 4000 lbs with dimensions of 6'x15'x5', with a drag coefficient of approximately 0.2...

The terminal velocity of a car under these conditions would be about 52 mph. This is assuming it's falling flat. If the car was falling pointing down, the terminal velocity would be something more like 90mph. Obviously this answer will vary by changing the assumptions.