headroom

noun
1
the amount of space between the top of a vehicle and an object it drives under
ارتفاع سقف, فاصله سقف تا شیء
2
the amount of space between the top of your head and the roof of a vehicle
فضای سر, ارتفاع سقف برای سر
There's a lot of headroom for such a small car.
The new model gives generous headroom for front and rear passengers.