Knee room

Knee room is the clearance between the front of a car seat and whatever sits ahead of it, the dashboard for a driver or the seatback in front for a rear passenger. It is usually the very first limit a tall person hits in a vehicle, often before headroom becomes a problem at all.

Seat track length, meaning how far back the seat itself can slide, matters as much as the raw knee room figure, since a car with generous space but a short seat track can still leave a tall driver's knees pressed against the wheel or dashboard. Steering wheel tilt and telescoping range also affect how much usable room actually exists once the seat is set correctly.

A seat cushion designed for tall drivers can help by adjusting seat height and angle rather than adding legroom directly, which changes hip position enough to relieve some pressure on the knees and lower back during long drives. For a genuinely tight vehicle, no cushion fully replaces the need for adequate seat track length and knee clearance to begin with.