Fuggedaboudit on small cars, much less even large pickups unless they have strong suspension. The easy solution is to strap a stepladder on top of your car and be done with it. They're much more portable, and taller too if you choose. If I need camera support while on a ladder, I just clamp on a Bogen Super Clamp with a ballhead mounted. Best news, ladders are also cheaper than roof racks.