• Can you adjust the seat to accommodate different leg lengths? To judge leg room, with your hands evenly placed on the steering wheel, you should be able to see equal amounts of both legs between the arms. If you can see the left leg, but not the right, this can result in rotating the pelvis when driving, which can cause more pain.
• Does the seat height adjust? There should be room for your fist between the crown of your head and the top of the car. If there is only room to put your flat hand between the top of your head and the roof, the car is definitely not offering enough head room for you and you will slouch in the seat, straining the back and thighs. Is the back rest angle made to be in either an upright or reclined position?
• Is it easy to adjust the headrest so the top is even with your eyes? This is the optimal position for support and helps prevent neck injuries in an accident.
• Can the front of the seat be adjusted in height so that it doesn't press against the back of your knees?
• Are the arm rests comfortable? Height adjustment for them is ideal, but often hard to find.
• Does the car have lumbar support? A seat with an inflatable lumbar support is ideal. You can adjust it to the perfect position for your comfort.
• What you can do to avoid back strain?
• Change your posture from time to time.
• Take breaks. Success does not depend on beating the land speed record your brother currently holds for the same trip.

There's a right way to get in and out of the car - have the seat back because you exited it correctly the last time. Sit first and then swing your legs in. Now adjust the seat, mirrors, etc. When getting out, put the seat back and swing your legs out before getting up.

If there's something in the back seat you need --CD's, Kleenex, map -- stop the car, get out and get the item. Reaching around from the front seat can wreck a healthy back.