You will have a fresh wound on your spine that needs to heal. Just resting against your car seat will rub your incision with every bounce and turn the vehicle makes. I would try a soft pillow to reduce some of the friction on your wound and try to sit somewhat sideways. Don't travel for more than 30-45 minutes at a time if possible. Get out to walk and stretch your legs. Also try to change your position every 30 minutes while sitting or standing to reduce back pain. You could also lean forward on your car seat to try to avoid the friction. Riding in a vehicle could be uncomfortable for the first two to four weeks. You'll find sleeping on your side will be more comfortable. That helps relieve pain and pressure. In the hospital, they had pillows behind my back so I could sleep on my side. A body pillow would help with that. If you have a vehicle that would allow you to lie down on a soft pad on your side, with pillows supporting your back might be helpful. I had a 9 hour ride home and was constantly changing positions and leaning forward to try to avoid contact with my incision. I never did find a very comfortable position. That would be the one time I would suggest you use your pain medications as directed. Don't try to wean off until after you are home for a day or two. I also went to see a nurse in my family doctor's office to have a wound check a day or two after I got home. They changed the dressings for me at that time.