In my Jeep I have a strap I tie my chair down with when I off road. I my car I put the chair in the back seat and lean the passenger seat back against it.
I've had the chair come slamming into the back of the front seat a couple times from making quick stops.
I have seen safety movies of what happens to a person not held in by a seat belt in an accident. They fly around in the car like a ping pong ball.
In an accident I figure the one in the car is going to come up and beat me to death.
So what are people doing to keep their chair from beating on them?