I never thought I'd admit this but one of the safety rules made for disabled drivers is adequate. My usual wheelchair is broken so I have anotyher one which doesn't have a bolt to lock me in my van while I drive. I drove yesterday and all was fine but I drove today and it was scary. I started to make a left turn and I slid a little bit. Thank goodness I was going slowly and thank goodness there were very few cars on the road. Nonetheless, I was pushed into my steering column very close. I also had to make a sudden stop and I slid a bit too. So I guess I'll be spending the $800 for a bolt to go under this chair.