do you know what also causes accidents?
cars
there is no regulations on cars (except age of course)
accidents happen in any way you can think of
You have to apply for a permit, take lessons and pass a test to get a photographic license with your details which is registered on the DVLA (or American equivalent) in order to drive a car. And if you don't drive responsibly, your license is taken away.
It would be a great start if the US introduced regulations like that on guns.