What is the risk, every time you get in your car and drive, of being
in an auto accident in the United states?

I'm not certain if the risk can be broken down that far, but across one's lifetime:

"the average American stands about a 1-in-100 or 1-in-200 chance of
dying in an automobile."

http://www.space.com/scienceastronomy/solarsystem/asteroid_fears_020326-1.html

Perhaps this will be of some help.

Have a good day.