I probably would have guessed 1 in ~400.

It might drop to that once you turn like 26. A lot of these deaths are the result of deciding that it's a good year to give 17 year old boys a 2 ton death machine. They're generally needlessly dangerous and it's preferable we use trains and busses where the risk is reduced both generally and by stricter requirements for operators. But the lifetime risk is exaggerated because we've built society around requiring that people who don't have full appreciation of their own mortality have access to cars.