shorter tracks with steeper banking = more crashes.
as the other poster said, you race, and there will ultimately be crashes. how many, how often? it's like getting flats, you might not have any for 5 years, then get 5 in a week.
just accept it's probably going to happen, and that 99% of them don't result in anything too serious and then forget about the prospect of crashing, just go out and ride and enjoy.