both my dad and uncle rode bikes for years, and between them they had a few serious stacks all caused by cars that 'didnt see them' or cut them off. my cousins ex husband is dead because of an impact with a truck. they were all good riders, attended track days, my uncle even competed in 250s for awhile.
the point is you can never predict what will happen/change in a street environment, no matter how good driver/rider u are.
even once when i was cruising out in the country at night, and my passenger spots a kangaroo sitting on the side of the road during a corner i just passed, if it had decided to cross (which most seem to do) there would have been no way i could have braked in time, also at the brisk pace we were going (not over the limit) it would have been quite a mess.