Two principles to be aware of when you are on a bike in auto traffic:
1. You are in the most danger when auto traffic crosses your path. Intersections are the most obvious example. Especially dangerous are turning lanes and off-ramps when you are going straight - cars that are changing lanes or preparing to turn are looking for other cars, not bicycles.
2. If you hear a siren, get off the road NOW. Cars will be trying to get out of the way of emergency vehicles, and looking to avoid other cars, not bicycles.
I've been a short-distance commuting cyclist since 1994. I've been hit once in traffic - at an off-ramp, by a car that was getting out of the way of a fire truck.