In much of Boston, however, the streets were laid out when cars were just a figment of our imaginations. The speed limits are rarely more than 25mph, and even if they were higher, the road layout doesn't let cars get much faster even if they want to. If you're on a moderately efficient bike, you can take the lane with only a 5mph difference to traffic speed, which really isn't much of an inconvenience to anyone, and not all that frightening for the rider. Also, just about every block is lined curb-curb with parked cars (main streets and side streets), so while the odds of any one car opening a door may be exceedingly low, if I pass 150 parked cars each way to/from work every day, that's 78,000 parked cars each year. Assuming the odds of any particular car opening a door as I pass in 1 in a million, then on average, one of the 13ish people that I work with who commute by bike should get doored every year. If I pass only 15 parked cars each way, one of us gets doored every 10 years, and most never do in our working lifetimes.
In the years I have been in Boston, there are only 3 traffic situations that made me fearful. One is doorings (the only time they got me was when a taxi passenger opened the passenger door while the taxi was in the left hand lane, freak situation, I just chalk this one up to Harvard Sq.). Two is cars creeping out from driveways or side streets trying to see around parked cars (never got hit this way, but had some close calls). Three is a roundabout that leads onto a bridge with a bike lane (BU Bridge from the Cambridge side)... exiting the roundabout can be cars and bikes riding parallel (normal lane + bike lane), but as the exit veers right, without fail drivers regularly cut the corner and put their wheels in the bike lane (I have been side-swiped multiple time here, never seriously hurt thankfully). In all of these cases, the times I got into trouble were times I was lazy with my lane positioning and wandered too close to the curb and out of drivers line of sight. The remedy that soothed these situations was to ride further into the lane... no doors there, cars peeking out to turn can see you (and you are clear of their bumper), and drivers approaching from behind can see you easier (and have time to, due to speed differentials being minimal).