The bike lane along Second Avenue in downtown Seattle—shown above, with a truck blocking the entire lane just feet from a newly installed "yield to bicyclists" sign—is on the left side of a downhill road, sandwiched between fast-moving one-way traffic and a row of parked cars. Here are some of the many things that could happen to you as a cyclist on Second:
A passenger in a parked car could open his or her door into your path, knocking you down;
A driver could decide to turn in to a parking space, hitting you from the left;
A driver could turn out of a parking space, hitting you from the right;
A driver could decide the bike lane is their own personal driving lane;
A driver could decide to turn left and fail to yield to you, forcing you to stop abruptly or slamming in to you from the right.
The fear of all those outcomes is one reason I never, ever use the Second Ave. bike lane—unless I'm turning left, in which case I ride very slowly and take care to look behind me, because there's almost always a driver there who thinks he or she has the right-of-way over me.
Surprisingly, the Bikewise accident map shows only one recent accident on Second—a crash in which a driver turned in to a cyclist's path and the cyclist "got cut off and crashed into the rear of the car.
Anecdotally, I know crashes and near-crashes happen far more often than that. And, speaking of, here's an anecdote: A friend of mine was once hit by a cop in the Second Ave. bike lane. After he got up and dusted himself and his bike off, the cop called him over and gave him a ticket—for damaging his car.
This city has a long way to go.