If you expect drivers to yield to you, give you your lane, and (most importantly) not actively work to bring about your death, you can't be weaving in and out of traffic, running red lights, or not letting cars through to turn at intersections. Even if you don't give half a damn about your own life, it's just simple courtesy.
In general, people on bicycles in DC combine the worst parts of the "urban road warrior" cyclist stereotype with the intense sense of entitlement and privilege shared by most in the DC area: "why the fuck should I stop at a red light? I have places to be. I saw David Axelrod at Ruth's Chris yesterday. Do you know who the fuck I am?"
The drivers are insane as well, but I want to grab most of the cyclists I see around here by the shoulders and shake them hard: "Do you want to die??!? DO YOU??!!!?" They are just the worst and sicken me deeply every day.
Disclaimer: I am a frequent cyclist in DC.
I wouldn't say it's all that safe on the street in DC. I've very nearly been run over by cars (especially cabs) that want to turn right out of a circle (which even has a bike lane).