When I posted earlier, I really mis-stated the width of the bike lanes. I guess I never really considered how wide they were before, and the above number seemed to fit about right in my head. I took a ride earlier with this topic in my mind, and realized that there's a lot more space in the bike lanes than I said there was.

Here's a picture showing cars parked in the bike lane.


Even with the cars there, there's still a lot of space available. you could probably park two cars next to each other in the bike lane. And there's plenty of space to go around an open door. Maybe this is why I don't see such a prblem with car doors - I'm used to riding with plenty of space and not even realizing it.