I do this also - and it is usually helpful when a driver is turning across traffic into your path, exiting an adjacent drive, or turning from a side street. The problem in my earlier situation was that she never really looked behind before turning.

If a driver passes you, then wants to turn, they will sometimes remember (I've encountered many that didn't) passing a cyclist, and will look to see your progress before executing the turn. In my case, I was moving slightly faster than traffic due to congestion. They never passed me, I was overtaking them.

And that seems to pose the problem. I think most drivers view the bike lane as merely a widening device that serves no real purpose other than to provide more space for autos (SUVs ). If a driver wants to turn across the lane, they do so without regard. Especially if there is no prior indication of a bicycle. If they don't immediately see a cyclist, they don't give any thought to just turning across the lane because that extra road space is not registered with any meaning in their mind.

Anyway, I attribute my acrobats to the many action films I've watched (OK, it was really just weird luck) And I will add that I have had similar scares along this stretch of road because of the rush hour congestion and my ability to proceed at a faster pace. Much of it is downhill, so I usually have to ride the brakes. Although I could go much faster, I try to minimize the speed difference between myself and traffic. But, as I found, I am still going a bit too fast to completely avoid a sudden danger. I refuse to slow to a crawl though - I just keep my spider senses reeling and watch lots of Jackie Chan while waiting for the chance to spring into action!