Are 2-way bike lanes safe? For this question, I'm referring to bike lanes of the type shown here: 



To me they seem like a really bad idea.  Firstly, one of the lanes is going against traffic.  In this instance, the cars turning left at the intersection have to look behind them to see if bikes are coming from behind. Also, it seems that it would be really difficult to pass another cyclist if the path was busy, since the only way to move around another cyclist is to go into the opposite lane, against the traffic of the other bikes.  The only advantage I can see over regular bike paths is that for the most part you are cut off from the cars.  However, I've never had a problem with cars using "regular" bike lanes. Are there any studies as to how well these lanes work?  Does anybody have any experience with these kids of bike lanes?  How do you like them compared to other types of bike lanes?

Part of my concern is shown in this video (skip to 2:50).  The lanes seem to move really slowly, and there seems to be a lot of people in the wrong lane completely.  It seems like it would be nice for people taking a leisurely Sunday ride with the kids, but if your actually trying to commute and get somewhere in at a reasonable speed, it seems like it would be impossible.
Studies done by the school of Health at Harvard, and published in Injury Prevention, are showing these to be safer. 

http://www.hsph.harvard.edu/news/features/coverage-in-the-media/bicycling-safety-cycle-tracks-lusk/index.html