“Sharrow” striping is one of the stupidest ideas ever devised by road planners. Designed to avoid political conflicts on removing parking or auto lanes — they are quite useless for cyclists. Indeed, sharrows may increase the risk to cyclists according to a recent UBC study. Lots of good data in the study, but here is the main result:
The study also found traffic circles to be extremely dangerous. That is a surprising and controversial result.
Update: Here is the main link to the study group, with some additional info.