Licensing is an easy to way to require every adult cyclist to be trained in the rules of the road. I think many salmoners, ninjas, and sidewalk jumpers do so because they feel it's the best way to ride.

What about including cycling training in high school driver's education courses? Or guaranteeing cycling questions on the driver's test? You won't hit everyone, but I think it would do enough to make the erratic cyclist a tiny minority.