In my limited experience, the worst users are the runners pushing double baby carriages. I've seen a couple of these and they were both running toward traffic in the bike lane with a 3 foot wide double baby carriage. A runner/walker is correct to go against traffic, but you add that baby carriage and you have a moving hazard that is difficult to avoid. They should move in the direction of traffic since they can't just step to the side to avoid a collision.