Check out this animation to see all the hazards a bicycle driver faces when trying to stay to the right.
Driving in the middle of the lane actually protects cyclists against the most common motorist-caused crashes: sideswipes, right hooks, left crosses, and drive-outs. A bicycle driver’s top safety priority is to ensure he or she can be seen by motorists with whom they might potentially be in conflict, and bicycling in the middle of a lane is one of the most effective ways to do that. Most overtaking crashes involve a motorist who attempts to squeeze past (illegally) in a lane that is too narrow to share. From CyclingSavvy.
Exclusion zone concept by Dan Gutierrez. Learn more.