You don't seem to understand. Cars can not legally pass bicycles and stay in a single lane. The math does not work out when you take into consideration that bicycles need to keep a greater distance to the right to avoid morons who open doors into traffic and that, having only two wheels, they will naturally swerve left and right, and often do so on purpose to avoid the various pitfalls that are not maintained roads, where a light hit to the suspension on a normal car can dead stop your wheel and send you flying.