Creating an exception to the prohibition against a person operating a bicycle or a motor scooter on a roadway where the posted maximum speed limit exceeds 50 miles an hour; and authorizing a person who is lawfully operating a bicycle or a motor scooter on a shoulder adjacent to a roadway for which the posted maximum speed limit exceeds 50 miles an hour to enter the roadway only if making or attempting to make a left turn, crossing through an intersection, or the shoulder is overlaid with specified directional markings.