[§291C-51]  Driving on divided highways. Whenever any highway has been divided into two or more roadways by leaving anintervening space or by a physical barrier or clearly indicated dividingsection so constructed as to impede vehicular traffic, every vehicle shall bedriven only upon the right-hand roadway unless directed or permitted to useanother roadway by official traffic-control devices or police officers.  Novehicle shall be driven over, across, or within any such dividing space,barrier, or section, except through an opening in such physical barrier ordividing section or space or at a cross-over or intersection as established,unless specifically prohibited by public authority. [L 1971, c 150, pt of §1]