Whenever any highway has been divided into two roadways by an intervening space, or by a physical barrier, or a clearly indicated dividing section so constructed as to impede vehicular traffic, every vehicle shall be driven only upon the right-hand roadway, and no vehicle shall be driven over, across, or within any dividing space, barrier, or section, except through an opening, crossover, or intersection established by public authority.  This section does not prohibit the occupancy of the dividing space, barrier, or section for the purpose of an emergency stop, or in compliance with an order of a police officer.
(ORC 4511.35)
Penalty - see Sections 307.01 and 307.02