Maryland Code, Transportation § 21-311

(1) A vehicle may be driven only on the right-hand roadway, unless directed or permitted to use another roadway by a traffic control device or a police officer;

(2) A vehicle may not be driven over, across, or within the dividing space, barrier, or section except, unless specifically prohibited by public authority, through an opening in the space, barrier, or section or at a crossover or intersection; and

(3) A vehicle may not be driven on the median strip, unless permitted to do so by public authority.