Md. Code, Public Utilities § 9–206

(a) The owner and operator of an intrastate motor bus carrier shall prohibit the smoking of tobacco products while the bus is in public service.

(b) A person may not smoke tobacco products on a bus of an intrastate motor bus carrier.

(c) The Commission may adopt regulations to carry out the provisions of this section.

(d) A person who violates a provision of this section is subject to a civil penalty not exceeding $25.