Maryland Code, Public Utilities § 9-201

(1) a motor vehicle used exclusively for the transportation of pupils to and from public or private schools;

(2) a motor vehicle operated for a period of not more than 3 months in any registration year in the transportation of persons employed at a cannery located in a county;

(3) taxicabs;

(4) public transportation for hire authorized to operate on the boardwalk in Ocean City;

(5) a vanpool operation as defined in § 11-175.1 of the Transportation Article;

(6) a local public transportation system established under a law enacted by the local governing body of a county or municipal corporation;

(7) subject to subsection (c) of this section, a motor vehicle used by a privately owned transportation company exclusively to provide transportation system services under a contract with the governing body of a county or municipal corporation or with a unit of State government;

(8) shuttle bus service operated by the University of Maryland, College Park Campus for students enrolled at the University of Maryland, College Park Campus and, in exchange for payment by a municipal corporation in which the University of Maryland, College Park Campus operates shuttle bus service, transportation service on the shuttle bus to residents of the municipal corporation; or

(9) transportation services that a nonprofit organization provides through the use of a volunteer driver and the volunteer driver's personal vehicle.