Maryland Code, Transportation § 13-102

(1) A vehicle owned and used by the United States, unless it is registered in this State;

(2) A new vehicle owned by a manufacturer or dealer and held for sale, even though incidentally moved on the highway or used for purposes of testing or demonstration or used as allowed under § 13-621 of this title;

(3) A vehicle used by a manufacturer only for testing;

(4) A vehicle owned by a nonresident of this State and not required by law to be registered in this State;

(5) A vehicle regularly engaged in the interstate transportation of people or property and for which a currently effective certificate of title has been issued in another state;

(6) A vehicle moved only by human or animal power;

(7) A bicycle, except for a moped;

(8) A vehicle in which interest has passed to a secured party on default of the owner;

(9) Farm equipment;

(10) Special mobile equipment;

(11) A self-propelled invalid:

(12) A trailer, other than a camping trailer, rated by the manufacturer as having a gross vehicle weight of 2,500 pounds or less; or

(13) An off-highway recreational vehicle purchased before October 1, 2010.