Md. Code, Transportation § 21-1119

(a) In this section, “snow tires” means those tires that are in a good state of repair and that:

(1) Are normally designated by their manufacturer as snow tires;

(2) Are approved by the Administrator as meeting the standards of effectiveness required of normally designated snow tires; or

(3) Have antiskid patterns cut into the treaded surfaces to form bars, buttons, or blocks specially designed to give effective traction on snow or ice-covered highways.

(b) Subject to the prior approval of the governing body of the county affected, the State Highway Administration may designate, as it considers appropriate, any State highway, as defined in § 8-101 of this article, as a “snow emergency route”. When a highway is so designated, appropriate signs indicating this designation shall be placed along the highway.

(c) The Secretary of State Police or the Secretary’s representative may declare a snow emergency for all snow emergency routes as a whole or for any one or more snow emergency routes, as the Secretary or the Secretary’s representative considers necessary. The snow emergency shall continue in effect until the Secretary or the Secretary’s representative declares it to be no longer necessary.

(d) A person may not drive or attempt to drive a motor vehicle, other than a motorcycle, on any highway that is designated and appropriately signposted as a snow emergency route and for which a snow emergency has been declared and is in effect, unless the vehicle is equipped with chains or snow tires on at least one wheel at each end of a driving axle.

(e) A person may not park a vehicle on any highway that is designated and appropriately signposted as a snow emergency route and for which a snow emergency has been declared and is in effect. The Department of State Police or the police of any political subdivision of this State may have any vehicle parked in violation of this subsection towed from the highway.