Md. Code, Transportation § 8–648

Any new or replacement storm drain cover, installed on a street or highway in the State, after January 1, 1980, shall consist of:

(1) Bars running perpendicular to the flow of traffic on the highway;

(2) A grating composed of intersecting bars; or

(3) Other designs approved by the Department of Transportation which meet safety design criteria as well as engineering and structural design demands.