Md. Code, Transportation § 21–1113

(a) A person may not place any structure, building, or vehicle on a highway to sell or display any produce or merchandise if it constitutes a traffic hazard.

(b) In Prince George’s County, a person may not sell or display any produce or merchandise on State highways in a manner that constitutes a traffic hazard.

(c) On the order of any police officer, the person shall:

(1) Remove the structure, building, or vehicle described under subsection (a) of this section; or

(2) Cease any activity prohibited under this section.