Maryland Code, Transportation § 25-114

(a) In this section, “checkpoint” means a predetermined fixed location at which a police officer stops a motor vehicle or a specific sequence of motor vehicles to conduct safety inspections, inspect drivers' licenses or registrations, or evaluate drivers for impairment.

(b) Except as provided in subsection (c) of this section, a police officer at a motor vehicle checkpoint may not target only motorcycles for inspection or evaluation.

(c) A police officer at a motor vehicle checkpoint established as part of a police search or investigation may target motorcycles as appropriate.