Md. Code, Transportation § 21–1205

(a) Each person operating a bicycle or a motor scooter at a speed less than the speed of traffic at the time and place and under the conditions then existing on a roadway shall ride as near to the right side of the roadway as practicable and safe, except when:

(1) Making or attempting to make a left turn;

(2) Operating on a one-way street;

(3) Passing a stopped or slower moving vehicle;

(4) Avoiding pedestrians or road hazards;

(5) The right lane is a right turn only lane; or

(6) Operating in a lane that is too narrow for a bicycle or motor scooter and another vehicle to travel safely side by side within the lane.

(b) Each person operating a bicycle or a motor scooter on a roadway may ride two abreast only if the flow of traffic is unimpeded.

(c) Each person operating a bicycle or a motor scooter on a roadway shall exercise due care when passing a vehicle.

(d) Each person operating a bicycle or a motor scooter on a roadway may walk the bicycle or motor scooter on the right side of a highway if there is no sidewalk.