From the previous link
Traffic Laws for Bicyclists
Maryland law provides for the right-of-way of bicyclists, just as it does for the operators of motor vehicles. Bicyclists also have the duty to obey all traffic signals, signs and pavement markings, just as do drivers.
Riding in Traffic Lanes and on Shoulders
A bicyclist riding slower than the speed of traffic is confined to the right hand through lane (much the same way as a slow moving vehicle is)
and as close to the right side of the road as is safe. A bicyclist can move further left to:
Make or attempt to make a vehicular style left turn
Pass a stopped or slower moving vehicle
Avoid pedestrians or road hazards.
This ride-to-the-right provision does not apply when operating in a lane that is too narrow for a bicycle to travel safely side-by-side with another vehicle within the lane. The provision also does not apply where the right-hand lane is a turn lane, or the bicyclist is operating on a one-way street.
A bicyclist riding at the speed of traffic can operate in any lane, just as any other vehicle can..Where there is not a bike lane, a bicyclist may also use the shoulder of the roadway.
Bicycles may not be ridden in the travel lanes of any roadway where the posted maximum speed limit is more than 50 miles an hour; however, bicycles may be operated on the shoulder of these roadways.
Bicycles may not be operated on expressways (access-controlled freeways and interstate highways), except on an adjacent path or facility approved by the State Highway Administration.
Greg's complaint dealt, in part, with the "outriders" who elected themselves wardens and rode in the middle of the lane.