What is a one-way couplet?
A one-way couplet is a pair of one-way streets directing vehicles in opposite directions. In downtown Baltimore, Charles Street (which is only northbound) forms a one-way couplet with St. Paul Street (which is only southbound). Often in a downtown street grid, each one-way street in a couplet is a block away from the other street. One-way streets are used primarily to improve traffic flow in densely developed areas. The same principle can be used for a transit line. Where space is limited, trains heading east could be located on one street with trains heading west on a nearby street. One-way transit couplets are options at several points in the Red Line study area: along Baltimore and Lombard Streets, Eastern and Fleet Streets, and Fleet and Aliceanna Streets. For the Baltimore-Lombard one-way couplet, the Red Line eastbound train (or busway) would be located on Baltimore Street, traveling in the same direction as other traffic on Baltimore Street. Similarly, the Red Line westbound tra
