The District’s Circulator bus network is set for a major expansion, one that could add six new routes, extend four others, and leave only one existing route unchanged while bringing Circulator service to currently unserved parts of town as far-flung as the National Cathedral, Brookland, and Congress Heights.

The District Department of Transportation released its 2014 Circulator Transit Development Plan for public comment today, a comprehensive report that analyzes the successes and shortcomings of the existing Circulator network and makes the case for a series of new routes. Some of the proposals simply add capacity and connections to neighborhoods already served by Circulator routes, while others aim to expand the network, which once served just the central part of the city, to new areas.

“The District has recovered from decades of declining population and is growing again,” DDOT acting director Matt Brown (who just hours after the plan’s release lost his “acting” prefix when the D.C. Council voted to confirm him) wrote in the report’s foreword. “Neighborhoods across the city are reemerging and adding people, jobs, and businesses. This rebirth has created challenges for the District’s infrastructure, and we need to make informed transportation investments that will support our growth and further strengthen our city. The DC Circulator will play a key role in meeting this transportation need only by continuing to provide a reliable, efficient, and appealing transit option.”

The plan breaks the changes into three phases. The first phase, which would take place between 2015 and 2017, would see the addition of the National Mall route (already scheduled to begin in 2015) and a line between the McPherson Square Metro station and the National Cathedral. That phase would also extend the Dupont-Georgetown-Rosslyn line to U Street and Howard University; extend the Potomac Avenue-Skyland line to Congress Heights; and extend the Georgetown-Union Station line to the National Cathedral. (That final change would be eliminated once the McPherson-National Cathedral route begins.) The second phase, between 2018 and 2020, would add a line between the convention center and the Southwest Waterfront and one in NoMa, with a route to be determined. The final phase, slated for implementation between 2021 and 2024, would bring a connection between Dupont Circle and the Southwest Waterfront and a route through Columbia Heights, Brookland, and NoMa.

Like any good transportation plan, this one gets in a few political digs. Three of the proposed route extensions—-the Georgetown-Union Station one to the cathedral, the Skyland one to Congress Heights, and the Union Station-Navy Yard one to the Southwest Waterfront—-“are expected to fall short of several key Circulator performance metrics,” the report states, but are included in the plan because the D.C. Council voted to fund them. According to the report, the Union Station-Navy Yard extension to the Southwest Waterfront would require by far the largest subsidy per passenger—$11.80 for each one, based on projected ridership. By comparison, extending the Rosslyn-Georgetown-Dupont line to U Street and Howard University would require a subsidy of just $1.86 per passenger. None of the lines is expected to recoup even half its costs through fares, which are expected to rise from $1 to $1.50 for SmarTrip users and $2 for cash payers.

Even after shedding its National Cathedral extension, the Georgetown-Union Station line will overlap with the National Cathedral-McPherson Square line for much of its route through Georgetown and downtown. The DDOT report explains that this segment of the existing Georgetown-Union Station line is overcrowded at peak times, and that the redundancy will allow for better service. DDOT aims to maintain 10-minute headways between Circulator arrivals at any given stop, a target it has struggled to meet, with one in five arrivals taking 15 minutes or longer.

The Circulator lines have grown popular for their simple routes, limited-stop service, and modern buses, serving 5.6 million riders last year along five routes. The proposed expansion aims to bring this service to more parts of the city. But it could also undermine some of the things readers have come to like about the Circulators, making it harder to discern routes in areas suddenly served by multiple lines and creating more convoluted paths for some lines, such as the proposed T-shaped line from Columbia Heights to NoMa via Brookland and the winding 12.6-mile route through Skyland to Congress Heights. The higher subsidies required for some of these routes could also bring political blowback.

Today’s plan follows the 2011 DC Circulator Transit Development Plan, which stipulated than DDOT release an updated plan every three years. The plan is subject to public comment prior to final approval.

Here are maps of the proposed new routes and extensions:

And here are the routes that DDOT considered and rejected:

Maps and charts from the DDOT report