The cheapest form of public transportation in Washington is the D.C. Circulator, at just $1 a ride. For Capitol Hill staffers and visitors, one Circulator route goes to Union Station, the Capitol, the Supreme Court and the Library of Congress.

But the District Department of Transportation’s 2017 Transit Development Plan Update includes a proposed modification of that route that would eliminate the Capitol Hill stops.

The update found that the route in question, Union Station to Navy Yard Metro, has the lowest ridership overall of the six Circulator routes. 

The public has until Oct. 13 to comment on the proposed changes, a process that occurs every three years, through surveys available on Circulator buses. A public hearing will be held after that.

Employees of the Library of Congress have already spoken out about the potential loss of service. As it is laid out now, the Circulator stops at Independence Avenue and Second Street SE near its building.

“The ending of DC Circulator Bus service to the Library of Congress will have a profound adverse impact on Library staff and visitors, especially people with disabilities,” the Library of Congress Professional Guild said in a news release.

Senior citizens and people with disabilities pay 50 cents per Circulator ride.

The LOC guild noted that without this route, the public transportation alternatives to getting from Union Station to the library are taking the 97 Bus, which does not operate on the weekends and costs $2 a ride, or take the Metro Red Line to Metro Center and switch to the Orange/Silver Line to Capitol South, which costs $2.25 a ride.

The Union Station to Navy Yard Metro route operates weekdays from 6 a.m. to 9 p.m. in the summer and 6 a.m. to 7 p.m. in the winter. It also operates on Saturdays only in the summer and on Sunday when the Washington Nationals have a home game.

The proposed modification would take out the portion of the route around Capitol Hill and add stops along the Southwest Waterfront to serve the new District Wharf development. The new route would terminate at the Eastern Market Metro station, instead of the Union Station Metro station, and extend to the L’Enfant Plaza Metro station, serving the new International Spy Museum and the Museum of the Bible.

DDOT’s update said the route had 17 boardings per revenue hour in 2014, 2015 and 2016, compared to the Circulator’s target of 25 boardings per revenue hour.

“Several challenges were identified on the route, including low ridership, and trip times uncompetitive with Metrorail trip times,” the DDOT said in response to a request for a statement.

The LOC guild is asking its members to comment before Oct. 13.

“The union represents 1,500 professional library employees, some of whom are disabled and ride the Circulator and who are concerned because it’s going to be difficult for them to get to work,” guild president Saul Schniderman said.

DDOT is also encouraging Washingtonians to give their input.

“This is a proposal and we invite the public to share their input to help inform our decision making process,” the department said.

Changes approved in a public hearing would go into effect in 2018.

The Circulator first began operating in July 2005 and added the Union Station to Navy Yard Metro route in March 2009.