The Maryland State Highway Administration has developed potential plans for a signed detour route and other measures to help drivers who will not have access to the Carroll Avenue bridge in Takoma Park when it goes under construction.

The bridge, which passes over Sligo Creek Parkway and Sligo Creek, will be closed for about 12 months of a roughly 18-month construction project, according to administration officials.

The project does not yet have a start date but will not begin until a nearby project on New Hampshire Avenue is completed, said Maurice Agostino, the state administration’s project manager for the Carroll Avenue bridge.

As it stands in the early stages of the planning process, the signed detour route for cars would follow Philadelphia, Flower, Maple and Maplewood avenues, said Josh Smith, a project manager for consulting firm Sabra, Wang & Associates Inc. at the Jan. 28 Takoma Park City Council meeting.

Diverting the full volume of traffic to any one alternate route would be “problematic,” Smith said.

Therefore signs also would be put up to generally encourage the use of alternate routes, he said.

The assumption, Smith said, is that some drivers will use Sligo Creek Parkway, which was not included in the proposed route because the road is closed to vehicles on Sundays.

“We recognize that people will know the area, know other ways to go,” Smith said.

Daryl Braithwaite, the city’s public works director, said she hopes the parkway’s Sunday ban on vehicle traffic will be temporarily lifted to allow the road to serve as the main alternate route.

Though it is currently in place to allow clear passage for bikers and pedestrians, “It’s hard not to let [the ban] go,” Braithwaite said, as the road provides a shorter route.

The administration also presented concepts for temporary measures including a signal at Washington Adventist Hospital and Sligo Creek Parkway; a signal at Maple Avenue, Sligo Creek Parkway and Hilltop Road; a three-way stop at Old Carroll Avenue and Sligo Creek Parkway; and a three-way stop at Maplewood Avenue and Flower Avenue.

Buses and trucks would detour along two other routes that would not be marked by signs: buses would travel on Sligo Creek Parkway and trucks would use University Boulevard and Piney Branch Road, Agostino said.

The concepts also include a temporary pedestrian bridge built across Sligo Creek at the same level of the current bridge and tied to surrounding sidewalks.

The next step is a public meeting to discuss the administration’s ideas, which will be scheduled for sometime in the spring, Agostino said.

“There’s lots of opportunity for public input at this point,” he said.

Agostino said during the council meeting that the bridge built in 1932 has been deemed “structurally deficient.”

“It’s an early warning sign to engineers that it’s time to work on it,” Agostino said.

The project will necessitate closing the entire bridge due to its structural configuration, he said, and includes replacing the bridge’s driving surface and replacing and rehabilitating floor beams that support the bridge.

lpowers@gazette.net