A proposed tunnel that would carry cyclists and joggers on the Capital Crescent Trail beneath Wisconsin Avenue at the Bethesda Purple Line station may be delayed.

The tunnel that would carry runners and cyclists on the Capital Crescent Trail beneath Wisconsin Avenue may not be ready when the Bethesda Purple Line station opens in approximately two years.

The proposed budget by Montgomery County Executive Marc Elrich includes no money for the tunnel, which would be funded by the county, adjacent to the state’s light-rail project.

Daily construction is underway along Wisconsin Avenue and nearby streets for the Bethesda station and rail infrastructure.

While the tunnel has been promised for years as a way for cyclists, runners, and walkers to avoid having to cross busy Wisconsin Avenue at street level, the county said construction costs have continued to rise.

County spokesman Neil Greenberger said funding for the tunnel was not included in the capital improvement plan Elrich announced this week.

“The scope of the project changed as it was further studied,” said Greenberger. “It needed to be a longer tunnel than originally believed, and that boosted the cost significantly.”

Greenberger said funding for the project “could be added in the future, and we will continue to study alternative ways to build it at a more reasonable cost.”

Without funding, progress on the tunnel would be delayed, disappointing bicycle advocates who say the feature has been promised for years.

In the meantime, the county has funded a surface trail that follows 47th Street at Elm Street Park. Cyclists and others would cross Wisconsin Avenue at a light, and cross Bethesda Avenue, to rejoin the trail at Woodmont Avenue.

Trail advocates have said the tunnel is more than just a convenience for people traveling under their own steam — it is part of the region’s trail network, which can help minimize the number of cars on local roadways.

The Capital Crescent Trail, when completed, will provide a continuous route from Silver Spring to Georgetown.

The 16-mile line between Bethesda and New Carrollton will open in stages — in Prince George’s County by the end of 2022, and in Montgomery County in mid-2023.