Ninth Street Tunnel repair plan narrows a downtown Washington route into 2027

Washington’s District Department of Transportation scheduled long-term lane restrictions in the southbound Ninth Street Tunnel beginning September 28, 2026, as crews repair damage sustained earlier this year.

The September 23 advisory sets June 30, 2027, as the planned end of continuous outer-lane closures. The affected route starts at Constitution Avenue and runs beneath the National Mall.

DDOT’s sequence closes the outer left lane first, followed by the outer right lane. The center lane may also close during six-hour off-peak work periods, leaving one lane available at those times.

That sequence makes the changing lane arrangement a practical concern for regular users: the lane available during one phase will not necessarily remain available during the next. The advisory describes a staged repair operation rather than a full tunnel shutdown.

The notice does not provide a construction budget or detailed explanation of the earlier damage. Its dates describe DDOT’s announced traffic plan; they are not independent confirmation that each restriction began on schedule. Travelers should check the department’s current advisories before using the route.

Sources reviewed September 29, 2026. Historical photograph of the Ninth Street Tunnel approach, September 12, 2019; not the 2026 repair work. Photo: Famartin, CC BY-SA 4.0. Original unaltered; resized or cropped display versions remain under the same license.