Red Line Signal Work and Canterbury Street Bridge Detours Slow Thursday Morning Commute

Thursday Morning Commute Overview

Good morning, Boston. It is Thursday, March 12, 2026, and today marks the start of a significant new phase of transit work that will impact those relying on the Red Line. While overall highway traffic is moving at typical weekday volumes, several localized closures and long-term infrastructure projects are creating bottlenecks in South Boston, Roslindale, and the MetroWest area. Commuters are advised to check the latest schedules before heading out, particularly if using the Ashmont Branch or traveling through the Route 9 corridor.

MBTA Rail and Bus Disruptions

• Red Line Ashmont Branch: A new phase of the Columbia Junction signal modernization project begins today, March 12. Riders should budget an additional 10 to 15 minutes of travel time on the Ashmont Branch. This critical work involves repairing signals in the complex network of tracks near JFK/UMass and is expected to continue through the end of the month.
• Bus Route 77: Travelers on Route 77 (Arlington Heights to Harvard) are currently facing delays of up to 20 minutes due to heavy morning traffic. Additionally, the outbound stop at Massachusetts Avenue and Wendell Street has been moved 100 feet south due to ongoing construction in the area.
• Station Maintenance: The Harvard Square escalator (Mezzanine to Street) remains out of service for maintenance until Friday, March 13. At JFK/UMass, the escalator from the Ashmont platform to Columbia Road is also unavailable due to equipment maintenance.

Major Roadworks and Detours

• Canterbury Street Bridge Closure: The Canterbury Street Bridge in Roslindale remains closed to all vehicular traffic until further notice following a recent structural inspection. Drivers are being diverted onto a primary detour route utilizing Hyde Park Avenue, Cummins Highway, Rowe Street, and Brown Avenue. Heavy congestion is expected during peak hours on these secondary roads as they absorb the bridge's usual volume.
• Natick Route 9 and 27 Interchange: Construction crews have resumed work on the Route 9 and Route 27 interchange. Watch for lane shifts on Route 27 northbound as drainage pipe installation begins this week. Utility pole relocation is also ongoing along Route 9 between Linden Street and the Cochituate Rail Trail, resulting in periodic breakdown lane closures that may slow the eastbound commute.
• Somerville Complete Streets Project: Roadwork on Western Pearl Street in Gilman Square is currently active. This project includes sidewalk reconstruction and new protected bicycle facilities between McGrath Highway and Medford Street, causing localized lane restrictions.

Upcoming: St. Patrick's Day Impacts

While the South Boston St. Patrick's Day Parade is scheduled for Sunday, March 15, preliminary parking restrictions and traffic advisories are already appearing on Dorchester Avenue, Preble Street, and Damrell Street. The MBTA has confirmed that special shuttle bus services will be available this coming weekend to handle the influx of visitors, but regular commuters in the South Boston area should anticipate increased pedestrian activity and restricted neighborhood access starting later today.

For the smoothest commute today, we recommend using the Braintree Branch where possible if traveling toward downtown, as it is currently operating under normal service conditions.