The Sumner Tunnel, a vital transportation link for residents and commuters in Boston, will undergo a one-month closure starting on July 5, state transportation officials announced on Tuesday. This closure aims to facilitate much-needed repairs to the aging 90-year-old structure.

Originally, the closure was planned to span two months, but officials have managed to shorten the duration after making progress during weekend shutdowns this spring. However, when the tunnel reopens in early August, weekend closures will continue until at least October, possibly even extending until Thanksgiving, warned Highway Administrator Jonathan Gulliver.

With the tunnel carrying approximately 40,000 vehicles per day from East Boston into downtown, the closure is expected to cause significant traffic congestion and headaches, particularly for residents and travelers in the East Boston area, including those accessing Logan International Airport.

Acknowledging the potential impact, Gulliver advised individuals traveling to the airport to allocate extra time for their journey. He emphasized that heavy traffic should be anticipated, not only during peak travel hours but even during off-peak hours as well.

To minimize the inconvenience for commuters and residents, transportation officials urge the use of public transportation whenever possible. Affected travelers can expect the adjacent Callahan Tunnel, which carries vehicles in the opposite direction from Boston's North End to East Boston, to remain open throughout the summer.

Last year's two-month closure of the Sumner Tunnel prompted the Massachusetts Bay Transportation Authority (MBTA) to implement various mitigation efforts. This summer's closure will see similar benefits in place, including fare-free service on the Blue Line, free or reduced ferry rides, discounted commuter rail trips on the Newburyport/Rockport line, fare-free service on select buses in Chelsea, and reduced parking rates at some MBTA lots.

The MBTA estimates that during the previous tunnel closure in 2023, 10% of diverted drivers opted to take public transit, while 77% chose alternative routes and 14% did not travel. Notably, public transit saw a substantial increase in ridership during weekends, with a 13% rise in Blue Line ridership, a 23% increase in Orange Line ridership, and a significant 41% jump in Newburyport/Rockport commuter rail ridership.

Despite the potential benefits, the MBTA's efforts to provide additional services during highway projects have contributed to its ongoing financial struggles. The agency has yet to receive reimbursement from the state for the $6.1 million spent on mitigation efforts during last year's tunnel closure, and it remains uncertain whether they will be reimbursed for this summer's expenses. Secretary of Transportation Monica Tibbits-Nutt stated that the agency is still "working through that" and expects to have an answer in the coming months.

As the MBTA faces an estimated $628 million operating budget deficit by July, escalating to nearly $900 million by 2028, concerns over funding to close the projected budget gap have arisen. Both governor Maura Healey's proposed funding for the upcoming fiscal year and the Massachusetts House of Representatives' proposal fall short of providing sufficient financial support.

With significant traffic disruptions expected during the Sumner Tunnel closure, officials have confirmed that alternative detour routes will be adjusted based on lessons learned from the previous closure. Despite the inconveniences caused, officials believe that the shorter closure period will expedite the renovation process, allowing for a safer and more efficient tunnel in the long run.

As the closure approaches, transportation authorities strongly urge travelers to plan their trips accordingly and utilize public transportation options whenever feasible.