Among the road changes targeted by the state are turning the freewheeling Bourne Rotary on the Cape side into a more conventional interchange with traffic lights at three intersections; simplifying the rotary on the mainland side of the Bourne, called Belmont Circle, while improving access to the bridge itself, and to Route 25 westbound; and eliminating the merge at the base of the Sagamore Bridge in Sandwich that causes lengthy backups on Route 6, by moving the on-ramp more than a half-mile back up the highway.

The Massachusetts Department of Transportation this week proposed adding or moving several highway ramps, reconfiguring rotaries, and creating signalized intersections around the Bourne and Sagamore bridges. The more than $200 million in work hinges on an even bigger project under consideration by the federal government — the $1 billion overhaul or complete replacement of the bridges themselves.

Just in time for the busy summer season, state officials have released a long-awaited plan to dramatically reconfigure the traffic-choked roads around the two aging bridges that daily funnel tens of thousands of vehicles on and off Cape Cod.

Officials say the upgrades could knock as much as 15 minutes off the delays on a summer Saturday, and make the daily commute during the rest of the year much faster; all told, the state estimates the changes would save vacationers and 34,000 daily commuters about 900,000 hours a year.


“This is very encouraging,” said Wendy Northcross, chief executive of the Cape Cod Chamber of Commerce, which has been lobbying to get both the bridges and connecting roads fixed. “It’s moving through the channels it needs to move through to become reality, and that’s good news.”

In its report, the state also tacitly endorsed an outright replacement of the two 84-year-old bridges, over repairing them. The road work “assumes” full replacement of the two bridges, said MassDOT project manager Ethan Fritlin. Several improvements would be possible only if the bridges are completely rebuilt.


The Army Corps of Engineers, which built and owns the two spans, is expected to decide this summer on a course of action for the bridges, with a final go-ahead due this winter.

However the state plan offers a glimpse of what new bridges might look like. It describes spans 138 feet wide — nearly triple their current width — with a new third lane in each direction for vehicles merging on and off the roadway. There would also be much wider paths for cyclists and pedestrians than the existing 5-foot sidewalks.

On an average summer day, 122,400 vehicles cross the two bridges. By 2040, the state expects daily traffic to grow 27 percent in the summer, and 32 percent during the rest of the year — and most of that additional traffic will be on the Sagamore Bridge. In the meantime, lanes are frequently closed for repairs above and below the roadway, making already considerable traffic backups even worse.

The increasing numbers highlight the need to act swiftly, said Marie Oliva, president of the Cape Cod Canal Region Chamber of Commerce.

“It’s not just businesses. It’s residents, it’s everybody,” she said. “We’re impacted year after year, and year after year it seems to be getting worse.”

The challenge is getting attention and money from Washington, D.C. Cape business leaders have been closely watching talks around a federal infrastructure bill that could provide funding for such a huge endeavor, and were encouraged last week when Governor Charlie Baker went to Washington in support of the legislation.


But the fragility of those talks was on display Wednesday, when President Trump walked out of a meeting with top congressional Democrats at which they were scheduled to discuss the infrastructure bill. Trump said he wouldn’t negotiate on road and bridge spending until Democrats agree to call off investigations into his finances and potential campaign ties to Russia.

“I was a lot more optimistic a couple of hours ago,” Northcross said Wednesday afternoon. “This project just needs doing.”

The Sagamore Bridge. David L. Ryan/Globe Staff/file/Globe Staff

Some members of the state’s congressional delegation are trying another tack. Representative Bill Keating and Senator Ed Markey this week filed legislation that would set aside $1 billion a year to improve critical emergency evacuation routes, including the Cape bridges.

“The Bourne and Sagamore bridges over the Cape Cod Canal are especially vulnerable, as they have long exceeded their working lives,” Keating said. “And yet, they remain the only lifelines for the residents of Cape Cod in times of emergency.”

Massachusetts, meanwhile, has earmarked $10 million in state money for design work for the approaches. And if federal funds for the bridges themselves prove slow in coming, some of the road work can still move forward on its own, said Fritlin, the state project manager.

The road improvements will make a difference, he said, but a solution to the Cape’s longstanding traffic conundrum requires a massive, coordinated effort between the state and federal governments.


“If there were easy fixes, we would have done them by now,” he said.

The approach to the Sagamore Bridge on a July Sunday in 2013. Matthew J. Lee/Globe staff/file

Tim Logan can be reached at tim.logan@globe.com. Follow him on Twitter at @bytimlogan.