A constellation of transportation planners, elected officials and community groups embarked Wednesday on a campaign to think about a massive project coming into focus on the horizon: replacing the Tobin Bridge.
Over the next 18 months, a state working group will examine options to succeed the 74-year-old bridge that connects Chelsea and Boston's Charlestown neighborhood. Its scope is broad, and will focus on threads such as how to balance vehicular traffic with public transit and the best way to minimize upheaval during construction.
The eventual project is all but certain to be enormously disruptive, given the tens of thousands of vehicles — 87,000 per typical weekday last year — that rely on the bridge that carries Route 1 over the Mystic River. But changes are also years away: the planning study alone will not be complete until the summer of 2026, according to a slide presented Wednesday.
"The Tobin Bridge is a very large structure. It's very integrated in the regional transportation network. I think we can call the eventual replacement 'complex,'" said Patrick Snyder, who works in MassDOT's office of transportation planning. "We're working on this now to get an idea of: OK, what are the options that come down the line when we do need to construct it, and at that point, think about funding and how we fund that construction? Part of this planning study right now is going to think about: what are those funding sources?"
One attendee asked at the working group's first meeting Wednesday whether officials were committed to a successor bridge or might consider a tunnel instead.
"That's what we're here to figure out," Snyder replied. "We are basically here to come up with any and all ideas and then narrow those down to what makes sense, what the community supports, what's feasible. That's part of the process."
Participants floated several different priorities they hope to see addressed in the eventual bridge replacement, including efforts to reduce the number of single-occupancy vehicles on the road and avoiding eminent domain property-taking for any work.
The state has several other major infrastructure projects underway or in the pipeline. Work is almost complete on an effort to rehabilitate the Sumner Tunnel, which involved shuttering the throughway for weeks at a time this summer and last. Officials also continue to plan for a megaproject in Allston that would replace an aging viaduct with highway, rail and pedestrian infrastructure all side by side near the Charles River.
For some, the specter of the Tobin Bridge replacement brought to mind another gargantuan project: the infamous Big Dig, which buried highways and added green space to Boston but ran years and billions of dollars over budget.
But for Charlestown Rep. Daniel Ryan, replacing the bridge over the Mystic might be the "logical next step" from that history.
"The best example, I think, maybe nationwide for improvements to air quality, health and mobility, and as much as the cost overruns were, [was] the Big Dig," Ryan said during Wednesday's meeting, describing the former elevated Central Artery as "a monstrosity through our neighborhoods."
"You just walk down the Rose Kennedy Greenway, having lived with what was there before and understanding it, running underneath the old green monster there, the old highway, you'd have to dodge pigeon poop the entire way getting home from school in the North End because you were running underneath the world's largest pigeon coop, which was running through the heart of Charlestown," he added. "This is, I think — we're going to need a ton of federal funding. We have to remind people that took 25 years of planning and eventually, it came to fruition."