Northern Ave. bridge, and how government backs into bad decisions

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Northern Avenue Bridge, Boston Harbor, January 27, 2016.Alex Kingsbury

If $9.4 million in federal funding leads to the permanent demolition of the Northern Avenue Bridge, it’ll be a textbook study in how the government can back into decisions that future residents regret.

The Globe's Shirley Leung reported this week that US Representative Stephen Lynch secured some federal money to help design a replacement for the historic swing bridge connecting downtown Boston with the Seaport District. Lynch wants to remove the now-shuttered metal structure and start afresh. Noting that he recently had lunch with federal judges who worried about the effect of gridlock upon public safety, he also told Leung the new bridge should be open to cars.

When all the stars align correctly, both here and in Washington, great things can happen for Boston; burying the traffic-choked Central Artery famously required the exertions of former House Speaker Tip O'Neill. But it's also possible for bureaucratic prerogatives to align the wrong way — for iffy ideas to become reality without proper vetting.

Lynch and the judges presume that adding a vehicular connection will reduce traffic in the area. There is no evidence for this belief. Peter Furth, a professor of civil engineering at Northeastern, notes that the configuration of roadways around Northern Avenue limits its ability to alleviate traffic congestion in and out of the Seaport District. The bridge "has very little capacity for doing that," he said.

The only major recent study of transportation in the area — overseen by the group A Better City and released a year ago — didn't examine the possibility of general vehicular traffic on the bridge in any detail. "There was no home-run traffic benefit to the bridge," ABC president Richard Dimino told me. The discussion of vehicular use centered on accommodating emergency situations and, perhaps, transit buses. The overall study, he notes, focuses heavily on transit. (I asked Lynch's office for any studies supporting his position but didn't hear back by deadline.)

Preservationists don't dispute that parts of the current bridge are in bad shape. Quite the contrary; the city's inaction over the course of decades galls them, because it amounts to demolition by neglect. What worries them is that, under the auspices of protecting public safety, the city will demolish so much of the bridge that restoration becomes impossible — and a new vehicular bridge becomes an inevitability.

Mayor Marty Walsh's office says the plan is to remove all three spans of the bridge and some of the subsurface infrastructure. The historic truss system and the stone blocks surrounding the bridge's piers will be preserved "for future reuse."

Yet the easy way out for the city is to deem the old bridge hopeless. Whatever the city does will also have to pass muster with the Coast Guard and the Army Corps of Engineers, which have a say over structures in navigable waterways such as Fort Point Channel and clearly want to see some resolution. Nobody wants to pick fights with federal judges, not even on matters of transportation logistics or urban design. Or with a congressman who's bringing along a little money to get the process started.

But the real constituency for the project will be Bostonians for generations to come, and one more bridge choked with cars is no gift to them.