Back in the late 1940s, transportation planners for the City of Boston and the Commonwealth of Massachusetts realized that the automobile was on its way to taking over the landscape. They sensed what was coming: Downtown Boston was in for a deluge of vehicles and congestion the likes of which the city hadn't known since trolleys and street cars overwhelmed downtown streets before America's first subway opened there in 1897.
The state's Department of Public Works (DPW) had a novel idea--a futuristic highway in the sky, an elevated road through the heart of downtown Boston with enough on- and off-ramps in the 1.5 miles between Kneeland and Causeway streets to get traffic within hailing distance of every neighborhood along the alignment.
The road was intended to work in concert with another highway, called the Inner Belt, that would have run around downtown Boston to the west (through the city's South End and Back Bay, across the Charles River to Cambridge, and and back to the downtown highway in Charlestown) to carry through traffic. It would be a system: Local traffic would use the elevated Central Artery downtown, and through traffic would bypass the heart of the city altogether.
Construction of the Central Artery made real a dream for a major thoroughfare in downtown Boston that dated back to 1909, when a special city commission recommended a 100-foot-wide road above a rail tunnel linking North and South stations. City and state planners couldn't reach consensus on the roadway and the idea languished. In 1930 came the first proposal to elevate the road, an idea whose time was delayed first by political disagreement and then by World War II.
Finally, in 1948, a master plan by the DPW (which later became the Massachusetts Highway Department) formalized the elevated highway plan, along with the Inner Belt, and construction started in 1950.
The dream of an elevated Central Artery/Inner Belt system began to sour, however, even before the first element (the elevated downtown highway) was finished. Construction progressed from the Mystic River (now Tobin) Bridge in Charlestown across the Charles River into downtown Boston and south to the Fort Hill neighborhood near what is now the Boston Harbor Hotel and International Place. But awarding contracts for the remainder of the downtown part of the highway-- from Fort Hill past South Station and Kneeland Street--was tied up in a dispute over the precise route of the highway.
In 1954 the DPW finally decided to extend the highway through Chinatown and the Leather District. But it was becoming clear that the portion of the elevated highway already built wasn't turning out to be the futuristic vision it was originally cracked up to be. The new Central Artery (the first section, from the Mystic bridge to North Street and the Sumner Tunnel, opened in October 1954) was ugly, it was a barrier between neighborhoods, and the land underneath wasn't terribly useful, with traffic flow confusing and inefficient. The DPW decided to sink the remainder of the highway into a tunnel from Congress to Kneeland Streets, which came to be called the Dewey Square or South Station tunnel.
The rest of the elevated Central Artery to Fort Hill opened in late 1956. The entire highway, including the Dewey Square Tunnel and the Southeast Expressway to Braintree, opened on July 1, 1959. The downtown Central Artery comfortably carried about 75,000 vehicles a day in 1959, but it's profusion of on- and off-ramps (27 between Kneeland and Causeway Streets), and the lack of merge and breakdown lanes, made the road a challenge to navigate from the outset. The numerous access points were thought to be essential to prevent traffic from overwhelming surface streets. And highway planners hoped that construction of the Inner Belt would alleviate some of the difficulties on the downtown part of the road.
The elevated highway progressed through downtown Boston from north to south. Planners decided to put the southern portion from the Fort Hill neighborhood past Congress Street and Dewey Square to Kneeland Street in a tunnel, because they realized that the elevated portion of the highway was too obtrusive and disruptive in the midst of downtown life.
But the Inner Belt was never built. Residents in areas along the path of the highway, recalling the swath cut through downtown's North End, Financial District, Waterfront, and Chinatown neighborhoods by the elevated Central Artery (more than 1,000 structures were demolished, and more than 20,000 people lost their homes), rose up in opposition to the Inner Belt, and the project was canceled.
So the elevated Central Artery in downtown Boston today carries the local traffic it was designed for, and the through traffic it was not. The congested, deteriorating highway carries more than 190,000 vehicles a day with an accident rate four times the national average for an urban Interstate. It simply must be replaced. It has a bumper-to-bumper traffic jam for six to eight hours every day, with projections of a 15-to-16-hour jam-up by 2010 if nothing is done to fix it. It can't be expanded where it sits, because to add a lane would mean taking a lane during construction, which would make a terrible traffic situation disastrous to the city.
The entire elevated Central Artery, including the Southeast Expressway to Braintree, opened in 1959, comfortably carrying about 75,000 vehicles a day. Today, the elevated Central Artery carries more than 190,000 vehicles a day with a bumper-to-bumper, stop-and-go traffic jam up to eight hours a day. The only place to build a new highway is directly underneath.
The city can't plow down another neighborhood, can't pave over the Boston Common, can't build a new road over the waterfront. There is only one place to build a new Central Artery, and that is directly beneath the elevated highway. The I-90 Ted Williams Tunnel--the third tunnel under Boston Harbor--and the two-bridge Charles River Crossing complete a modern configuration of the highway system that was planned more than half a century ago, distributing traffic rationally through and around downtown Boston.
Information provided by the Central Artery/Tunnel Project through the Big Dig website.
