Highways for Habitats #17: Big Dig, Boston

Big DigTransportation planning is tough.  Roads have to serve a number of (sometimes competing) purposes.  Roads whose primary purpose is moving people and goods quickly through a community often have a detrimental effect on the communities they bisect (see: the history of freeways in Detroit).  Take state trunk lines for example, which you can recognize because they’re usually twice as wide to cross as the other roads in a neighborhood, and, of course, highways and interstates.  We’re currently running a series of posts featuring creative solutions from around the globe to make these roads – roads that must run through communities – also work to serve those communities.  Check out more about our inspiration here.

The John F. Fitzgerald Expressway, commonly known as the Central Artery, was built in the 1950s as a mostly elevated freeway through downtown Boston.  It became known as “the distressway” and “the largest parking lot in the world,” due to the massive course it sliced through neighborhoods, which displaced 10,000 residents and required the demolition of 1,000 buildings.

By the 1990s, the number of cars using the interstate had increased by 2.5 times, making the traffic congestion on the Central Artery unbearable; one prediction estimated it would reach 16 hours of traffic jams per day in 2010—in other words, essentially constant traffic congestion.  The 200,000 cars running through the city daily significantly contributed to noise and air pollution, and the disconnect created by the elevated structure between neighborhoods and districts was an issue for many.  For these reasons Boston undertook one of most ambitious freeway projects in the world.

Between 1991 and 2006, the Central Artery was relocated into a higher capacity 3.5-mile tunnel below-ground in a project known as the Big Dig.   Many innovative solutions in civil engineering were developed to make the project a success.  In order to fit the freeway below ground, it had to sit only inches from the subway tunnels below it.  Engineers developed an unprecedented program to freeze the earth to stabilize Boston’s historic soils and prevent erosion.  When completed it was deepest underwater connection in North America, and the Leonard P. Zakim Bunker Hill Memorial Bridge was constructed to cross the Charles River as the world’s widest cable-stayed bridge.

Moving the freeway opened up a 27-acre parcel of land to redevelopment.  Streets that once came to a halt at the freeway were rejoined, linking communities once more.  The Rose Kennedy Greenway was developed as a landscaped boulevard surrounded by three major parks, many neighborhood parks and cultural institutions.  New development, like housing units and other smaller-scale growth, grew.

While the Big Dig is not without its cautionary tales and continued problems – like leaks, design flaws, and exorbitant expenses – the benefits seem to outweigh the costs.  Congestion in the city has significantly reduced.  The Financial District, the waterfront, the historic North End neighborhood, and others are now unified by a spacious greenway.  As of 2008, commercial property values rose by 79% since the project began.  With project completion in 2006, $5.3 billion worth of private investment in new development within a 5-minutes walk was completed or in construction phases, including 4,200 housing units.

The United States’ largest and most complex transportation project ever resulted in city betterment and economic growth.  Sometimes, you just have to go big.


Photo from Arden on flickr.com

  • Kelsey

    Love this solution. If only Detroit had the money, underground portions of freeways would be a great option!