The Boston Big Dig and the Problems with Complex Projects

Big infrastructure projects run into a lot of roadblocks primarily because of unforeseen technical and financial challenges and poor project management, but that does not mean we should not try and tackle them sometime. Any major project that comes to mind, the Space Shuttle, the James Webb Telescope or the Channel Tunnel, was faced with these aforementioned problems. One example that I’d like to focus on is the Boston Big Dig the most complex highway project ever undertaken in the United States has served its purpose to alleviate an eyesore from Boston and reduce traffic congestion, but the project was plagued by massive budget overruns, missed deadlines and corruption. Initially budgeted for 2.8 billion dollars, the budget for the project swelled to 14.6 billion, and some estimates place the final cost at 22 billion dollars.


Before the “Big Dig” the central artery (I-93) existed as a raised expressway highway running north-south through the center of Boston, in 1959 the highway carried 75,000 vehicles a day by the 1990s that number grew to almost 190,000. As the number of vehicles would only increase something needed to be done, then Secretary of Transportation Frederick Salvucci and Bill Reynolds both MIT graduates proposed moving the entire expressway underground. Salvucci believed that putting the highway underground would reconnect downtown to the waterfront and increase the amount of green space in the city.

The project consisted of several segments:

  1. The Ted Williams Tunnel a 1.6 mile tunnel beneath Boston Harbor which was completed on time and on schedule, connects South Boston to Logan Airport
  2. The I-90 Extension entailed bringing the Massachusetts Turnpike underneath the Fort Point Channel and South Boston before connecting with the Ted Williams Tunnel
  3. The Thomas P. O’Neill (Former Democratic Speaker of the House who championed the project) a 1.5 mile tunnel that connects I-93 Zakim Bunker Hill Bridge
  4. The Zakim Bunker Hill Bridge replaced a six lane double-decker bridge (the bridge is now an ionic part of the Boston skyline)
  5. The Storrow Drive Connector Tunnel and Bridge and carries traffic to and from the famed Storrow Drive


During construction many engineering challenges posed a challenge such as building the tunnel without effecting the structural of the above roadway. The tunnel also had leaking issues due to subcontractors failing to remove gravel and other debris before concrete was poured. After the project was finished in December 2007 it was discovered that substandard materials were used that led to a fatal ceiling collapse and it has been recently revealed that the wrong material had been used for light fixtures leading to galvanic corrosion.

From my personal experience as an engineer, I can tell you few products are delivered on time which is why release dates are closely guarded secrets. Computer models guide engineers and planners, but they cannot predict how things will behave once construction or assembly starts with real materials. While cost is something we work toward reducing, managing cost is not up to the engineer, that’s up to the project manager and the financial analysts in fact there have been numerous occasions where as an engineer, I’ve stated the line to a client, “I cannot discuss cost, I’m not authorized to do so.” Part of the problem with defining budget and controlling costs is that many large projects are often under-priced to make them attractable to another party, which is what happened in the case of the Big Dig. Sometime certain costs can’t be taken into account; numerous unusual problems appeared during construction, which is very similar to the electronics industry where unusual problems appear due to uncharted technical territory.  That being said the formula for a project is more complicated such that Y=Output and X= # known variables, X1…Xn, but the problem is there are several unknown variables Z1…Zn that will eventually slow down a major project.

The key problems in the Big Dig seem to be accountability, lack of planning for contingencies and oversight, the use of so many contractors made it hard to account for the types of materials used and assuring the same quality of work by each contractor.


Personally, I think the Big Dig has served its purpose as innovative transportation project and establishing Boston as a world-class city with world class infrastructure. Every time, I drive toward Boston I know that I’m approaching my destination once the Zakim bridge is in view, and then I descend into the tunnel and look for my exit. I enjoy walking on parts of the Rose Kennedy Greenway where the previous raised expressway existed.


Some Articles on the Big Dig:


4 thoughts on “The Boston Big Dig and the Problems with Complex Projects”

  1. Nice article! I had no idea that there were so many problems with the construction of the tunnel. This was really a massive project. The before and after landscapes are dramatically different, and I appreciate the after landscape. It was an ambitious undertaking of a good idea that had many risks and a big budget, but I think it was worth it.

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