Infrastructure Past, Present, and Future Casebook/Big Dig

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This casebook is a case study on the Big Dig by Shaheer Malik, Evan Price, Maeen Aljaieed, and Gurfateh Singh as part of the Infrastructure Past, Present and Future: GOVT 490-004 (Synthesis Seminar for Policy & Government) / CEIE 499-001 (Special Topics in Civil Engineering) Spring 2022 course at George Mason University's Schar School of Policy and Government and the Volgenau School of Engineering Sid and Reva Dewberry Department of Civil, Environmental, and Infrastructure Engineering.

DISCLAIMER: The information presented in this wikibook is for academic purposes only and has no particular goal beyond presenting what has been learned. Any views presented in this wikibook are the views of their respective writers and do not necessarily reflect the views of our professor, Dr. Gifford, or that of our institution, George Mason University.

Summary[edit | edit source]

The Central Artery/ Tunnel Project, famously known as the “Big Dig”, is located in Boston, Massachusetts, in the United States. Originally proposed in the 1970s, the project was supposed to improve traffic flow and congestion and to create large green spaces in Boston. The project included moving the 6-lane elevated I-93 interstate highway, also called the central artery, underground by constructing an underground expressway tunnel, extending the I-90 interstate through South Boston, across the Boston Harbor, to Logan International Airport, and building the Leonard P. Zakim Bunker Hill Bridge over the Charles River for I-93. The I-93 tunnel is now called the Thomas P. O’neill Jr. Tunnel and the underwater tunnel extending I-90 to Logan International Airport is now called the Ted Williams Tunnel. The project was awarded to Bechtel Corporation and Parsons Brinckerhoff Joint Venture by the Massachusetts Highway Department to manage the massive project. The ground was broken in 1982 and construction was meant to be completed in 1998 and was estimated to cost around 2.8 billion dollars. The Big Dig pushed the boundaries of innovation and engineering and set foot to take on massive feats that had never been done before. The project, however, ran into many problems and was surrounded by controversy and local pushback. Many parts of the original design proved to be insufficient and had to be redesigned. All the changes led to massive delays and an enormous budget overrun. The project was finally complete in 2007 and ended up costing an astonishing $14.6 billion but with interest owed, it will end up costing a total of $22 billion dollars to be paid by 2038.

Annotated List of Key Actors and Institutions[edit | edit source]

The Big Dig Project was an enormous task and had countless people and organizations that had a stake in it. Due to the massive size of the project, the design and construction was broken into dozens of smaller sub projects awarded to subcontractors. Some of the major stakeholders in the central Artery/ Tunnel Project include:

Private Sector Actors and Institutions[edit | edit source]

Bechtel Corporation and Parsons Brinckerhoff Joint Venture

Joint venture of Bechtel Corporation and Parsons Brinckerhoff, now WPS USA, were hired by the Massachusetts Highway Department in 1985 to manage the design, construction, cost estimates and budget forecasts of the project. [6]

Bechtel Corporation: is an American engineering, procurement, construction, and project management company founded in 1898 and is headquartered in Reston, VA. [7]

Parsons Brinckerhoff: now known as WPS USA, is an engineering and design firm founded in 1885 based in New York, NY. [8]

Frederick P. Salvucci, was the state’s Secretary of Transportation. He advocated for the Big Dig and the need for it to be built for many years. He is considered the “Man behind the Big Dig” and the project wouldn’t have happened if it wasn't for his efforts. [10]

Robert Albee, was the state’s Director of Construction Services. To oversee the design and engineering for the Central Artery Tunnel Project, he left his job as Massachusetts chief engineer in 1985 to take this new position and stayed the director till 1998. [9]

Public Sector Actors and Institutions[edit | edit source]

Massachusetts Highway Department (MDH): Was the owner of the Big Dig Project from inception to 1997. MHD was responsible to oversee the project in its entirety. [14]

Massachusetts Turnpike Authority (MassPike): MassPike took over the project from MDH in 1997 and assumed all responsibility for maintaining it into the future. It is the current owner and Operator of the Central Artery/ Tunnel Project. It maintains and repairs the project and is responsible for its operating expenses and repair budgets. [11]

Federal Highway Administration (FHWA): FHWA was the primary funding agency for the Big Dig and was responsible for oversight of the project budget and finance plan. [14]

Massachusetts General Court: At the beginning of the project the General Court was responsible for the required funding remaining after what the funding provided by the FHWA. [11]

The Original Plan[edit | edit source]

Boston’s Big Dig project (also known as the Central Artery/Tunnel Project) began with a series of highway-expansion plans to solve the city’s increasing traffic and economic problems. The city of Boston is a history rich city with a road system that was designed before the automobile. The city contained a highway system opened in 1950 which featured a six-lane two-way highway linking southeast with the north and offered many offramps to access the city. This existing expressway drove right into the middle of downtown Boston with a series of high, above ground ramps in the middle of the city. This expressway was designed to contain 74,000 cars per day but was containing upwards of 200,000 cars per day which led to nightmare traffic congestion.

The project was divided into two major components: moving the 6-lane elevated I-93 highway underground into a state-of-the-art underground expressway (named Thomas P. O’neill Jr. Tunnel) and extending I-90 through an underwater tunnel (named Ted Williams Tunnel) from South Boston to Logan International Airport. Other projects were also completed as part of the Big Dig including the construction of the Leonard P. Zakim Bunker Hill Memorial Bridge over the Charles River and the Rose Kennedy Greenway which is open spaced green parks to replace the old above-ground I-93 expressway. There were also other smaller projects with general improvements to the existing infrastructure in Boston.

In March 1982, Boston was awarded $2 billion in federal funding. The original cost estimate, made in 1985, was $2 billion (costs later soared to $14 billion). The plan was significant since it would be the most extensive urban highway project in the United States since President Eisenhower’s interstate highway program.

The original cost estimate was 2.8 billion to start construction in 1982 and finishing in 1998. However, the project wouldn’t be complete until 2007 with a cost of 14.6 billion but with interest being paid the total cost is 22 billion and won’t be paid until 2038. The Boston Globe reported that a billion dollars of the project’s budget was lost due to design flaws.

Why Do the Big Dig?[edit | edit source]

Because of the city’s congestion, more automobiles were on the road than the roads were designed to handle, resulting in deadly delays and slow travel. All traffic east, west, north, and south used the central artery.  The Central Artery was designed to have 74,000 cars however by the 1990s it had upwards of 190,000 cars per day. This led to a 500-million-dollar loss to traffic jams. Traffic was stuck in the Central Artery upwards of 14 hours per day. Over 5,000 workers were involved in the Big Dig. In building the Big Dig, there was a 62% decrease in vehicle hours of travel on I-90 from 38,000 hours per day to 14,800 hours. Additionally, Carbon monoxide levels have reduced by 12% since its completion in 2007 since cars are not stuck in traffic. With the Big Dig, the greenbelt of 27 acres parks and open space where the old expressway stood was opened up which drastically changed the scene of the city and improved businesses. The tunnel allowed the city of Boston to reunite with the north neighborhoods that were previously separated by the above ground highway system. This separation caused economic harm to the businesses present there. Today, the Shawmut Peninsula is one of the most sought after urban real estate locations in the country.

The project’s original purpose was to improve traffic flow in the central artery and to create large green spaces to decrease pollution. Furthermore, the project’s objectives were to increase local and regional economic activity, improve pedestrian and cycling safety, open up new and under-utilized sections of the region for development, and improve the general quality of life for inhabitants in the surrounding districts (Greiman & Sclar, 2019).

Map[edit | edit source]

Design[edit | edit source]

The Big Dig or the Central Artery/ Tunnel Project is commonly considered as a single project, however, the project included three major individual construction projects in the center of the city of Boston. The Big Dig encompassed countless small projects and tasks, however the three major undertakings included:

Depressing the Central Artery

The original I-93, also known as the central artery, was a 6-lane elevated highway that went through downtown Boston. This highway was depressed underground by constructing the Thomas P O’Neill Tunnel.The tunnel is 1.5 miles long and accommodates 4 lanes of traffic. Before construction could begin, utility relocations and mitigation efforts had to be performed.[12] To allow daily life to continue as is, slurry walls had to be constructed so that the existing elevated artery could still be functioning while the excavation for the tunnel took place. The Big Dig represents the largest use of the slurry wall technique in North America. The slurry walls were eventually incorporated into the permanent structure of the tunnel. Once the construction of the tunnel was complete, the elevated highway was demolished, with many new parks and green spaces built in its place. [14]

Extending I-90 through South Boston, across the Boston Harbor, to Logan International Airport

This endeavor consisted of constructing the Ted Williams Tunnel and the Fort Point Channel Tunnel. The Ted Williams Tunnel connects South Boston to Logan Airport. To build this tunnel, 12 binocular-shaped steel tunnel sections were built in the Bethlehem Shipyard in Maryland. They were each longer than a football field and were delivered using barges or floating vessels. Each section cost $1.5 million dollars. Once they were at the Black Falcon Pier, the sections were equipped with steel-reinforced concrete walls and roadbed. The harbor was drained and then a 0.75 mile trench was dug out. The tubes were then lowered into the trench and connected.[12] At the Fort Point Channel, the tubes could not be barged in due to existing bridges over the channel. This led the engineers to instead build a concrete immersed tube tunnel on-site. A casting basin was constructed using steel cofferdams to be able to cast the tunnel boxes. Once the tunnel boxes were dry, the basin was flooded by removing the cofferdams.[13] This allowed the tunnels to be floated out to be lowered into the trench that was dug out in the channel. The process was repeated to construct and transfer the remaining two tunnel boxes. All the tubes were then connected to form the tunnel under Fort Point Channel.

Building the Leonard P. Zakim Bunker Hill Bridge over the Charles River

Leonard P. Zakim Bunker Bridge is the world's widest cable-stayed bridge. [12] The bridge is named after an American colonist and a civil rights activist. It is located in Boston, MA and was built in 2003 at a cost of $100 million [20]. The bridge is owned by Massachusetts Turnpike Authority, designed by Christian Menn, a Swiss engineer, and constructed by Bechtel/Parsons Brinkerhoff. [21] This bridge is 1432 ft long and has 10 lanes. [12] Eight of these lanes pass through the legs of the twin towers, and the other two lanes are cantilevered on the east side. It was built as part of the Big Dig project and replaces the existing deteriorated bridge that crossed the Charles River. The bridge has an average deck width of 183 ft and a structure length of 1407 ft. [20] Additionally, it has the following span length (ft): 112/130/745/250/170 [20] Leonard P. Zakim Bunker Bridge is connected to the Thomas P. O'Neill, Jr. Tunnel on one side of the river, and to Route 1 and I-93 on the other side of the river. Furthermore, this bridge holds the distinction of being the “first hybrid cable-stayed bridge in the United States” [12], as the frame of the bridge is made up of steel and concrete.

Timeline[edit | edit source]

Year Event
1982 - Work begins on Final Environmental Impact Statement/Report (FEIS/R)
1985 - Final Environmental Impact Statement/Report (FEIS/R) filed; approved early the next year
1986 - Bechtel/Parsons Brinckerhoff begins work as management consultant
1987 - Congress approves funding and scope of project
1988 - Final design process under way
1989 - Preliminary/final design and environmental review continue.
1990 - Congress allocates $755 million to project
1991 - Federal Highway Administration issues Record of Decision, the construction go-ahead

- Final Supplemental Environmental Impact Statement/Report (FSEIS/R) approved

- Construction contracts advertised and awarded

- Construction begins on Ted Williams Tunnel and South Boston Haul Road

1992 - More than $1 billion in design and construction contracts underway

- Dredging and blasting for the Ted Williams Tunnel are ongoing

- Downtown utility relocation to clear path for Central Artery Tunnel construction begins

- Archaeologists find 17th and 18th-century artifacts at a North End dig

1993 - South Boston Haul Road opens

- All 12 tube sections for Ted William Tunnel placed and connected on harbor floor

1994 - Charled River Crossing revised design and related FSEIS/R approved
1995 - Ted Williams Tunnel opens to commercial traffic
1996 - Downtown slurry work under way for I-93 tunnels
1997 - Utility work 80% completed
1998 - Enter peak construction years

- Construction begins on the Charles River Crossing

1999 - Construction 50% complete
2000 - Close to 5,000 workers employed on the Big Dig
2001 - Construction 70% complete
2002 - Leonard P. Zakim Bunker Hill Bridge completed
2003 - I-93 Northbound opens in March

- I-93 Southbound opens in December

2004 - Dismantling of the elevated Central Artery (I-93)
2005 - Full opening of I-93 South
2006 - Reached majority completion of the Central Artery/Tunnel project in January
2007 - Construction on development parcels continues after Central Artery/Tunnel Project completes

Risk[edit | edit source]

The implementation of adequate project management plans, techniques, and practices is vital for the overall success of the project. The construction of the megaprojects comes with inherent risks and Big Dig being one of the most technically challenging projects in the United States had several risks associated with it. The complexity of the project is evident from the fact that it includes, “the deepest underwater connection, the largest slurry-wall application in North America, unprecedented ground freezing, extensive deep-soil mixing programs to stabilize Boston’s soils, the world’s widest cable-stayed bridge, and the largest tunnel-ventilation system in the world” [3]. Extensive risk assessments and environmental feasibility studies were therefore conducted before the commencement of the project.

Several programs and innovative tools were used to mitigate the overall risk associated with the Central Artery/Tunnel Project. The Safety and Health Awards for Recognized Excellence (SHARE) program integrated risk management practices to reduce and prevent the occurrence of accidents. Additionally, the Community and Business Artery Public Awareness Program had several meetings to address project-related issues [4]. The owner-controlled insurance program (OCIP) was also implemented, which provided coverage for contractors and designers [4]. In addition to the OCIP, an integrated audit program was adopted which identified and mitigated project delays [3]. The project still faced several issues regardless of implementing all of the risk management practices. These issues contributed to the significant increase in the overall cost of the project.

There were tremendous risks associated with the construction of the Big Dig and some of these risks were difficult to identify in a timely manner. These unanticipated risks detrimentally impacted the cost, schedule, and scope of the project. Additionally, the last drawing package was provided to the bidders only five days before the contract was awarded and consisted of plans and drawings which were considerably incomplete [2]. As a result, it became impossible to quantify potential risks during the planning stage of the project and to accurately determine the cost and the schedule.

The Big Dig Project did not achieve project deliverables and goals in a timely manner because the initial “project management plan was based on flawed engineering specifications” [1]. This is evident by the fact, that only aerial photographs and “as-built” drawings were used for the preliminary site assessment instead of surveying the central artery. According to Anthony Lancellotti, an engineering manager at Bechtel, the company undertook a calculated risk by not surveying the site as the available drawing and photographs seemed sufficient for the project [2]. Contract documents show that this undertaken risk resulted in several change orders and claims [3].

The excavation of the site leads to the discovery of uncharted utilities, 150-year-old revolutionary-era sites, and weak soil. To prevent the utilities from getting damaged the Big Dig utility program relocated the utility lines [3]. The risk of damaging the utilities was still high because not all of the utilities were shown on “as-built” drawings. Additionally, a high risk was associated with damaging the infrastructure due to the building’s foundations being in close proximity to the construction site [3]. Any damage to the infrastructure had the potential of closing Boston’s major financial center and detrimentally impacting the region’s economy.

There were significant risks with respect to the construction and the installation of six concrete immersed tube tunnel sections under Fort Point Channel [5]. Virginia Greiman denotes that these sections were floated to their desired locations through the use of GPS [4]. Afterward, they were lowered below the surface of the channel and then supported by 110 steel reinforced caissons. These caissons and tubes were fitted together within 1/16 inch of perfection, therefore it meant there was no room for errors. There was also the risk of the tunnel section dislodging and collapsing on the existing subway, as these sections lie exactly 4 feet above the existing subway system. All of these risks were proactively managed by installing the tunnel section Line during the nonpeak hours and by doubling the insurance coverage. Furthermore, gates were installed to separate the subway line and the main train station, and barges with clay were also available nearby to quickly fill a potential leak in the tunnel wall [4].

Things Gone Wrong[edit | edit source]

The original design of the Charlestown Bridge proposed the use of 30 meters 100 ft highway ramps which was sued by the city of Cambridge for redesign. This forced the planners to come up with an alternative redesign. The redesign completed by Swiss engineer Christian Menn featured the cable-stayed bridge 436 meters and 1432 ft. in length, which is the widest cable-stayed bridge in the country.

The biggest obstacle that the project faced was that it had to be completed without a single disturbance to traffic flowing above the ground, which meant no homes, business, or subway systems would be demolished, rerouted, or stopped.  Local residents were not happy with the ongoing noise of the construction and protests to demand that a mandatory silence period be met. Local support for the project dimmed as time passed. This was compromised with a no construction period between 9PM to 5AM which affected the project’s deadline and caused a major delay for the completion.  

No digging

During the onset of the project, twelve I-90 connector steel sections were shipped out from Baltimore which needed to be matched exactly into the dugout trench in the tight-spaced and dark waters of the Boston Harbor. However, once they arrived the steel sections were three feet nine inches too short and did not completely fit in the floor of the harbor. The planners had to build a steel and concrete extension at the South Boston side to meet the short form steel box.  

Next, the central artery I-93 was to be tunneled underground however, the soft earth mixed with landfills was unstable to drill so planners decided to build a horizontal tunnel to minimize risk. In building the support system, a 37-meter 120 ft deep concrete wall using a slurry technique to support the underground tunnel was built. 2.9  million cubic meters of concrete was used for the wall. However, contractors did not remove gravel and debris before pouring the concrete which caused thousands of leaks later on. This also led to several lawsuits for providing substandard materials for the project which resulted in six employees being arrested and charged with defrauding the US in which a 50-million-dollar settlement was reached.

Additionally, lighting fixtures that were installed in the tunnel were faulty and fell which cost 50 million dollars to replace. Furthermore, “Ginsu Guardrails” were safety rails within the tunnels with squared off edges that allegedly caused eight deaths of ejected victims of crash accidents. These guardrails were removed by the state but only on the curved sections of the path.

During the digging, colonial artifacts were found which led to a pause in the digging to allow the artifacts to be recovered.  This led to significant delays in project deadlines. Environmentalists were concerned that the underground digging would disrupt the rat population underground, forcing them onto the surface.

Perhaps the worst of all was in 2006 when a 24-ton concrete paneling fell onto a passing car immediately killing the passenger and seriously injuring her driving husband. The concrete panel failing was due to the misuse of the epoxy glue which was not intended for long term use. In response, governor Mitt Romney ordered a full safety audit for the tunnel reopening all sections in June the following year.

Five years into the project, the tunnel had to be passed above the red line subway built in 1914 underneath the Fort Point Channel. The team excavated the existing channel until four feet remained to build 110 concrete foundations around the red line such that the tunnel was supported above it. The initial plan was to redirect the railway lines but that plan was quickly changed. In September of 2001, there was a massive leak in the tunnel section in Fort Point Channel causing 70,000 gallons of the Atlantic ocean in every minute. The most immediate threat was towards the tunnel section that was proximate to the red line subway which carried 218,000 commuters every day. The casting basin and tunnel were flooded to equalize the pressure from the leak and prevent the tunnel sections from becoming dislodged.

Political Issues[edit | edit source]

Acquiring Funding[edit | edit source]

Though many might argue that the Big Dig was an engineering solution that should not be politicized, the project was inevitably a highly political issue. Though the designing and logistics of the project were complex, getting enough political support to appropriate funds to the project added another layer of issues to the project.

The project was originally conceived in the 1970s, the brainchild of then Massachusetts Governor Michael Dukakis and Secretary of Transportation Frederick Salvucci, and both knew that Massachusetts would need federal funds to begin the project. The first attempt to gain financing for the project was in 1976, when then House Majority Leader Tip O’Neill inserted initial funding for the project into federal highway legislation. Despite this initial funding, the first ask for major federal funds to actually begin the project did not occur until more than decade later, in 1987. President Ronald Reagan greatly opposed the Big Dig, opposing it on financial grounds, stating that “...I remain firm in my pledge to the American taxpayers to speak out against such budgetary excesses…” [1] and went on to veto highway legislation that included funding for the Big Dig. Despite this, the Senate overrode his veto, and the Big Dig was financed for the first time.

This was not the end of funding issues, however, and the initial funding would not come close to covering all the costs the Big Dig would eventually incur.

Political Opposition[edit | edit source]

The Big Dig was unpopular amongst many outside the project, particularly after the project began and the true cost of the project began to balloon. In the late 1990s, after the estimated cost of the project reached the ten billion mark and “a whopping $1 billion a mile”[2] , opponents to Big Dig, primarily congressional Republicans, asked for a federal spending cap to be put in place.

A leading opponent of federal funding for the Big Dig was Virginia Representative Frank Wolf, who called on the US Department of Transportation to cap off federal Big Dig spending. He stated “...The cap would not be done in a way to hurt Massachusetts…” in 1996, a grave foreshadowing to the extensive debt the Commonwealth of Massachusetts would incur to complete the project.

In the end, federal opponents got their way. The US federal government would, around the turn of the millennium, no longer fund the Big Dig beyond what it had already provided in grants. Though the opposition never stopped the construction of the Big Dig - that was never their goal - the remaining responsibility was on Massachusetts and Boston entirely [3].

Financing and Funding the Project - Cost Overruns[edit | edit source]

The Big Dig was a completely publicly financed project, with a range of funding coming from state, federal and local sources in proportions that varied by year, administration and by the project’s outlook, and in amounts that ended up to never be enough. The project was intended to cost a mere six billion dollars when given final approval in 1990, 90% of that funding was to come from federal grants [1]. An initial 755 million dollars was approved that year to begin the project, though almost immediately the beginning of construction was delayed [2]. In fact, the project was already delayed since being originally proposed in the 80s, but the Reagan Administration delayed funding for the project. This resulted in the original cost estimate of six billion to already be inaccurate by 1990 [3] [4] The price tag only continued to inflate from there. From the original six billion dollar price tag, the total cost (including seven billion dollars in interest to be paid on debt eventually incurred by the Commonwealth of Massachusetts) totals to be 22 billion dollars, which is project to be paid off at last in 2038 [5]. The cost overrun came from several areas [6].

Technical issues[edit | edit source]

The Big Dig was extraordinarily complex, requiring new techniques such as freezing the earth to safely tunnel or using slurry to construct the tunnel walls, as well as issues resulting from the construction, such as archeological examinations whenever the project ran into pieces of Boston’s history. There was also the issue of acquiring land for the project, though much of the project was on government owned property, frequently the project would require “staging areas” for large sections of the project, such as creating a casting area to manufacture tunnel sections on site.

Mitigations[edit | edit source]

Despite the benefits the project would eventually bring, the Big Dig was unpopular or heavily critiqued. This would include residents complaining about noise from the 24 hour construction or environmentalists complaining about destroyed wetlands. To mitigate these issues, the project spent nearly three billion dollars relieving various complaints, accommodating locals, or even, as Michael Fein of Johnson and Wales University provides an example of: “When the project destroyed wetlands, project managers agreed to build a park elsewhere.”

Projects like these, or installing soundproof windows, or improving streetscape because of a resident’s needs, cost millions of dollars each. Though a million dollars from a fifteen billion dollar project is almost a rounding error, many small projects began to add up.

Political Issues and Public Project Philosophy[edit | edit source]

Frederick Salvucci, the visionary and de facto leader of the project, credits the delays and ballooning costs to a change in administration and political philosophy in 1991, when Bill Weld became Governor of Massachusetts. Salvucci notes that, after the change in leadership, reconsiderations of the project’s scope and design, privatization of key actors in the project and what Salvucci described as a “...[lack] of capacity to make informed judgements”, led to delays, internal conflicts, and further impact studies that themselves delayed the project and added further costs.

Furthermore, Salvucci notes that once cost issues began to arise, the Weld administration resorted to “creative financing”, and, Salvucci claims, “[t]here was no honest disclosure of problems at the earliest possible moment to search for solutions, problems were hidden for as long as possible to the point in time that no options were available” [7]. These delays, build up of problems, lack of project efficiency and organization due to restructuring and lack of transparency further added to the inflated cost, though an exact dollar estimate is unknown.

Another issue had to do with a change in philosophy of the process of the project. Whereas in the 1960s when the Central Artery was originally constructed, public officials and highway designers had no qualms with tearing down residences and dislocating 20,000 locals for the benefit of the project. This cheap, goal-driven process was not shared by those who sought to replace the Central Artery. They saw the philosophy of the original project as Machiavellian and sought to approach the replacement much more as a “friendly neighbor”. This meant: not disturbing traffic, not destroying private property that would otherwise make the project easier if it was removed, and maintaining the day to day routines of the city. The challenge was made: build a highway as you drive on it.

Redesigns[edit | edit source]

One final issue that led to the cost overruns was the constant redesigns that plagued the project from the start. Rather than settling on one design and committing to it, various actors involved in the project pressured, proposed or demanded minor to significant redesigns of various aspects of the project. One such example was the Federal Highway Administration threatening to cut off federal funds until the central artery was widened for future road demand. Some redesigns were political in nature, others were pragmatic, more were small and resulted from technical challenges, safety necessities or succumbing to resident demand. All in all, redesigns cost an additional three billion dollars.

Debt[edit | edit source]

On the issue of debt, Massachusetts has dug themselves quite a big hole, if you’ll excuse the pun. Particularly in the early years after the completion of the Big Dig, Massachusetts found itself into a precarious financial situation. With 22 billion in debt, the state was forced to take away funding from other projects to service bonds floated for the project. This led to a “kicking the can” situation, where other capital improvements are in desperate need of attention, and initiating those projects will require more debt to be floated. This led the Commonwealth of Massachusetts to be in a rather precarious situation, as they found themselves (in 2008) to have the highest debt per capita of any state, and it spends 38% of its highway budget on debt services, compared to a national median of 6% [8] . The issues are troubling, however it does not appear as though the Commonwealth has capitulated under this debt.

Local Concerns and Mitigation[edit | edit source]

Despite the benefits to the environment, to traffic and to the urban fabric of Boston that the Big Dig promised, the project faced layers of opposition. Local residents complained about the noise and other disturbances caused by constant construction, day and night, for years on end. Environmentalists complained about various impacts construction would have on the environment. Businesses in Boston feared that construction or any delays to the highway the Big Dig was replacing would disrupt commercial traffic in the city.

These various groups had, through various mediums, the power to disrupt, delay or terminate the Big Dig as a project, despite the project having already begun. The actors behind the project could not allow this to happen, and with no easy solution to solve every groups complaints, the project had to resort to mitigations and promises. For locals, the Big Dig funded soundproofed windows and even new mattresses that absorbed vibrations from construction. For the environmentalists: green space on top of the highway tunnel, and using excavated soil to make a new harbor park in Boston. For businesses: early on the promise was made that the central artery would not be closed, ever, while construction was ongoing.

These various mitigations may seem preposterous and even crony, yet they worked. Despite the headaches caused by the construction of the project, political opposition and the occasional local adamantly opposing the project, “more than 80 percent of Boston residents and nearly two-thirds of state residents supported the Big Dig” [9], leading to continued support. One striking example of mitigation was nearly one billion dollars spent to rework the planned bridge that was opposed by residents, business owners and the City of Cambridge. Despite the fact that the bridge (likely) was perfectly fine, the project had to maintain popular support, and as a result the bridge was redesigned at great cost.

These various mitigations added up. In addition to the one billion spent on bridge reworking, the overall costs of mitigation added up to be a third of the Big Dig’s overall price tag, roughly five billion dollars.

One striking example of mitigation was nearly one billion dollars spent to rework the planned bridge that was opposed by residents, business owners and the City of Cambridge. Despite the fact that the bridge (likely) was perfectly fine, the project had to maintain popular support, and as a result the bridge was redesigned at great cost. These various mitigations added up. In addition to the one billion spent on bridge reworking, the overall costs of mitigation added up to be a third of the Big Dig’s overall price tag, roughly five billion dollars.

Effects of the Big Dig[edit | edit source]

The Big Dig met (and in some cases exceeded) its goals. Traffic flow was improved 62%, while saving nearly $170 million a year in reduced vehicle operating costs and reduced time spent in traffic. There has also been a marked improvement in air quality, with a 12% reduction in air pollution. This couples with the increased green space, with more than 315 acres of new park space open to the public where the Central Artery once ran.

The Big Dig has also seen improved investment in downtown Boston, particularly in the Back Bay and South Boston Seaport areas that were once cut off by the elevated Central Artery. Over $7 billion in urban investment has been committed to these areas, including 7,700 housing units, millions of square feet of commercial space and an estimated 43,000, compared to the construction of the Central Artery which displaced 20,000 residents during construction. The full benefits to the city are yet to be realized and will continue to unfold as long as the Big Dig is utilized and Boston exists as a city [10].

Discussion Questions[edit | edit source]

  • Was the Big Dig worth its cost?
  • Would Boston have been better off pursuing some other alternative?
  • What alternatives could have been proposed?
  • What should the Big Dig have done differently?

Additional Readings[edit | edit source]

From YouTube:

This is a short documentary, primarily on the construction of the project. It does not go into detail about certain issues, but it provides a comprehensive overview of the project.

References[edit | edit source]

1) “Project Manager's Handbook.” Edited by David I Cleland and Lewis R Ireland, McGraw Hill, 2008,'s%20Project%20Manager's%20Handbook.pdf#page=254.

2) Lewis , Raphael, and Sean Murph. “Artery Errors Cost More than $1b.”, The Boston Globe, 2003,

3) Greiman, Virginia. “The Big Dig .” NASA, 2020,

4) Greiman, Virginia A. Megaproject Management: Lessons On Risk and Project Management from the Big Dig. Wiley, 2013.

5) Commonwealth of Massachusetts. “The Big Dig: Facts and Figures.”,