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Boston University Assistant Professor Virginia Greiman discusses enduring lessons from the largest, most technically challenging highway project in U.S. history.

Boston’s Central Artery/Tunnel Project, known internationally as the Big Dig, is renowned for its massive problems and cost overruns as well as being an engineering marvel. Larger than the Panama Canal, the Hoover Dam, and the Alaska Pipeline projects, it was built through the heart of one of the nation’s oldest cities and included numerous engineering firsts.

In this episode of Small Steps, Giant Leaps, you’ll learn about:

  • Major lessons learned from the Big Dig and how they apply to other projects
  • Design and implementation challenges on the Big Dig
  • Measures that could have been taken to contain cost


Related Resources

The Big Dig: Learning from a Mega Project

Tunnel of Terror: “The Big Dig” Ceiling Tile Collapse

System Failure Case Studies: Tunnel of Terror

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APPEL Courses:

Leading Complex Projects (APPEL-vLCP)

Pay It Forward: Capturing, Sharing and Learning NASA Lessons (APPEL-vPIF)

Cost Estimation for Project Managers (APPEL-vCOST)

Assessing Project Performance (APPEL-vAPP)


Virginia Greiman Credit: Virginia Greiman

Virginia Greiman
Credit: Virginia Greiman

Virginia Greiman is an Assistant Professor, Administrative Sciences at Boston University. Greiman, a certified Project Management Professional, served as Deputy Chief Legal Counsel and Risk Manager on Boston’s “Big Dig” project. She is an internationally recognized expert on mega-project management and infrastructure development, privatization and project finance, corporate reorganizations, cyber-trafficking, and international commercial transactions. Greiman has held several high-level appointments for the U.S. government, including as United States Trustee for the U.S. Department of Justice, and international legal counsel to the U.S. Department of State and the U.S. Agency for International Development on privatization projects in Eastern and Central Europe. She recently advised on mega projects in India, Africa and Southeast Asia as well as Europe’s largest mega project, London’s Crossrail project. Greiman has a bachelor’s from Pennsylvania State University, Master of Education from Boston University, Juris Doctor from Suffolk University and Master of Laws in Taxation from Boston University School of Law.




Virginia (Ginny) Greiman: Learning and knowledge sharing is to me, without question, one of the most important things we can do on a project so that future projects can better meet the challenges they will face.

Integration remains a major concern on all projects. The more we integrate, the better we collaborate. The more we collaborate, the more we can innovate.

Deana Nunley (Host): Welcome to Small Steps, Giant Leaps, a NASA APPEL Knowledge Services podcast where we tap into project experiences to share best practices, lessons learned and novel ideas.

I’m Deana Nunley.

The Big Dig, officially called the Central Artery/Tunnel Project, was the largest, most challenging highway project in U.S. history. An article entitled, ‘The Big Dig: Learning from a Mega Project,’ has been one of the most popular articles on the APPEL Knowledge Services website since it was published more than a decade ago.

The author, Virginia Greiman, is an assistant professor at Boston University and former Deputy General Counsel and Risk Manager of Boston’s Central Artery/Tunnel Project, and she joins us now to discuss enduring lessons from the Big Dig.

Ginny, thank you for being our guest on the podcast.

Ginny: My pleasure. I’m delighted to be here.

Host: For anyone who may not be familiar with it, could you give us a quick refresher on the Big Dig?

Ginny: Yes, I’d be happy to. The Big Dig was the largest project to date in U.S. history at 14.8 billion, and also the largest inner-city project in the world. It was built to replace an inner-city viaduct that was constructed in the 1950s and was about to collapse because the increase in vehicles. It was built for 75,000 vehicles, and by the 1980s was close to carrying 200,000 vehicles. It’s been described as one of America’s greatest engineering feats. However, it’s also been criticized as a prime example of costly public projects that were over budget and behind schedule.

I think the most important aspects of the Big Dig are the number of firsts in terms of its technology. It was the first extensive use of slurry wall construction. It was the first and the widest and deepest circular cofferdam in North America, where we actually built our tunnel boxes. It was the deepest land/water connection, 90 feet below the surface of Boston Harbor. We connected the land-based tunnel with the water-based tunnel.

We had one of the largest highway tunnel ventilation systems in the world and the widest cable-stayed bridge in the world known as the Leonard P. Zakim Bunker Hill Bridge. We also used an extensive amount of concrete for the immersed tube tunnels, and it was the largest ever used in the United States. It was the first use of jacked vehicle tunnels, and it was the first major inner-city project to establish 300 acres of open parks and space. These are just some of the initiatives. There are many more but there was no question, this was a one-of-a-kind engineering undertaking, certainly for the United States.

Host: What was your role in the Big Dig?

Ginny: Well, I served a dual role. I served as Deputy Chief Counsel and Risk Manager on the project’s 12-member executive team. We were involved in developing strategies and policies that would be beneficial to all project stake stakeholders. This involved working closely with our management consultant and engineers, our construction teams, our local community representatives, and our many government agencies that were involved in the project.

My role was to not just identify, assess and mitigate the risks of which there were many, but even more important was to develop opportunities such as implementing the first-of-its-kind and largest owner-controlled insurance program, developing initiatives to improve and prevent serious losses, implementing the first-of-its-kind safety incentive program, where the workers were actually rewarded monetarily for good performance and reduced accidents and lost time.

But I think probably the most important thing that I had to do was communicate with the many stakeholders, including the environmental organizations, community groups, and all those who wanted to learn more about the project and were interested in becoming involved. So sharing knowledge was a key aspect of my role. And to this day, I feel it’s important to continue to share that knowledge that was gained on this project.

Host: What prompted you to expend considerable time and energy to capture and share the lessons learned from the Big Dig?

Ginny: Well, it actually happened at the end of the project when as all projects do pack up their boxes and recognize for the first time that these boxes are going into storage, and they may never be opened again. And this encouraged me to want to share these great lessons learned with other projects, with policy makers, with engineers, with contractors, so that their life might be easier for future mega projects. Learning and knowledge sharing is to me, without question, one of the most important things we can do on a project so that future projects can better meet the challenges they will face. So I started a learning center for mega projects at Boston University, where my students who come from around the world could study the lessons, not just from the Big Dig, but also other major projects. I also wanted to write about the project, to describe some of our problems and how we resolved them, and just generally to share the knowledge of what it means to undertake a massive project, a massive mega project.

Host: More than 15 years since completion, why do you think people are still so fascinated with this project?

Ginny: Well, it’s a great question. And it’s something I do think a lot about. I think it has a lot to do with the fact that this project transformed a city from a concrete city to green space. And I think anytime you transform a city and open up a city to parks and green spaces, it is absolutely fascinating to people, particularly those that knew what it looked like before, that understood the serious traffic congestion we had in Boston. Sometimes it took two hours to get through the city. Now we can get through in 10 to 12 minutes.

That’s a massive difference. I think people also like large transformative projects that improve their quality of life and add to the aesthetics and conservation of a city. For example, Seattle Alaskan Way project is very similar to the Big Dig in that it improved public safety, provided efficient movement of people and goods. It bolstered the local, regional, and state economies. And certainly in Boston, it has enhanced our green space. We created more than 300 acres of new parks and open spaces. We connected neighborhoods. So those that live in the North End now can be connected with other parts of the city where before they were obstructed by this huge concrete viaduct. I also think our city was separated from its waterfront by this ugly highway known as the Green Monster. And I think opening up the waterfront and allowing people to recognize what a beautiful city Boston was that really had been hidden from them in the past. But your question really is very important because there is no question that we are intrigued by these large undertakings.

Host: With the Big Dig project, what caused the cost escalation and what could have been handled differently to contain cost?

Ginny: That is a question I receive all the time as do all mega projects. And we are still studying the Big Dig along with other projects to determine why these projects continue to be over budget and behind schedule. For example, the Crossrail project in London is just nearing completion. They’ve opened the Elizabeth Line, and similar to the Big Dig, interestingly, they were about three years late and four billion over budget. Now certainly no one plans for that. But if I were to describe in one word what causes cost escalation, the word I would use is complexity. Complexity caused by multiple employers, complexity caused by multiple stakeholders, government agencies, and the interdependencies of all of the project activities, which impacted both cost and schedule. A lot of the literature talks about upfront planning. They call it the critical period and how important it is to plan before you begin design and construction.

And I agree with that, but at some point, we have to put a period in the planning because a lot of the complexity is caused by uncertainty that won’t become visible until we begin our project. For example, building in an inner city on the Colonial Shoreline, dating back to the Revolutionary War, we had many discoveries as the project evolved. There were many artifacts that were uncovered. There were many utility lines that we were unaware of. There were many sewer pipes that we had no knowledge of. So at some point projects have to say, ‘We just have to begin.’

It’s during the time of implementation, during construction, that we begin to discover things that we were unaware of when we were planning the project. And I always like to say that the contractors very much recognize that projects are more complicated than they had originally thought. In other words, you could spend 20 years planning, but you wouldn’t uncover the complexity and the uncertainty until you actually began the project. That’s what makes it very difficult to determine your budget in advance.

Host: On the Big Dig, what were the biggest design and construction challenges?

Ginny: Well, there were many. We had a lot of surprises. We had unchartered utilities we were unaware of, subsurface conditions that we had no knowledge of, many dating back to the Revolutionary War. We had ground water conditions. We’re a city built on water like Amsterdam, which was one of the first cities in the world built on water. So we had weak soil condition. We had artifacts. We had hazardous materials to deal with. We had to, as the project evolved, continue our design. In other words, for any mega project, it’s very difficult to have design complete before you start a construction.

This is a process known as fast tracking where while you’re designing, you’re also constructing the project. As you’re doing this, you’re learning. You’re learning about technology. You’re recognizing that maybe some of the technology you had planned to use would no longer work for you. So anticipating what might be happening, it’s very, very difficult. We’re getting better in some respects at it, as we learn to share knowledge, but there will always be uncertainties and stakeholder expectations that may be very difficult to meet. But nonetheless, we always have to strive to do that.

Host: In the Big Dig article that you wrote for APPEL Knowledge Services in 2010, you outlined four major lessons learned from the Big Dig, and it would be great if you could share your thoughts on each of them. Let’s start with project integration is critical to success.

Ginny: Yes. And that is still true. And in fact, after finishing the Big Dig, in 2017 with the assistance of MIT Systems Engineering Program and the Project Management Institute, I participated in a study and the writing of a book involving the importance of integrating systems engineering and program management. We can look to any project and see how it is important that each of these roles be integrated so that the systems engineer understands the needs of the program manager and the program manager understands the needs of the systems engineer. That’s just one example of interdisciplinary integration. I continue to study it because it continues to be a major problem on the projects on which I consult. When we work in isolation, we’re really working at a level where we have a lot of uncertainty and a lack of knowledge. It is critical that the organization itself be integrated.

The Big Dig was integrated eventually, but not until about eight years into the project. That was too late. We should have integrated our teams from the public and the private sector much earlier on. One of the reasons for doing this is so that we understand what each other wants. Sometimes it’s not clear what your client wants. The private sector may find that there’s a lack of clarity. And sometimes the public sector does not understand what the private sector or the delivery team is capable of doing. So consequently integration remains a major concern on all projects. The more we integrate, the better we collaborate. The more we collaborate, the more we can innovate. So integration is connected with everything we do on a project, including finding ways to reduce cost, maintain schedule, improve quality, and share knowledge.

Host: What was learned through this project about goals and incentives?

Ginny: Well, goals and incentives are really important. Let me start with goals. Goals must be clear. When goals are not clear, the project can go off on a path that was not intended. Goals must be articulated. And if goals change, they must be communicated. Sometimes the goals of a project during the course of the project will change because there’s a discovery that what technologically you wanted to do initially you would not be able to do, or it will cost a lot more than you intended.

Incentives, on the other hand are important. I don’t believe that you gain much by penalties and punishment. I think we gain a lot more by incentivizing our designers, our construction workers, all of our stakeholders. But one thing I learned from the Big Dig is it is never a good idea to tie incentives to schedule or speed of completion. And I say that because speed is not a good criteria for developing successful projects. Yet, having said that many projects are incentivized by completing early. If you complete early and you haven’t delivered the benefits you’ve promised, then that incentive is basically a failure.

So, I think we need to think carefully about the incentives we use. One of the incentives we used on the Big Dig, which I thought was a terrific incentive and actually resulted in a reduction in accidents and lost time and violations was our safety share incentive program, which meant every six months, the workers would receive additional compensation, sometimes several thousand dollars for operating safely. That is an incentive that you can measure. And that produces outcomes that are positive overall for the project. So we have to think very carefully about the incentives we use, why we’re using them, and how we’re measuring them.

Host: Next up on this list of four major lessons learned: continuous improvement and rigorous oversight are both essential.

Ginny: Yes, we constantly are striving for doing things better. Not only technically, but improving our process and procedures. It’s very important as we did on the Big Dig to analyze weekly our lessons learned, take those lessons learned and turn them into better practices than we were using in the past, measuring step by step where we’ve gone wrong and how we can do things better to prevent risk in the future.

Rigorous oversight, yes, very essential. Rigorous oversight means you are holding people and organizations accountable for their mistakes, negligent actions or willful conduct. Nothing will change unless there is accountability. I’ve noticed on many projects; we often blame the engineers for project errors or damages when in fact it may be a leadership or a project management issue that caused the designer to pursue a path that was not in the project’s best interest. So this involves a very deep root cause analysis to determine what is causing our problems on a project. Oversight is critical. And I would also emphasize here that independent oversight, that means not just oversight from within the project, but also external oversight either through a group of experts or through an independent board or management group.

Host: The last of these four major lessons learned, addresses doing things as they have always been done. How did that factor into the Big Dig?

Ginny: Well, I like to use a quote from Albert Einstein who said that, ‘We cannot solve our problems with the same thinking we use to create them,’ because projects require new ways of thinking. If we continue to do things in the same way and we’re getting the same results and then we try to correct by doing things in the same way, we’re going to have the same problems. Another, a favorite quote of mine, which illustrates this point is from General Patton, who said, ‘If everyone is thinking alike, then somebody isn’t thinking.’ I think that’s so relevant to mega projects. We want diversity of thought. We want new ideas so we can generate better solutions.

Top-down decisions do not always produce the best result. That’s been proven again and again in case studies and in the literature. What I like to see on mega projects is the generation of more options to choose from just like when you’re selecting a new car or a new home, the more you look at the better decision-making that will take place. And I think that’s very relevant to mega projects. We must develop an ability of the people working on the project and create the environment where people can think creatively. That may mean taking risks, but it also creates opportunity that in the end will help to ensure greater project success.

Host: The National Transportation Safety Board determined the 2006 ceiling collapse in one of the Big Dig tunnels, which resulted in the tragic death of a car passenger, occurred because builders used the wrong epoxy to hold anchor bolts in place. From a safety perspective, what are the key lessons learned from that incident?

Ginny: This is a very important question. And I’ve learned a lot from the studies that have been done on this incident. I think one of the greatest lessons that I’ve learned is be careful of assuming knowledge. We all assume when we hire designers and contractors, that they’ve had experience in what they’re doing and that they will apply that experience to the project, and that safety certainly is a high priority. But the reality is when you are doing anything for the first time, all assumptions you are making must be tested and verified. And sometimes I think we get very comfortable. We assume knowledge that really isn’t there. And we allow the work to proceed without having carefully examined and analyzed the use of a particular technique that has not been used before. And this was certainly the case on the Big Dig.

We also need to watch for warning signs. In this particular incident, there had been a previous failure. Unfortunately, that failure was not reported to the people who need to know despite the fact that when incidents occur, what we call near misses, we require on projects that those near misses be reported. Even though no damage occurred, they might occur in the future. So what can we do to prevent these accidents from happening?

And finally, I would say sharing of knowledge, continuous monitoring of construction, not only during construction, but after completion. On the Big Dig testing was required to be done, and it was not always done in a timely fashion. But this is not unique to the Big Dig. I have found this on many other projects since then. In fact, I have found projects that don’t even implement a testing program until years after the project is complete. And then finally, management and engineering, that integration is so important. We need to understand decision making, particularly when time pressure is a factor. And that goes back to my previous point that we shouldn’t incentivize for speed. We should incentivize for quality, for innovation, for improvement, but when time pressure is a factor in decision making, we often see the wrong decisions made.

Host: Ginny, has anything new about this mega project come to light in the last 10 to 12 years?

Ginny: Well, yes. Let me take that question into some different directions. In the past 10 to 12 years, we continue to find ways to reduce cost. We recognize that projects cost a lot of money, but in order to reduce cost, we have to find better ways to reduce uncertainty. So, the more we eliminate uncertainty, the more we reduce complexity. The more we reduce complexity, the more likelihood that our costs will be reduced. So learning about what causes cost escalation and finding better ways to manage uncertainty is something I would say is progressing quite well at this point.

And since the Big Dig we’ve continued to learn about better management of uncertainty. We’ve also shared ingenuity and creativity with other projects and encouraged innovation. When we started the Big Dig, we had one of the first innovation programs — it was started by the Federal Highway Administration — ever developed on any project in the United States. Now we see other projects developing innovation programs. We also see projects looking at sustainability. I was very proud of how we managed environmental concerns on the Big Dig, but we also have to think about enhanced quality of life, making a city more livable, making it more sustainable. There were some things we could have done that we never got around to doing. And I think it’s important to understand when building a mega project, we should take advantage of as many opportunities as we can. In most projects you cannot accomplish everything you would like, but you at least should seriously consider things that you would like to have done in the future.

The other thing I would add is the importance. If the Big Dig were being built today, it would benefit from the new tunnel boring technology, which is currently deployed in the Swiss Alps for the 35-mile-long Gotthard Base Tunnel and the Alaska Way Viaduct replacement also used tunnel boring technology. Unfortunately, that did not work out so well for them, but it wasn’t because of the technology. It was because of a lack of understanding of underground subsurface conditions. I think today more and more mega projects are benefiting from the use of artificial intelligence, robotics, nanotechnology, machine learning, and all of these are helping to create greater efficiencies and also helping to reduce risk.

Host: What are your thoughts on how the Big Dig lessons apply beyond large infrastructure projects?

Ginny: That’s another great question. And I’d like to say that the lessons from mega projects apply to all projects, no matter how small or large, and the reason for that is they all relate to the development of relationship building, value creation, partnering, enhancing communication, developing positive attitudes about what can be done, managing risk and quality. So looking to mega projects for advice for smaller projects is something that every project should do and can learn from.

Host: You mentioned the concept of partnering. So that was a new concept on mega projects — still relatively new when it was implemented on the Big Dig in 1992. How did partnering benefit the project?

Ginny: Well, as expressed by our project director, partnering saved millions of dollars in the cost of litigation and arbitration. How do we know that? We had very little litigation. It also did something even more important. It helped us build those relationships between engineers and contractors that had to work together on a daily basis. If you had to spend time in litigation, spend time in court, it would not only be more costly, but it would also damage those important relationships. Projects involve and require a climate of collaboration and innovation, where we can explore new ideas in a more genial and a transparent matter without threats of retaliation or problems of conflict. So I can’t emphasize enough the importance of partnering. Building relationships is the key to success in large mega projects. And it’s essential that these communication channels be kept open throughout the life of the project.

Host: In the end is the Central Artery/Tunnel Project considered a success?

Ginny: Very important question, because we tend to spend a lot of time looking at cost and schedule. And a lot of our focus, not only on projects, but in the literature has been on cost overruns. If we were to put side-by-side the cost of a project with the benefits of the project, I can ensure almost every time we would find that the benefits far exceed the cost. Yes, the project delivered benefits that were not imagined when the Big Dig was first conceived. The benefits that are extremely valuable, but are rarely talked about include conservation, protection of wildlife, development of acres of green space, the building of an island, creating a home and a reef for shellfish populations, creating an environmentally friendly city, reducing travel time.

If we think of the time that we got back, that alone is a valuable asset and has been reported extensively in studies that have been done. Preparing your workforce for the future,  knitting neighborhoods. But one of the most important benefits I feel is creating knowledge and experience for future projects and looking at benefits holistically, not just the narrow view of benefits in terms of your immediate return on your investment, but the long-term benefits that may take 10, 20, 30 years before they are even realized.

Host: Ginny, it has been an absolute pleasure getting to talk with you. Thank you so much for sharing your knowledge and insights on the Big Dig.

Ginny: It’s my pleasure. Happy to share these lessons anytime.

Host: Do you have any closing thoughts?

Ginny: Yes. I do hope that people will be inspired by the successful projects of the past. The lessons learned, the risks that these great engineers and contractors have taken, even impacting their own lives. And I hope they will forge future projects and take these ideas from the past and apply them to their projects in the future so that they too may experience the great benefits that these projects continue to deliver for generations.

Host: You’ll find Ginny’s bio, links to topics we discussed during our conversation, and a transcript of today’s show at

We’d love to hear your suggestions for future guests or topics on the podcast. If you have a suggestion, please share your idea with us on Twitter at NASA APPEL – that’s app-el – and use the hashtag Small Steps, Giant Leaps.

As always, thanks for listening.