The most expensive highway project in U.S. history best known for its unofficial nickname, Big Dig, was a true mega project. The officially named Central Artery/Tunnel Project (CA/T) cost an estimated 14.6 billion dollars, and took an additional 9 years past the originally scheduled date for completion. In essence, the Boston project rerouted the city’s Interstate 93, its central artery, into a 3.5 mile long tunnel.
Although the concept behind the project was a sound one, and some version of the project had been recommended since the 1930s, the actual completion of the Big Dig was hounded by escalating construction costs and a lot of bad circumstances, including deaths, leaks, and design flaws. At the end of the project, the partnership between the program manager and the Massachusetts Turnpike Authority came to an abrupt end, and many companies part of the construction had to pay millions of dollars in restitution.