Obayashi Corporation
The project was managed by the Massachusetts Turnpike Authority, with the Big Dig and the Turnpike's Boston Extension from the 1960s being financially and legally joined by the legislature as the Metropolitan Highway System. Design and construction was supervised by a joint venture of Bechtel Corporation and Parsons Brinckerhoff. Because of the enormous size of the project—too large for any company to undertake alone—the design and construction of the Big Dig was broken up into dozens of smaller subprojects with well-defined interfaces between contractors. Major heavy-construction contractors on the project included Jay Cashman, Modern Continental, Obayashi Corporation, Perini Corporation, Peter Kiewit Sons' Incorporated, J. F. White, and the Slattery division of Skanska USA. (Of those, Modern Continental was awarded the greatest gross value of contracts, joint ventures included.)