Case Study
The Big Dig’s Schedule, Analyzed
Boston’s Central Artery/Tunnel Project -- the “Big Dig” -- is one of the most publicly documented megaproject overruns in U.S. history, tracked in real time by the GAO and Massachusetts’ own Inspector General as it happened. The public record shows a nine-year schedule slip, reported update by update rather than discovered after the fact.
Every figure below is sourced to a specific public record, cited inline. This is historical analysis, not legal advice.
The Original Approval: 1985
When Congress approved federal funding for the Central Artery/Tunnel Project in 1985, the project was estimated at roughly $2.5 billion and targeted for completion by 1998.
Real-Time Oversight: GAO’s Contemporaneous Reports
Unlike many megaprojects where overruns only become visible in hindsight, the Big Dig was tracked as it happened by the U.S. General Accounting Office (GAO, renamed the Government Accountability Office in 2004), which issued a series of reports on the project’s cost and financing through the 1990s:
- A 1996 GAO report found the project’s total cost estimate had risen to $7.8 billion (not adjusted for inflation), and warned total costs could exceed $11 billion.
- That same report flagged that federal and state funding then in place might not be sufficient to complete the project by its 2004 target, and noted federal sources had provided $4.1 billion of the $4.7 billion obligated to date.
- A follow-up 1997 GAO report continued to track the project’s escalating costs and Massachusetts’s increasing reliance on state funding as future federal support grew less certain.
In parallel, the Massachusetts Office of the Inspector General issued its own series of reports from 1993 through 1999, identifying compliance problems with state regulations, unclear contract specifications, and what it described as a continuing failure to apply rigorous cost containment on project contracts -- including specific findings about a design consultant’s performance and contract compliance.
The Schedule, End to End
| Year | Event | Detail |
|---|---|---|
| 1985 | Federal approval | ~$2.5B estimate, targeted for 1998 completion |
| 1996 | GAO cost report | Estimate revised to $7.8B, could exceed $11B |
| 1997 | GAO financing report | Continued cost and funding-source scrutiny |
| 1998 | Original completion target | The date approved in 1985 comes and goes |
| 2004 | Revised target (per federal review) | A later projected completion date |
| 2007 | Actual completion | December 2007 -- roughly $14.8B total cost |
The project’s 1998 target date passed with construction still well underway. A later federal review process associated with the project’s final phases pointed to 2004 as a revised completion target -- which also passed before the project was actually finished. The Central Artery/Tunnel Project was completed in December 2007, widely reported at the time -- including by NBC News -- at a total cost of approximately $14.8 billion, against the roughly $2.5 billion estimate Congress had approved in 1985.
What the Pattern Shows
The Big Dig’s overruns didn’t emerge from a single missed milestone -- they compounded across more than two decades of tracked estimates, each new report showing a larger cost and a target date the project had already missed by the time the next report was published. That’s the same structural pattern a schedule health check is meant to catch early -- not by predicting the future, but by making a schedule’s own current trajectory visible before it compounds across another decade of updates.
Claims Digger tracks a project’s schedule history across every update you upload -- so a pattern like the Big Dig’s repeated target revisions shows up as a visible trend in the data you already have, not something that has to be reconstructed years later from a stack of old oversight reports. See how it works.
Sources
- U.S. General Accounting Office, “Central Artery/Tunnel Project” (RCED-95-213R, 1995)
- U.S. General Accounting Office, “Central Artery/Tunnel Project” (RCED-96-65R, 1996)
- U.S. General Accounting Office, “Central Artery/Tunnel Project: Cost and Financing” (T-RCED-96-218, 1996)
- U.S. General Accounting Office, “Transportation Infrastructure: Progress On and Challenges to Central Artery/Tunnel Project’s Costs and Financing” (RCED-97-170, 1997)
- Massachusetts Office of the Inspector General, reports on the Central Artery/Tunnel Project (1993–1999)
- Contemporaneous news reporting at project completion, December 2007
Part of Claims Digger’s public-record case studies. Related reading: The complete DCMA 14-point assessment · All case studies