Boston's Big Dig cost overruns and ceiling collapse (1991–2007)
Boston's Central Artery/Tunnel Project, known as the Big Dig, was approved at $2.8 billion and finished at $14.6 billion—a roughly fivefold increase. In 2006, a 26-ton concrete ceiling panel fell on a car in a connector tunnel, killing motorist Milena Del Valle. Investigators found the wrong type of epoxy had been used to anchor the panels.
Contractors paid more than $450 million in settlements. The Del Valle family received $28 million. Multiple state officials were fired over cost concealment.
The Big Dig became the standard reference point for American infrastructure mismanagement and reshaped how states approach megaproject oversight, procurement transparency, and contractor liability.
Like Miami's Signature Bridge, the Big Dig involved design and material failures discovered after commitments were locked in, cost increases that dwarfed the settlements extracted from responsible parties, and safety consequences that escalated public scrutiny. Both illustrate the gap between the damages caused by engineering errors and the professional liability coverage available to recover them.