Boston's Big Dig (1991–2007)
Boston's Central Artery/Tunnel project, begun in 1991, was originally priced near $2.8 billion. It finished in 2007 at roughly $14.8 billion, becoming America's most expensive highway project.
Massive cost overruns, a fatal ceiling collapse in 2006, and years of disruptive construction in downtown Boston.
The project became the standard cautionary tale for every U.S. megaproject since, driving demand for fixed-price and design-build contracts.
The Mobile Bridge faces similar geotechnical and cost risks along Mobile Bay, which ALDOT says pushed the program beyond $5 billion.
