Below is a list of so-called megaprojects that are among the most expensive in U.S. history.

Highways The following list includes projects to build new highways or improve existing ones, including roadways, bridges, and tunnels. It includes only projects that are underway or completed. Additionally, projects with multiple independent segments (e.g., I-69 Indiana-Texas Extension, Trans-Texas Corridor) are not included, though individual segments may or may not make the list. Costs shown below exclude financing costs.

Date Price (nominal) Reference Year Price (ref. year) Price ( Inflation) Project 1956–present $425 billion 2006 $425 billion $ Interstate Highway System 1992–2006 $14.6 billionCentral Artery/Tunnel Project Website 1982 $8.08 billion $ Big Dig, Boston, Massachusetts 2000–2022 $1.4 billion 2022 I-5 - SR 16 Tacoma/Pierce County HOV Program, Tacoma, Washington (Interstate 5 in Washington) 2002–2013 $6.5 billion $ San Francisco–Oakland Bay Bridge East Span Replacement, San Francisco/Oakland, California 1988–2002 $5.0 billionTurnpike panel says high costs imperil Mon-Fayette, Southern Beltway projects, Pittsburgh Post-Gazette, April 27, 2007 Mon–Fayette Expressway, southwest Pennsylvania and northern West Virginia 2012–2019 $4.25 billion Alaskan Way Viaduct replacement tunnel, Seattle, Washington 2005–2020 (est.) $4.1 billion (est.)Louisville Bridges Cost Now $4.1 Billion, The Urbanophile, October 6, 2007 Ohio River Bridges Project, Louisville, Kentucky, and southern Indiana 2020-2025 (est.) $3.9 billion (est.)HRBT Expansion website Hampton Roads Bridge–Tunnel, Hampton Roads, Virginia 2001–2007 $3.6 billionFederal Highway Administration, Central Texas Turnpike Fact Sheet Central Texas Turnpike, area around Austin, Texas 2003–2008 $1.5 billion 2001 $2.8 billion (2008) $3.1 billion I-10 Katy Freeway Expansion (Interstate 10 in Texas) 2007–2011 $2.57 billionMaryland Department of Transportation ICC Website Intercounty Connector, Montgomery County, Maryland 1997–2029 $1.66 billion 2009 $2.2 billion $ North Spokane Corridor, Spokane County, Washington 1999–2008 $2.5 billionWoodrow Wilson Bridge Replacement Website Woodrow Wilson Bridge Replacement, Washington, D.C., Northern Virginia, and southern Maryland1959–1964 $320 million1964 $2.44 billionVerrazzano–Narrows Bridge 2015–2022 $2.3 billion (est.) I-4 Ultimate corridor reconstruction, Orlando, Florida 2008–2018 $1.8 billion (est.) Interstate 69 Extension SIU #3, Evansville to Indianapolis, Indiana 2010–2024 $1.6 billion (est.) Wekiva Parkway, Orlando, Florida 2001–2016 $1.4 billionCOG panel OK with $498M spike in Q bridge cost, New Haven Register, August 9, 2007 (est.) I-95 New Haven Harbor Corridor Reconstruction, New Haven, Connecticut 1991–2003 $1.2 billion E-470, Denver, Colorado 1933–2007 $37 million 1937 $37 million $ Golden Gate Bridge

Rail Date Price (nominal) Reference Year Price (ref. year) Price ( Inflation) Project Length 2015–2029 $64.2 billion (est.) 2018 $64.2 billion (est.) $ (est.) California High-Speed Rail (Phase 1) 520 miles (837 km) 2006–2025 $4 billion (est.) 2006 $12.4 billion (est.) $ (est.) Skyline 20 miles (32 km)1964–1976 $1.588 billion1976 $1.586 billion $Bay Area Rapid Transit (Initial System) 109 miles (175 km) 1863–1869 $124,548,691 1873 $124,548,691 $ First transcontinental railroad 1,868 miles (3,006 km)

See also Megaproject

References