15 Most Expensive Public Works Projects in U.S. History

Photo by Zhang Kaiyv – Unsplash

Our public works department undertakes significant investments in infrastructure development to improve transportation and safety measures, and to promote economic development across various regions. Here are 15 of the most expensive public works projects in U.S. history, along with their estimated costs.

Photo by Robert92107 – Wikimedia Commons

California High-Speed Rail ($128 bn)

The California High Speed Rail was one of a kind ambitious project. The main idea was to connect major cities in California with high-speed trains. The project was estimated to be completed within a budget of $105 billion in March 2022. But it rose 22% to reach $128 billion in 2023.

Photo by Greenway Conservancy – Wikimedia Commons

Big Dig ($21.9 bn)

The Big Dig project in Boston, Massachusetts, was a massive undertaking that rerouted the Central Artery of Interstate 93 into a tunnel beneath downtown Boston​​. With a total cost of over $21.9 billion and a time of 14 years to be built, the project was aimed to alleviate traffic congestion and improve urban mobility​​.

Photo by Frank Schulenburg – Wikimedia Commons

San Francisco – Oakland Bay Bridge East Span Replacement ($8.6 bn)

The San Francisco – Oakland Bay Bridge East Span replacement was a huge project that was built to replace the earthquake-damaged eastern span of the Bay Bridge​​. It has an approximate project cost of $8.6 billion (adjusted for inflation). It was a complex engineering feat designed to enhance the bridge’s safety and longevity​​.

Photo by Harrison Leong – Wikimedia Commons

Second Avenue Subway Phase 1 ($5.6 bn)

Although this subway has been planned since the 1920s, it was never brought into action due to financial issues and was hence broken down into four smaller projects. The Second Avenue Subway Phase 1 is an 8.5 miles project that cost the authorities approximately $5.6 billion.

Photo by Carlos Alfonso – Unsplash

Central Texas Turnpike ($4.7 bn)

Costing $4.7 billion today, the Central Texas Turnpike toll road project in the area around Austin was designed to ease traffic congestion. It was also built to provide faster travel options for commuters and commercial vehicles​​. Although the construction was completed in 2002, it was opened to the public only in 2008.

Photo by SounderBruce – Wikimedia Commons

Alaskan Way Viaduct Replacement Tunnel ($4 bn)

The Alaskan Way Viaduct replacement tunnel was a $4.25 billion project. It replaced the Alaskan Way Viaduct with a tunnel in Seattle, Washington. The tunnel tried to enhance safety and waterfront aesthetics while maintaining a vital transportation corridor​​. The initial date of completion was 2015, which was later moved to 2019.

Photo by USGov-DOT – Wikimedia Commons

Interstate 69 Extension SIU ($4 bn)

The extension of Interstate 69 from Evansville to Indianapolis, still under construction, is estimated to cost $4 billion. It is a one-of-a-kind project that was recognized as one of six “Corridors of the Future” in 2008, and is slated for completion in 2024. The I-69 highway will cover 355.8 miles, stretching from Indianapolis, Indiana, northeast to the Canadian border in Port Huron, Michigan.

Photo by Censusdata – Wikimedia Commons

Ohio River Bridges Project ($3.6 bn)

With an estimated cost of $3.6 billion today, the Ohio River Bridges project was aimed to improve the transportation infrastructure around Louisville, Kentucky, and southern Indiana. The idea was to construct new bridges and revamp existing ones to assist smoother traffic flow across the Ohio River​​. The project was completed in 2016.

Photo by Andrew Bossi – Wikimedia Commons

Woodrow Wilson Bridge Replacement ($3.4 bn)

With a cost of $3.4 billion, adjusted for inflation, the Woodrow Wilson Bridge replacement project replaced the bridge connecting Washington, D.C., northern Virginia, and southern Maryland. The new bridge opened in 2008 and was designed to handle increased traffic volumes and improve safety​​. It carries a massive twelve lane traffic.

Photo by Formulaone – Wikimedia Commons

I-4 Ultimate Corridor Reconstruction ($3.3 bn)

This project was a major reconstruction of the Interstate 4 corridor in Orlando, Florida​​. It was a $3.3 billion project that included 50+ new bridges, 15+ interchanges, and widening of more than 80 bridges. The target was to enhance traffic flow, safety, and infrastructure resilience​​. The work for the project began around 2015 and was completed in 2021.

Photo by Sage Ross – Wikimedia Commons

I-95 New Haven Harbor Corridor Reconstruction ($2.8 bn)

Costing an estimated $1.4 billion, this reconstruction project for the Interstate 95 corridor in New Haven, Connecticut, intended to improve traffic flow, safety, and infrastructure longevity. It is a 7 mile stretch of highway that connects New Haven and Branford. Although the initial cost was pretty low, by the time the project was completed, the total cost rose to $2.2 billion in 2018 which is approximately $2.8 billion today.

Photo by Benoit Debaix – Unsplash

Hoover Dam ($2.7 bn)

The Hoover Dam was built during the Great Depression; it was completed between 1931 and 1936. With a total cost of $49 million to build, it was one of the most massive projects in the history of the United States. And if you add in the power plant and generators, the total cost was $120 million. Adjusted for inflation, the cost is approximately $2.7 billion today.

Photo by Famartin – Wikimedia Commons

Extension 470 ($2.5 bn)

E-470, the extension of Interstate 470, spans 47 miles (76 km) around the eastern edge of the Denver metropolitan area in Colorado. It was constructed in sections and completed in 2003, with a total cost of $1.5 billion. Adjusted for inflation, this amounts to approximately $2.5 billion.

Photo by Dougtone – Wikimedia Commons

Mon-Fayette Expressway ($2 bn)

The Mon-Fayette expressway is a highway project in southwest Pennsylvania and northern West Virginia​​. The expressway essentially includes four road projects. Although three of them are already completed, the fourth one is yet to be finished. The last project construction started in 2023. As per reports, the total estimated cost of the expressway is around $2 billion.

Photo by SPUI – Wikimedia Commons

Wekiva Parkway ($1.6 bn)

With an estimated cost of $1.6 billion, the Wekiva Parkway project in Orlando, Florida, aims to complete the beltway around the city and enhance traffic flow and also environmental protections​​. It is a 25 miles highway and was scheduled to be completed by 2022. The cost of the highway will be recovered by toll charges.


Leave a Reply