Initiated by the Federal-Aid Highway Act of 1956 under President Dwight D. Eisenhower, the Interstate Highway System is widely considered one of the greatest public works projects in the first 250 years of United States history. For the heavy civil construction industry, it represented an unprecedented era of standardized road building, requiring all routes to be freeways with at least four lanes, controlled access, and no at-grade crossings.

“Our highways badly need modernization and expansion to accommodate today’s vastly increased motor traffic,” Eisenhower said when signing the legislation.

Seventy years later, that statement rings just as true.

Authorized at an initial $25 billion — equivalent to $300 billion today — for the construction of 41,000 miles over a 10-year period, the massive construction undertaking ultimately spanned 35 years and cost approximately $114 billion, or $937 billion in 2026 dollars.

Today, the sprawling network spans 48,890 miles and serves as the main arteries for much of the U.S., generating an estimated economic benefit of $65 billion annually considering fuel savings, road safety improvements, and congestion reduction, according to research by the Washington, D.C.-based nonprofit TRIP.

Celebrating its 70th birthday this year, the Interstate Highway System’s infrastructure is showing severe signs of its advanced age. A critical issue for modern roadbuilders is that most interstate segments still retain their original underlying foundations, meaning repeated pavement resurfacing yields diminishing returns and increasingly shorter periods of pavement smoothness.

In the Mid-Atlantic, intense utilization and aging infrastructure have heavily strained the network.

For instance, 18 percent of New Jersey’s major roads are in poor or mediocre condition. Driving on deteriorated roads costs New Jersey motorists $2.2 billion a year — $323 per driver — in the form of additional repairs, accelerated vehicle depreciation, and increased fuel consumption and tire wear. In addition, 6 percent of New Jersey’s bridges are rated in poor or structurally deficient condition, meaning there is significant deterioration to the major components of the bridge. A total of 53 percent of the state’s bridges were built prior to 1970. Many bridges that are 50 years or older may require significant rehabilitation or replacement.

In Pennsylvania, the aging of the major interstate network is also placing immense pressure on the vast local road network that supports it. Pennsylvania’s local roads and bridges carry 44 percent of all vehicle travel in the state. Currently, 26 percent of the local roads maintained by the Pennsylvania Department of Transportation are in poor condition. Additionally, 14 percent of the state’s local bridges are rated in poor or structurally deficient condition.

For contractors, modernizing the network will require a massive pipeline of upcoming work. Beyond simply replacing aging pavements, roadbuilders will be tasked with completely upgrading outdated interchanges, “right-sizing” lane capacity, and fundamentally overhauling safety features to handle the influx of both passenger and commercial freight.

“The Interstate Highway System was built with a vision that transformed how America travels and does business,” said Anthony Bednarik, Vice President of Design-Build/Major Pursuits at Wagman Heavy Civil and TRIP Board Member. “Meeting the demands of the next 70 years will require the same spirit of innovation and collaboration that created it. By investing in modern, resilient infrastructure, we can improve safety, strengthen freight mobility, and deliver transportation solutions that support growing communities and a competitive economy.”

“The Interstate Highway System is more than concrete and steel; it is a living symbol of American ambition, ingenuity, and unity,” TRIP Executive Director Dave Kearby said. “Built by a generation that believed in creating something bigger than themselves, these roads connected families, fueled commerce, strengthened national defense, and opened the country to endless opportunities. As we reflect on its 70th anniversary and America’s 250th, rebuilding this system is not just an investment in infrastructure; it is a chance to honor that legacy and ensure future generations inherit an America that still believes in building boldly for tomorrow.”

For more information and access to all TRIP reports, go to www.tripnet.org.

Lisa Mead is the Marketing and Partnership Director for TRIP, a national transportation research nonprofit.