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.

The challenge now is ensuring this vital transportation asset continues to deliver those benefits for decades to come.

“The Interstate Highway System has supported New England’s economy for generations, but maintaining that success requires more than preserving what we’ve built,” said Parker Mills, Vice President at Peckham Industries and TRIP Board Member. “We have an opportunity to make smart, forward-looking investments that improve safety, reduce congestion, and strengthen the transportation network that businesses, workers, and families rely on every day. Careful planning and responsible execution will ensure these projects deliver lasting benefits for decades to come.”

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 New England, the region’s harsh freeze-thaw cycles and intense utilization have heavily strained this aging network.

For example, according to the latest report from TRIP, 34 percent of New Hampshire’s major locally and state-maintained roads and highways are in poor or mediocre condition. Driving on these deteriorated roads costs the average New Hampshire motorist an additional $551 annually in vehicle operating expenses. The state’s bridges also face significant challenges: 8 percent are rated in poor or structurally deficient condition, while 53 percent were built in 1969 or earlier.

Similar conditions exist throughout New England. In Maine, 33 percent of major roads are in poor or mediocre condition, costing motorists an estimated $562 million annually — or $527 per driver — in additional repairs, accelerated vehicle depreciation, increased fuel consumption, and tire wear. Conditions are even more pronounced in Rhode Island, where 71 percent of major roads are in poor or mediocre condition. Deteriorated roads cost Rhode Island motorists approximately $705 million each year, or $925 per driver, in additional vehicle operating costs.

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. In New Hampshire alone, freight moved by trucks is expected to increase 50 percent by weight and 81 percent by value by the year 2050.

“The resources being dedicated to modernizing the Interstate Highway System represent a significant opportunity for New England,” said Jim O’Brien of Bothar Construction and TRIP Board Member. “By prioritizing projects that deliver the greatest long-term value and maintaining a disciplined approach to project delivery, we can improve mobility, strengthen economic competitiveness, and ensure this vital infrastructure continues to meet the needs of future generations.”

“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.