Once the backbone of the nation's transportation system, the nation's aging interstate highways are now overused and worn out, according to a new federal report. And failure to invest billions in modernizing the system will likely lead to more potholes, slower traffic jams, and increased costs to drivers and the nation's economy.
President Dwight D. Eisenhower signed legislation creating the interstate highway system in 1956. Since then, it has been "pivotal in shaping and supporting the country's demographic, spatial, economic, and social development," according to the study's authors. But now it is showing its age and the strain of overuse.
The report, "Renewing the National Commitment to the Interstate Highway System: A Foundation for the Future," was mandated by Congress and produced by the Transportation Research Board, which is part of the National Academies of Sciences, Engineering, and Medicine.
Between 1980 and 2015, vehicle miles traveled on interstates grew by more than 160 percent, compared with a 90 percent increase on all other public roads.
Interstate highways make up 1 percent of the nation's public roadway mileage today, but carry 25 percent of all vehicle miles traveled, including about half of all miles traveled by heavy trucks.
That's quite a load on the country's interstate highways, according to the study's authors.
"Most of them have exceeded their design lives and in many places are worn and overused," said Norman Augustine, former chairman and CEO of Lockheed Martin Corp. and chair of the committee that wrote the report. "These aging interstates are highly congested often times and in need of reconstruction."
Furthermore, the report indicates the entire interstate system is "threatened by a persistent and growing backlog of structural and operational deficiencies and by various looming challenges, such as the progress of automated vehicles, developments in electric vehicles, and vulnerabilities due to climate change."
For example, the study points out that more than one-third of interstate highway bridges are more than 50 years old and need to be repaired or replaced; highways need technological upgrades to accommodate electric and autonomous vehicles; and the system's infrastructure needs to be made more resilient to withstand threats from climate change.
In recent years, combined federal and state capital spending on interstate highway improvements totaled about $25 billion a year. Modernizing the country's interstate highways will cost an additional $20 billion to $50 billion a year, the report estimates. The study's authors recommend increasing the federal gas tax, which is the primary source of highway funding but hasn't been increased since 1993.
But the report acknowledges that more fuel efficient cars and advancements in electric, natural gas and other alternative fuel vehicles limit the long-term ability of the gas tax to pay for such significant interstate highway needs. So the committee also recommends a tax on vehicle miles traveled and increased tolling on interstates to pay help pay that hefty price tag.
Democrats in Congress and President Trump have said a big infrastructure package will be a top priority in 2019, with both sides saying it is one of the few issues on which they can agree. But a big sticking point is bound to be over how to pay for it.