The models from the study calculated that if travel on the system grows at a modest pace comparable to the forecast U.S. population, transportation agencies will need to invest an average of $15 billion per year for improvements. These investments would need to be considerably larger if travel on the system grows at a pace closer to recent historical averages.
“An approximation of the total state and federal spending that will be needed to renew and modernize the Interstates over the next 20 years averages $45–70 billion per year,” according to the report. “The figures in this range are 2 to 3 times higher than current spending levels, and even 50 percent higher when only considering the outlays that will be required for the pavement and bridge upgrades that can be projected with higher confidence.”
The study also outlined a “blueprint for action” that makes 10 recommendations based upon the extensive research findings. Some of those suggestions include:
- Create an Interstate Highway System Renewal and Modernization Program (RAMP) by Congress that is focused on reconstruction deteriorated pavements, bridge infrastructure, adding traffic capacity and improving resiliency.
- Address current and emerging demands to extend the Interstate System’s length and scope of coverage, and to remediate economic, social and environmental disruption caused by highway segments overly intrusive to communities and not vital to network and intermodal traffic.
- Join with states to assess the foundational integrity of the system’s pavements and bridges, and identify where full reconstruction is needed.
- To pay for RAMP, increase the federal motor fuel tax to a level commensurate with the federal share of the required investment, and adjust the tax as needed to account for inflation and changes in vehicle fuel economy.
- Lift the ban on tolling of existing general purpose interstate highways.
- Start planning the transition to more automated and connected vehicle operations.
“Today, the nation is experiencing, and can anticipate, new expectations for the system’s condition, performance and use,” the report stated. “Meeting those expectations will require the same forward-looking outlook and commitment that informed the system’s creation—a rededication to that original vision that reshapes and reequips the system to serve generations to come.”
The TRB study was conducted by a committee with balanced expertise in transportation issues, drawing from information provided by the highway industry, including highway owners, operators and users of the system, associations, private-sector stakeholders, and academia, among others. Research began in December 2016, and the completed 649-page book was released in late 2018.
Visit the TRB website to order or download the book.
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