It’s been 60 years since the 41,000-mile national interstate system was built. These roadways have served as the backbone of the U.S. transportation system for more than half a century. But the system is at the end of its useful life and needs major investment. How should these roadways be funded, maintained and used over the next 50 years?
The Federal government is wisely taking the time to give these questions some serious thought. Last month, the Transportation Research Board (TRB) held one of six national input sessions on its Future of the Interstate Study at the Metropolitan Planning Council (MPC). The presentations and testimony during the two-day session spanned a wide range of topics that could impact the system including: population trends, travel trends, freight trends, climate change, defense and economic development.
The role of this system in our national mobility is massive. The Interstate system comprises just over one percent of U.S. roadway miles but carries 25 percent of all auto travel and 50 percent of truck travel.
Unexpected trends have impacted our Interstate over the decades. What should we anticipate now?
Many unexpected trends have had major impacts on the system over the decades. For example, planners in the 1950s never anticipated how much interstate truck traffic would grow, which was largely a result of deregulation of the truck and rail industry in the 1980s. This makes us wonder: what should we be anticipating now?
Climate change may be one of the biggest factors affecting our transportation system in years to come, both directly and indirectly. Professor Don Wuebbles of the University of Illinois presented information on how severe weather events are increasing, including more heat waves, fewer cold waves and greater spring and summer precipitation in the Midwest.
Jennifer Jacobs, professor of Civil Engineering at the University of New Hampshire and lead author for the National Climate Assessment, interpreted how these changes impact the roadway system in terms of planning for climate and extreme events. For example, the transportation sector has not integrated climate considerations into maintenance and operations. We should expect more acute impacts such as flooding and pavement buckling. Chronic heat decreases pavement design lifespan so it lasts 15 years instead of 20. Electronic infrastructure is also affected by heat. What will the cost implications be if pavement needs to maintained more frequently due to climate change?
Many of the trends we have come to depend on will change. We can no longer plan the future based on the past
In contrast to recent trends of population growth on the coasts and in the south, population may shift away from areas that are experiencing sea level rise or excessive extreme weather events and alter national demands on the transportation system. If climate change results in the most fertile agricultural areas moving further north, freight shipment patterns will change in response. Many pressures on the National Highway System are expected to shift as a result of external trends, most of which are outside transportation planners’ control.
While transportation vulnerability studies have been conducted in many areas, few have looked at the multiple stresses facing the system as a whole. “We are planning for the future based on past performance. But the future will be different,” said Jacobs.
MPC published a 2010 report about congestion pricing. Its findings still prove relevant today.
At the state level we are doing our own interstate planning. I was pleased to join MPC President MarySue Barrett and Illinois Secretary of Transportation Randy Blankenhorn to give testimony to the TRB committee about planning and technical advances in Illinois related to the interstates. Barrett shared with the panel how an independent non-governmental agency like MPC can be helpful to regions in terms of sharing best practices and pushing innovation forward, as we have for issues such as congestion pricing and transportation demand management, among others. Forward-looking organizations unconstrained from the daily stresses of operating transportation systems play an important role in helping to think about future opportunities and challenges.
Secretary Blankenhorn shared how Illinois is undertaking its own Vision for the Northeast Illinois Expressway System, which should be completed by the late spring of 2018. Ours is the first state to conduct its own comprehensive, planning-level examination of the investments and management strategies needed to improve the condition and performance of the expressway system. The study will evaluate policy changes needed to effectively operate a cohesive, multi-modal regional transportation system. It will also evaluate the potential revenue generation from tolling and value capture given our state’s urgent need to develop sustainable revenue sources.
I highlighted how the Illinois Tollway is doing its own pilot testing for the future via the first Illinois implementation of a SmartRoad concept on16 miles of the Jane Addams (I-90). This segment includes real-time travel information, active traffic management, and a Flex Lane that is limited to only new Pace express bus services during congested periods to ensure transit reliability. The overhead gantries on the SmartRoad will be switched on within a few weeks and we’ll be watching to see if the benefits are as anticipated.
We need to think differently about the Interstate Highway System—and all transportation systems—moving forward.
The bottom line I took away from the Chicago TRB input session is that we need to think differently about the Interstate Highway System—and all transportation systems—moving forward. Many of the trends we have come to depend on will change. We can no longer plan the future based on the past—those days of steady 2 percent annual growth in vehicle miles traveled are over. Various demographic groups (i.e., Millennials, Baby Boomers) may make different transportation choices, such as driving less.
We need to think about all the factors that can affect our transportation systems, estimate future trends, consider various scenarios, and determine potential responses. Constant monitoring will be needed to see how trends are shifting and to track how we are progressing. We need to be vigilant in maintaining an equitable system that is accessible to all and in preventing unintended consequences despite the tantalizing promise of new technologies. There is no doubt that challenging and exciting days are ahead—there will be no shortage of interesting questions for transportation planners.