The Future of the Interstate Highway System
To make recommendations for the future of the Interstate Highway System the Commission should study the history of the Interstate System to see what can be learned, compare that with the challenges ahead, and consider AASHTO’s recommendations on what will be needed.
Historical Perspective
The System was designed in the pre-World War II period from the experience of a very different era. As Interstate construction began in the late 1950s, there were 65 million vehicles creating 600 billion vehicle miles of travel. Vehicle ownership had just begun to take off and long-distance trucking was still in its infancy. Fifty years later, there are over 240 million vehicles creating 3 trillion vehicle miles of travel on a highway system that grew by only 15 percent in the 50 years.
Major changes have taken place in the transportation environment for the Interstate. Some of these include transformations:
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From basic interstate commerce (farm to market, urban rural) to national/global commerce connections;
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From “old geography” (pre-sunbelt) to new geography of dispersed regional growth;
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From limited truck use to just-in-time logistics with large combination vehicles;
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From transcontinental troop and material movement to rapid “fort-to-port” mobilization;
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From uncongested new capacity to the need for congestion management; and
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From civil engineering standards to intelligent transportation systems and solutions.
Forecasts of the Challenges Ahead
Forecasts show that Interstate highway travel demand measured through vehicle miles traveled (VMT) will increase from 690 billion in 2002 to 1.3 trillion by 2026. Truck-borne freight is expected to double by 2035. Whatever redundancy and extra capacity that had been created when the system was originally built is being used up. As has been noted by FHWA, by 2020, 90 percent of urban Interstates will be at or exceeding capacity.
AASHTO’s Recommendations on the Future Interstate System
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Preserve the Current System. The first priority will be to preserve the 47,000-mile system which has been built over the past 50 years so that it lasts for at least the next 50 years.
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Enhance System Performance. Advanced ITS technologies and better system management techniques need to be utilized to reduce congestion, improve throughput, and increase system reliability.
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Expand Capacity to Meet Future Needs. It is vital that we are competitive in the global economy and meet America’s 21st Century mobility needs. We will need to add nearly as much capacity to the Interstate System in Phase II, as we did over the past 50 years in Phase I. Studies show there is a need to add as many as 10,000 miles of new routes on new corridors, 20,000 miles of upgrades to National Highway System routes to Interstate standards, and 20,000 new lane-miles on existing Interstate routes. These could include exclusive truck lanes and value-priced lanes. System improvement would also include correcting bottlenecks, upgrading interchanges, and improving intermodal connections.
- Reduce Growth in Highway Demand by Expanding the Capacity of Transit and Rail. The United States can neither afford for congestion to get as bad as forecasted, nor for traffic to increase as much as is estimated. In part, what is needed is a reduction in demand. Expanding the capacity of transit can help shift some local and regional trips off the Interstate and onto transit. Expanding the capacity of intercity passenger rail can help shift some long-distance trips off the Interstate and onto rail. Railroads must add to the capacity needed to at least continue to carry their current market share of freight so it does not shift to trucking and increases rather than decreases highway demand.
