The Interstate Highway System’s (IHS) development was begun nearly 6 decades ago. Initially justified in part on grounds of national defense, the IHS has contributed significantly and pervasively to our economic growth and quality of life.  While the 46,751 miles of highway comprising system’s basic configuration are now largely in place, many of the facilities that make up the IHS—including some 55,000 bridges, 15,000 interchanges, and pavement foundations for the system’s 210,000 lane-miles—are reaching or have already exceeded their economic service lifetimes.  Repair, reconstruction, and replacement of aging facilities represent continuing costs to keep the IHS safe and operational.  In addition, the composition and distribution of traffic on the system have shifted with time, so that new capacity is needed to support economic growth and relieve congestion in some places.  Similarly, the nature of the system’s role in national defense and domestic security has evolved, as has the legislation defining the federal role in developing, maintaining, and operating the system.

 

Congress has enacted a number of legislative initiatives in the 1970s and since to provide at least partial support for resurfacing, restoration, rehabilitation, and reconstruction of selected facilities. These initiatives (referred to as 3R and 4R, depending on their enabling legislation) supplemented the initial federal-aid highway programs that supported only new construction.  Periodic reports to Congress by the U. S. Secretary of Transportation provide the basis for congressional appropriations of funds to provide this support. 

 

Many officials at all government levels have suggested that the costs required to meet sustainably the nation’s demands for transportation services and to keep the system safe, operational, efficient, and secure are not adequately represented by the biannual conditions and performance reports prepared by the U. S. Department of Transportation. Research is needed to define comprehensively the costs for future preservation of the IHS and for selective expansion of the system to meet these demands within a context of a global economy, growing population, and national defense needs.  Those responsible for the IHS—the American Association of State Highway and Transportation Officials (AASHTO) and its member state departments of transportation (DOTs) , the Federal Highway Administration (FHWA)—envision a substantial study effort will be required, possibly conducted in multiple stages, and engaging other concerned agencies such as the Department of Defense, Department of Homeland Security, and metropolitan planning organizations (MPOs). The study would necessarily consider long-term as well as more immediate needs and the distinctions between the IHS and other parts of the nation’s surface transportation system.  The products of such work can inform policy makers and the public as they consider the future of the IHS.