lation that swept through the transportation sector during the last quarter of the 20th century led to even greater emphasis on efficiency as a criterion for transportation investments and, to a certain degree, led to a loss of redundancy and excess capacity in the sector as a whole. The dynamism of the U.S. transportation sector is unmatched in the world, and a major reason for the country’s high productivity and mobility. Another consequence of the emphasis on efficiency, however, is that costly security measures that promise unclear benefits or that impede operations are likely to be resisted or eschewed, whereas those that confer economic benefits are apt to be deployed and sustained.

  • Diversity of owners, operators, users, and overseers. Much of the physical infrastructure of transportation—from highways and airports to urban rail networks—is owned and administered by the public sector. But while the federal government helps fund construction, it owns and operates very little of this infrastructure.4 Most of it is controlled by thousands of state and local governments. While private companies and individuals own some fixed infrastructure (as with freight railroads), they function mainly as service providers and users, controlling most of the vehicles and containers that ply the networks.

    These public and private owners and operators are largely responsible for policing and securing the system, with the help of state and local law enforcement authorities and, for movements outside the country, foreign governments and international organizations. In addition to providing financial support for infrastructure (and now security for commercial aviation), the federal government’s main role is in promoting and regulating safety and environmental performance; supporting research and system planning; and monitoring and regulating transportation activity at border crossings and international gateways.5

  • Entwinement in society and the global economy. Trucks of all sizes distribute to retail outlets nearly all the products purchased by consumers and many of the goods and supplies used by industry and government. The rail, pipeline, and waterborne modes, along with large trucks, move products and commodities long distances among utilities, refineries, suppliers, producers, and wholesalers, as well as to and from ports and border crossings. In recent years, these transport modes have increased their efficiency to the point where just-in-time inventorying and manufacturing are commonplace. At the same time, the airlines have become indispensable in connecting cities all over the United States, and passenger airline service is essential to many areas of the country that depend on tourism and business travel.


The major exceptions are the FAA air traffic control system; roads on federal lands; and certain support services, such as the provision and maintenance of navigation aids (e.g., GPS).


A number of federal agencies—the individual modal agencies at the Department of Transportation, for example, as well as the USDA, EPA, the Customs Service, the Border Patrol, and the Immigration and Naturalization Service—have specific responsibilities in these areas.

The National Academies | 500 Fifth St. N.W. | Washington, D.C. 20001
Copyright © National Academy of Sciences. All rights reserved.
Terms of Use and Privacy Statement