The past three decades have brought sweeping changes to the i eld of transportation. In the United States and other developed nations, deregulation and greater reliance on markets and the private sector has helped to reconi gure the transport industries. The rise of intermodal goods movements and global commerce has produced efi ciencies of operation and a greater interdependence among transport modes. The fundamental importance of transportation in the modern society has been examined by rigorous analysis from a variety of disciplines: engineering, economics, geography, political science, information science, and sociology. Tradeoffs between competing values such as mobility, safety, efi ciency, equity, conservation, aesthetics, and historic preservation have helped.
