For the past 30 years, Americans have addressed the environmental impacts of transportation through policy initiatives, planning and analysis, new programs, and new technologies. Accomplishments have been significant, but much remains to be done. During the next 25 years, significant growth and changes in the nation’s population and economy are expected to occur, posing major new challenges for transportation and the environment, but also offering important opportunities for advancement. Major new investments in transportation–environment research will be needed if these opportunities are to be realised. Many of the challenges to be met stem from America’s surface transportation systems, and in particular the motor vehicle–highway system. Private investments in the automobile and public investments in highways have brought Americans unprecedented freedom of movement. Most individuals today have access to automobiles providing them with the means to pursue interests, jobs, recreation, and schooling in ways and places that would have been out of reach for most Americans just a few decades ago. Goods move quickly and efficiently on truck and intermodal truck–rail systems, supporting economic growth. Americans have incorporated the automobile and truck into nearly all aspects of life—the economy, society, and popular culture. At the same time, the costs of current surface transportation systems are high. As driving levels increase, roads are becoming more congested, and valuable time is being lost in heavy traffic. Roads and parking are consuming large amounts of prized urban space. Residences and businesses are increasingly choosing to locate in the suburban fringe to avoid congestion, and the landscape is being fundamentally altered as new developments and new transportation facilities are built on land formerly devoted to farms and ranches, forests, and recreation. Thus traffic and roads are strongly implicated in many of the major environmental problems faced by the United States today: air and water pollution, heavy energy use, fragmented farmlands and habitat, wildlife and biodiversity losses, and community disruption. In turn, these problems are adversely affecting human and ecosystem health and the nation’s overall quality of life. In addition, the negative effects of surface transportation are unevenly distributed. The results of transportation investment decisions—facilities and networks—frequently have a disproportionate impact on inner-city neighbourhoods and older suburbs. Outward movement often proves costly to the communities and businesses that are left behind. People who cannot drive have limited access to jobs, services, education, and recreation. Older people, low income populations, persons with disabilities, and minorities bear a disproportionate share of these adverse impacts. If the current situation presents significant challenges for transportation professionals, the next 25 years will add to those challenges. The U.S. population is predicted to grow by 60 million, with most of that growth in metropolitan areas. Gross domestic product is projected to reach $29 trillion (approximately 1.5 times today’s levels in real terms). If current trends persist, the number of passenger miles travelled is predicted to grow even more rapidly than the population or the economy, swelling from 5 trillion in 2000 to 8.4 trillion in 2025. Americans will expect policy makers and transportation professionals to provide the transportation facilities and services needed to accommodate this growth efficiently, at low cost, and in a socially and environmentally responsible manner. The nation must find ways to deliver a transportation system that simultaneously promotes economic growth, adds to the health of communities and individuals, uses energy efficiently, is inclusive, and enhances the natural and built environments. (Author/publisher)
Abstract