This synthesis will be of interest to highway environmental specialists (particularly those concerned with assessing social and economic impacts), design engineers, planners, utility managers, and others responsible for the planning, design, and implementation of highway-widening improvements. Information is presented on the reasons for highway-widening projects, the nature of the projects, and the methods and practices for application of analytical techniques used to measure the potential or actual impacts of the projects on people and the physical environment. Mitigation measures are also discussed. This report of the Transportation Research Board describes the most recent widening projects as reported by states or other transportation agencies, as well as the most frequently encountered issues in highway widening. Selected examples of widening projects are included, as is some recognition of the need for additional information and research in the areas of social and economic impact measurement.

This new, expanded edition brings the story of the Interstates into the twenty-first century. It includes an account of the destruction of homes, businesses, and communities as the urban expressways of the highway network destroyed large portions of the nation’s central cities. Mohl and Rose analyze the subsequent urban freeway revolts, when citizen protest groups battled highway builders in San Francisco, Baltimore, Memphis, New Orleans, Washington, DC, and other cities. Their detailed research in the archival records of the Bureau of Public Roads, the Federal Highway Administration, and the U.S. Department of Transportation brings to light significant evidence of federal action to tame the spreading freeway revolts, curb the authority of state highway engineers, and promote the devolution of transportation decision making to the state and regional level. They analyze the passage of congressional legislation in the 1990s, especially the Intermodal Surface Transportation Efficiency Act (ISTEA), that initiated a major shift of Highway Trust Fund dollars to mass transit and light rail, as well as to hiking trails and bike lanes. Mohl and Rose conclude with the surprising popularity of the recent freeway teardown movement, an effort to replace deteriorating, environmentally damaging, and sometimes dangerous elevated expressway segments through the inner cities. Sometimes led by former anti-highway activists of the 1960s and 1970s, teardown movements aim to restore the urban street grid, provide space for new streetcar lines, and promote urban revitalization efforts. This revised edition continues to be marked by accessible writing and solid research by two well-known scholars.