The Congestion Mitigation and Air Quality Improvement (CMAQ) program was enacted as part of the Intermodal Surface Transportation Efficiency Act (ISTEA) of 1991 and reauthorised by the Transportation Equity Act for the 21st Century (TEA-21) of 1998. After nearly a decade of the program’s operation, congressional sponsors are interested in knowing whether it has been effective and whether its projects are cost-effective relative to other strategies for reducing pollution and congestion. Their questions were summarised in a request to the National Academy of Sciences for a study to evaluate the CMAQ program, included as Appendix A. In response to this request, the Transportation Research Board (TRB) of the National Research Council (NRC) formed a committee of 16 experts chaired by Martin Wachs, Professor of Civil and Environmental Engineering and City and Regional Planning, and Director of the Institute of Transportation Studies at the University of California at Berkeley. Committee members have expertise in the areas of transportation and air pollution modelling, transportation demand analysis, urban planning, air chemistry and air quality monitoring, vehicle emissions (mechanical engineering), economics, environmental policy and program evaluation, human exposure assessment, and ecology. They also represent various institutional perspectives — metropolitan planning organisations, state departments of transportation, research institutes, foundations, and universities. The following study tasks lay at the core of the requested performance review: • An assessment of the effectiveness of projects funded under the program, including quantifiable and qualitative benefits; • An estimate of the efficiency or cost-effectiveness of projects funded under the program, including their cost per ton of pollution reduction and per unit of congestion reduced; and • A comparison of the cost-effectiveness of emission reductions achieved by CMAQ-funded strategies with that of other pollution reduction measures. The committee welcomed the focus on cost-effectiveness and adopted a broad-based approach in response to its charge. It commissioned an analysis of the Federal Highway Administration-sponsored national database of all CMAQ-funded projects since the program’s inception to examine spending trends over time and by region. The database was also reviewed as a potential source of information on project-level estimates of emission reductions and costs. The analysis was conducted by Harry S. Cohen, independent consultant, and is presented as Appendix C. Two papers were commissioned—one to review the literature on the cost-effectiveness of transportation related strategies eligible for CMAQ funding, and the other to examine the cost-effectiveness of alternative strategies for controlling pollution, primarily through technology advances to meet new vehicle emission and fuel standards. The first review was undertaken by J. Richard Kuzmyak, transportation consultant, and the second by Michael Q. Wang of Argonne National Laboratories; the results are presented in Appendices E and F, respectively. The interpretations and conclusions presented in these appendices are those of the authors; the key findings endorsed by the committee appear in the body of the report. The committee also conducted five in-depth case studies in selected metropolitan areas to gain insight into how the program operates in practice, the role of government agencies in program implementation, and the more difficult-to-measure qualitative outcomes of the program. The detailed results of these case studies can be found in Appendix D. The committee supplemented its expertise with briefings at its meetings from state and local recipients of program funds, public interest groups, and other knowledgeable parties. (Author/publisher)
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