UC Davis Institute of Transportation Studies

To address roadway congestion problems, communities throughout the nation that are at risk for air quality problems are proposing major and costly beltway highway projects. In this study, an integrated land use and transportation model and an advanced travel demand model linked to a land allocation model are applied to evaluate different combinations of transit and highway investment alternatives, land use measures, and an auto pricing policy in the Sacramento region. Four policy and methodological questions are addressed in the simulation and evaluation of policy scenarios in this case study. First, what are the respective models' strengths and weaknesses, and what effect does this have of their evaluation of policies. Second, can transit investment, auto-pricing policies, and land use measures be just as, or more, effective in reducing congestion as highway alternatives and have the added benefit of improving air quality and protecting environmentally sensitive lands? Third, what is the relative significance of the results of the alternative scenarios simulated, given plausible errors in socio-economic projections? Fourth, can auto-pricing policies alone and/or in combination with other transit and land use policies significantly reduce vehicle emissions without imposing monetary losses on travelers? Finally, the implications of the answers to these questions are examined in the context of the transportation planning process.