Urban density thresholds needed to support cost-effective fixed-guideway transit investments are investigated based on empirical experiences for metrorail, light rail, and bus rapid transit investments, drawing on experiences mainly in the U.S. Factors that interact with urban densities, such as car parking prices and transit service quality, are examined. High employment densities, combined with mixed land uses and walkable neighborhood designs, are found to be important, though by themselves insufficient, factors in predicting cost-effective transit investments in the world's most auto-dependent country, the United States. The need for articulating densities in rapidly developing cities, especially as part of bus rapid transit cities, is also discussed, drawing some several international case studies.
Professor Robert Cervero is the Friesen Chair of Urban Studies and incoming Chair of City and Regional Planning at the University of California, Berkeley, where he also directs the University of California Transportation Center (UCTC). He is currently an Overseas Fellow at Churchill College, Cambridge. Professor Cervero's research examines the nexus between urban transportation and land-use systems. He chairs the International Association of Urban Environments and the National Advisory Committee of the Robert Wood Johnson Foundation's Active Living Research Program, and serves on the Advisory Board of the World Economic Forum's Future of Urban Development Initiative. He also served on the IPCC (International Panel on Climate Change), contributing to the Fifth Assessment. He was recently ranked among the top 100 City Innovators Worldwide by UMB's Futures Cities and 4th highest among 850 urban planning academics in Google Scholar citations.