He conducts research on travel behavior and the built environment; residential and workplace location choice; “smart growth” and municipal fiscal decision making; and the connections between public transportation, immigration and the economic growth of cities. Ongoing and recently completed research projects include studies addressing which U.S. transit systems succeed, and why; the implications of immigration trends for sustainable development and economic growth; the effects of dynamic pricing on occupancy and use of onstreet parking in San Francisco; and the relationships between residential location, travel, social interactions, and well-being.