Zhan Guo studies travel behavior at the individual and household levels within the web of market forces, government policies, multimodal supplies, technology advances, and social trends. His main objective is to help policy makers manage urban growth, mitigate transportation congestion, and reduce greenhouse gas emissions from multiple perspectives such as land use planning, alternative modes, and value pricing. Guo's recent projects have focused on the impact of the built environment on walking experience in Boston, the weather impact on transit ridership in Chicago, and transfer behavior in the London Underground. His future research interests include car sharing, congestion pricing, parking policies, and household car ownership decisions. He is also interested in the interplay between rapid urbanization and motorization in China. Guo's research has been supported by the U.S. Department of Transportation through the University Transportation Center (New England), the Alliance for Global Sustainability, the Martin Society for Sustainability, the Future Boston Foundation, and transit authorities in Chicago, Boston, and London.