His research investigates how urban development patterns intersect with neighborhood livability and environmental quality. These themes are evident in four overarching and interrelated areas of his empirical work: (A) impacts of transit-oriented development, (B) human activity patterns and environmental hazards, (C) urban inequality and access to opportunity, and (D) geographic analytical methods. His scholarship contributes to several literatures – transportation and environmental planning, environmental health science, public health, and geography – and expands each by helping explain how places and policies influence people, behavior, and community health. His work has received support from the California Air Resources Board, the California Department of Transportation, the California Endowment, the UC Transportation Center, and the UC Multi-Campus Research Program.