This project provided supplemental funds for a study originally funded by the National Institute of Environmental Health Sciences (NIEHS) focused on obesity and the built environment. This Obesity and the Built Environment (OBE) supplemental grant added to a larger previously funded OBE grant that examined the associations between built environment features and physical activity, diet, and body size in three diverse samples of New York City-area residents. Columbia University researchers in this supplement developed and validated a version of the University of Maryland’s Urban Design Instrument (MUDI) that, rather than relying on in-person canvassing, uses geographic data on the built environment that is routinely collected by New York City governmental agencies. The resulting measures of urban design were added to the OBE-funded analyses of physical activity and obesity, providing an opportunity to test the association between urban design and health outcomes.