The 15-min city vs. walkability indices: which is more strongly associated with health outcomes at the neighborhood scale?

In recent years both practitioners and scholars have paid increasing attention to the ways in which neighborhood design and the built environment influence public health. The concept of the 15- or x-minute city has gained momentum as a means of promoting transportation and land use configurations that support physical activity and healthier lifestyles. In this study we ask whether the 15-minute city concept is a useful indicator of health-related outcomes across five large U.S. metropolitan areas, and how its explanatory strength compares with the popular walkability metric Walk Score® and the EPA’s National Walkability Index (NWI). Spatial autoregression and geographically weighted regression were used to model the relationships between neighborhood accessibility/walkability and health outcomes in Boston, Chicago, Houston, Phoenix, and Portland (OR). Results suggest that both the 15-minute city and Walk Score® measures are more strongly associated with health outcomes relative to the NWI, though the strength and magnitude of the associations varied markedly by metropolitan area and health outcome. These findings contribute to a growing body of work on 15/x-minute cities by demonstrating the utility of time-based accessibility metrics as indicators of health-related variation across a diverse set of urban regions.