Spatiotemporal dynamics of ethnoracial diversity and segregation in Los Angeles County: Insights from mobile phone data

Ethnoracial segregation persists as a pressing issue in American cities. Understanding these issues is crucial for promoting social equity and justice, and planning more inclusive cities. Prior research has predominantly emphasized residential ethnoracial diversity but has often overlooked or inadequately addressed ethnoracial diversity and segregation in individuals' daily activities and places they visit, due in part to data limitations. This study leverages a dynamic measure of ethnoracial diversity and dominance at the finest spatial scale, specifically at the Points of Interest (POI) level and various temporal contexts. Using one month of privacy-enhanced mobile phone location data in Los Angeles County, California, this study explores ethnoracial diversity and spatial segregation simultaneously in POI visits in LA County. Our findings confirm that individuals' daily mobility in urban areas enhances ethnoracial mixing at activity locations. Empirical results indicate that the diversity of visitors to a POI is significantly higher than the neighborhood diversity where the same POI is located. A significant positive linear relationship was found between the neighborhood diversity of POIs and the diversity of visitors. About 34 % of the variance in the diversity of visitors to POIs can be explained by the neighborhood diversity of POIs. Our results also suggest significant spatial clusters of isolated/integrated areas regarding ethnoracial mixing in people's daily activity locations. Notably, the Hispanic or Latino population tends to stay in their own communities and experiences a higher level of segregation in their daily activity locations. The findings have significant implications for urban planners and policymakers to design targeted solutions and policies to promote social equity, integration, and equal access to public amenities and opportunities in urban spaces.