Diversity beyond density: experienced social mixing of urban streets

TL;DR

This study reveals that urban street diversity is influenced by factors beyond density, such as amenities and residential diversity, and that diverse streets tend to be safer, challenging traditional density-focused urban planning.

Contribution

It introduces the Experienced Social Mixing (ESM) metric at the street level and demonstrates multiple factors influencing diversity beyond density using mobile data.

Findings

Density explains only 26% of street-level diversity.

Adjacent amenities and residential diversity account for 44% of ESM.

Streets with more food businesses saw increased diversity from 2016 to 2018.

Abstract

Urban density, in the form of residents' and visitors' concentration, is long considered to foster diverse exchanges of interpersonal knowledge and skills, which are intrinsic to sustainable human settlements. However, with current urban studies primarily devoted to city and district-level analysis, we cannot unveil the elemental connection between urban density and diversity. Here we use an anonymized and privacy-enhanced mobile data set of 0.5 million opted-in users from three metropolitan areas in the U.S to show that at the scale of urban streets, density is not the only path to diversity. We represent the diversity of each street with the Experienced Social Mixing (ESM), which describes the chances of people meeting diverse income groups throughout their daily experience. We conduct multiple experiments and show that the concentration of visitors only explains 26% of street-level ESM. However, adjacent amenities, residential diversity, and income level account for 44% of the ESM. Moreover, using longitudinal business data, we show that streets with an increased number of food businesses have seen an increased ESM from 2016 to 2018. Lastly, although streets with more visitors are more likely to have crime, diverse streets tend to have fewer crimes. These findings suggest that cities can leverage many tools beyond density to curate a diverse and safe street experience for people.