Assessing the (in)equality of an x-minute city accounting for human mobility patterns

Developing x-minute cities has become a global effort since the proposal of 15-minute city by Carlos Moreno who has reworked several earlier planning theories and practices. Against this background, a burgeoning body of research literature has proposed quantitative methods for evaluating cities’ progress towards the achievement of an x-minute city. However, current approaches predominately focus on the density and proximity aspects of x-minute cities, but underrepresent other critical aspects including the equality of x-minute cities. Human mobility patterns are also not accounted for in current approaches, leading to potential bias in evaluation results. This study bridges these research gaps by proposing an equality assessment framework that explicitly accounts for disparities in mobility patterns of different population groups. A mobility-aware accessibility metric is first proposed and then used as the basis for assessing the (in)equality of urban service provision across space and population groups. We use a full month of mobile phone signaling data in the city of Nanjing, China to obtain the activity patterns of different population groups. The case study suggests that not accounting for human mobility would lead to an overestimation of accessibility and accordingly a possibly too rosy view of achieving the x-minute city goal. In addition, the measurement of x-minute cities is sensitive to location, time, service types and population groups. These results have implications that developing an equitable x-minute city should move beyond the overly simplified proximity-based metric, but further accounts for different population groups’ varying mobility patterns and their interactions with urban services.