Uncovering horizontal and vertical inequities of individual accessibility using mobile phone data

Reducing accessibility inequities among all individuals has been established as one of the sustainable development goals for fostering an equitable society. To address the limitations of conventional aggregated accessibility measures, this study quantifies individual-level accessibility inequities among 2.12 million phone users in Shenzhen, China, using mobile phone tracking data. The findings reveal significant horizontal and vertical inequities in individual accessibility, driven by both spatial disparities and interpersonal variations within residential areas. Human mobility significantly mitigates horizontal inequities by 33%-52% and vertical inequities by 40%-76% across three types of urban facilities, particularly benefiting users in regions with lower place accessibility. The study also identifies vulnerable individuals with low accessibility levels, emphasizing the joint influence of individual mobility and neighborhood facility availability. These findings provide new empirical insights into the mechanisms of accessibility inequities and offer methodological guidance for selecting appropriate accessibility measures in equity studies.