Quantifying systemic racial accessibility inequality in urban transit network

Abstract Urban transit networks are crucial for developing sustainable cities, yet uneven transit infrastructure distribution often leads to unequal access to urban resources. Prior studies utilize simple spatial metrics to measure accessibility, overlooking systemic inequality within transit networks and its real-world implications. Utilizing door-to-door travel information within a complex transit network, we probe racial inequality in transit-oriented accessibility to various urban resources and assess its impact on mobility behaviours. Our analysis reveals minority neighbourhoods endure consistently reduced transit-oriented accessibility to urban areas, job opportunities, and essential facilities by 15.2%, 37.3%, and 37.0%, respectively, compared to White-majority neighbourhoods. The uneven accessibility to urban areas exacerbates residential segregation by 32.1% relative to the equitable scenario. Regarding behavioural consequences, low accessibility subjects minority neighborhoods to constrained activity spaces, elevated unemployment risks, and extended travel distances to essential facilities. To inform potential mitigation policies, we conduct simulation experiments and discover that solely enhancing transit-oriented developments in minority-concentrated public housing districts can reduce current racial inequality by 8.8%. Our findings emphasize the imperative of prioritizing equity and inclusiveness in designing future sustainable transit systems.