An integrated analytical framework for assessing public transport equity using multidimensional accessibility metrics and spatial visualization

Public transportation is a critical urban infrastructure, whose equity and accessibility have a direct impact on residents' quality of life and social equity. To explore the disparities in access to bus services among different social groups, this paper proposes an analytical framework that integrates multi-dimensional accessibility metrics with equity assessment for different populations. The study employs a Weighted Average Travel Time (WATT) model to measure accessibility across three dimensions: walking, network-based, and integrated travel for different social groups, and utilizes ArcGIS for spatial visualization analysis. Furthermore, the study introduces the Accessibility Index (AI), Accessibility Differentiation Coefficient (ADC), and Transport Service Gini Index (GI) to evaluate the equity of service accessibility for different social groups. An empirical study of the public transport system in Baoji City demonstrates significant group heterogeneity in urban bus travel. The results indicate a strong positive correlation between the AI and ADC, while a strong negative correlation exists between the GI and both ADC and AI. This suggests that groups with higher accessibility, due to their greater mobility flexibility, are more likely to access high-quality service resources, resulting in a Matthew Effect that exacerbates spatial differentiation and social inequality. The analytical framework developed in this research offers a theoretical and methodological foundation for the accurate identification of public transport service inequities across demographic groups and for fostering the development of intelligent public transportation systems.