Socio-spatial equity in public transit system accessibility for slum and non-slum population in a developing mega city

Inequity in public transport system access affects the mobility and overall social and economic development of vulnerable groups, who rely on public transport for accessing jobs, healthcare, and education. Very few studies discuss the interplay between accessing the transit system and social vulnerability, especially in developing cities. This study presents a comprehensive framework for measuring social and spatial inequity in transit accessibility by integrating Public Transport Accessibility Levels (PTAL), transit gap, and social vulnerability. PTAL measures a transit supply component, while the potential transit-dependent population is the demand. The difference between transit demand and transit supply is the transit gap. The Gini index is used to quantify the degree of accessibility, while bivariate analysis is used to explore spatial patterns and critical areas where transit accessibility is most problematic. Additionally, a Social Vulnerability Index is designed based on socioeconomic indicators, which helps to address public transit needs beyond slum and non-slum classifications. PTAL analysis found that 31.8% of Mumbai’s population falls below the Good transit accessibility level. 52.2% of the population lives in high transit gap areas, and 13.6% live in transit deserts. It is observed that the accessibility to transit is not equitable for different population classes. For example, 32.5% of the highly vulnerable population is in low accessibility-high gap regions. Based on PTAL, transit gap, and social vulnerability, the study suggests targeted policy measures for reducing socio-spatial inequities in transit system accessibility. These findings can aid policymakers in improving transit accessibility and equity for vulnerable populations.