Measuring Walk Accessibility and equality by National Walkability Index

Abstract: Accessibility is a dimension of transportation planning. This study investigates the associations between walking accessibility and the National Walkability Index (NWI). The findings demonstrate that the NWI has significant explanatory power in estimating the proportion of individuals choosing to walk as a mode of transportation at the census tract block group level. Consequently, an NWI-adjusted walking distance metric has been developed to quantify the variety of opportunities accessible from each block group population center. A case study conducted in Massachusetts employs both horizontal and vertical equity assessments, utilizing the Gini index and Lorenz curves. The results indicate that Regional Environmental Justice Plus (REJ+) communities are unevenly distributed across the state, underscoring the importance of identifying vulnerable groups within the REJ+ classification The scope of the NWI-adjusted walking metric is further extended to transit modes, incorporating different thresholds of walking distances people wiliness to travel based on NWI and General Transit Feed Specification (GTFS), which accounts for waiting and in-vehicle time. Additionally, the number of people living below the poverty level and households without vehicles are used to discover where the largest gaps in access exist across the state. The findings enhance the understanding of accessibility, providing actionable insights for policymakers to address transportation exclusion within REJ+ communities. furthermore, the analysis offers a scalable, nationwide framework to evaluate walking and transit accessibility equitably, which can guide the planning of walking environments, promote walking behaviors, and foster comfortable communities.