Evaluating the distributional impact of urban rail improvements: Logsum accessibility measures incorporating income class and household type

• Estimate mode choice parameters by income class and household type • Apply logsum-based accessibility to assess Tokyo rail improvement benefits. • Work-trip benefits rise with income; variation narrows at mid-to-high levels. • Non-work trip disparities are greater, driven by VTT and household travel patterns. • Provides practical framework for equity-focused evaluation of urban rail projects. Recent discussions on transportation project evaluation have increasingly emphasized the importance of incorporating equity considerations. This study developed a travel behavior model that incorporates individual attributes and empirically assessed the distributional impacts of urban rail improvement projects in the Tokyo metropolitan area. Travelers were classified in this area into 24 attributes based on four income classes and six household types, and we estimated mode choice models for home-to-work and home-to-private trips. These models were then used to calculate the logsum accessibility measures, to predict user benefits from urban rail projects completed in 2019 and 2023. Distributional analyses revealed that for home-to-work trips, the median user benefit increased with income, but the interquartile ranges remained similar across most income groups above two million JPY/year. For home-to-private trips, benefits are higher for households with only one or two workers or for higher-income groups, reflecting greater variation in travel behavior and the value of travel time.