Synergistic association between multimodal transport and demand-responsive transportation on daily walking steps: Quasi-experimental study in Senboku New-Town

• Investigate the effect of multimodal transport with DRT on daily walking steps. • Senboku-NT was analyzed as an example of a DRT operation area. • DRT has active travel effects of multimodal transport with buses. • The synergistic association is 1730.74 95% CI: 130.52, 3330.96 steps/day. • The multimodal transport is highly effective as first- and last-mile mobility. Demand-responsive transport (DRT) is expected to be a transport mode that solves first- and last-mile mobility problems. This study aimed to investigate the potential association of multimodal transport (buses or railways) with DRT on daily walking steps. Additionally, the reasons were examined in terms of changes in the frequency of multimodal trips and the reasons for choosing multiple modes. Senboku-NT was analyzed as an example of a DRT operation area. This study employed a quasi-experimental approach integrating the propensity score matching and difference-in-differences analysis. As a result, this study revealed that DRT is associated with daily walking steps through multimodal transport, including buses. Specifically, the average increase in daily walking steps was 1,730.74 95% CI: 130.52, 3,330.96 steps/day. The increase was shown to be significantly greater than that of DRT alone. In addition, the frequency of bus use increased significantly from before to during the DRT operation period. Moreover, few participants reported using multimodal transport combined with DRT for the purpose of improving their health. These results suggest that multimodal transport, combining buses and DRT, may be highly effective in promoting physical activity based on the population approach, by inducing more frequent public transport journeys regardless of users’ health intentions. In contrast, the multimodal transportation of railway and DRT did not significantly increase the number of daily walking steps and use frequency. Therefore, this study suggests that the potential synergistic associations of multimodal transport, including buses and DRTs, may be significantly greater for first- and last-mile mobility.