Unlocking the role of shared dockless e-scooters bridging last-mile gaps: A quasi-experimental study of metro rail transit in Los Angeles

One major challenge of a public transit system is first- and last-mile (FLM) connectivity. With the advent of smart technology and on-demand transportation services, shared micromobility is believed to provide a low-cost solution for bridging the first- and last-mile gap. However, several studies have arrived at mixed conclusions about the FLM achieved by shared mircomobility. This study explores the causal effect of shared dockless e-scooters on last-mile connectivity to public transit by controlling confounding variables, including built environment and socioeconomic status. The study employs a quasi-experimental design. This study defines last-mile connectivity, here, treatment effect, if e-scooter service areas near rail stations increase metro rail ridership after the introduction of e-scooter service. After matching pairs between treatment and control groups using propensity score matching, we use difference-in-difference regression to examine the causal relationship between shared dockless e-scooter service and ridership changes in public rail transit before and after e-scooter service. The findings indicate that the treatment effect, a higher e-scooter trip density around transit buffer areas, positively impacts monthly rail ridership. In conclusion, planning and transportation agencies can develop street design guidelines or transit-oriented development to encourage the active and safe use of e-scooters, thereby promoting better integration of shared dockless e-scooters with transit systems.