Analysis of Supply Gap in Public Transit Considering Differences with Ride-Hailing

Public transit (PT) has always been essential to urban mobility. Although numerous metrics and assessments have been established for evaluating PT, they have focused solely on internal aspects of PT. However, PT systems do not operate independently, they face competition from multiple modes, resulting in a decrease in PT ridership. Therefore, external metrics are needed to capture the development level and appeal to passengers. This study proposed a framework to evaluate PT supply gap by using the travel attributes difference between ride-hailing (RH) and PT as external metrics. Taking Xi’an as the case study, the traffic analysis zones (TAZs) were segmented utilizing K-means clustering and multiple Thiessen polygons, and the PT supply score was determined by the independent weight–technique for order preference by similarity to ideal solution (TOPSIS) model. Furthermore, the PT supply gap was obtained by integrating the PT demand data. By analyzing the relationship between RH-PT differences and PT supply, we set external standards for evaluating PT development. The findings show a spatial pattern in the distribution of evaluation metrics, with the inner-city regions excelling the outer ones, and the western sections outperforming the eastern ones. The regions displaying lower PT supply scores are predominantly located in the city’s eastern outskirts. The PT supply gap is distributed both in the core and outskirts of the city, with walking distance being the primary contributing factor. The evaluation methods and external standards proposed by the study complement the existing evaluation system and support transportation managers in enhancing the attractiveness of PT.