Users’ Willingness to Shift According to Interregional Bus Type Based on the Latent Class Mixed Logit Model: A Case Study in Seoul Metropolitan Area

In the Seoul Metropolitan Area of Korea, ongoing urban expansion continuously increases commuting demand toward Seoul, resulting in severe congestion in the urban core due to the large inflow of interregional buses. In response, the government proposed the introduction of a transfer-type interregional bus system as an alternative to alleviate downtown congestion. Transfer-type buses terminate at the Seoul boundary and rely on passenger transfers to other modes for access to the urban core. By shortening route lengths, this system enables reduced headways and increased service frequency. This approach can mitigate urban congestion. However, required transfers may generate user resistance, highlighting the need to analyze users’ willingness to shift. This study applies a latent class mixed logit model to stated preference survey data collected from 502 interregional bus users in order to capture heterogeneous preferences. As a result, users are grouped into three classes: transfer-avoidant, cost-sensitive, and time-sensitive. In all segments, more than half of respondents express a willingness to shift, with the highest level observed in the cost-sensitive group (64.3%). The class-specific choice models reveal that heterogeneity exists not only across segments but also within each segment. These findings indicate that a transfer-type interregional bus policy cannot operate uniformly across all users. Instead, a targeted strategy that simultaneously improves travel time and travel cost for subgroups with conversion potential is required. By systematically identifying users’ willingness to shift and heterogeneous response structures prior to implementation, this study provides empirical evidence to support the design of effective policies and operational strategies for transfer-type interregional buses.