Feasibility analysis of freight-passenger integration using taxis in rural areas by a mixed-integer programming model

Rural areas generally have a small population and making it challenging to establish public transportation services as a commercial business. For this reason, the resulting business environment is such that it is unavoidable to reduce or abolish services if the number of users decreases, and the business sustainability becomes vulnerable. Given this background, one of the strategies for business sustainability is through freight-passenger integration, that is, the provision of both passenger transportation and freight delivery services. In particular, given that the taxi business can flexibly set destinations and travel times, it is highly likely that freight can be delivered in rural areas using taxis. However, there are many small taxi operators in rural areas. Because of this, when introducing freight-passenger integration, it is necessary to evaluate the feasibility of freight-passenger integration by determining whether it is possible to deliver all passengers and freight with a limited number of drivers and whether it is possible to obtain sufficient profit. Therefore, in this study, we focused on the characteristics of rural areas and constructed a model using mixed-integer programming that can reproduce the taxi operation resulting from the introduction of freight-passenger integration. Through the model, we evaluated the feasibility of freight-passenger integration based on profit and labor using taxi-operation historical data in a real-world area. Specifically, it was able to determine objectively under which conditions there will be a labor shortage and how much profit can be anticipated under such conditions.