Financial Viability Evaluation of Automated Bus Introduction to Wide-Area Bus Service: A Case Study of Five Prefectures in Central Japan with Remote Supervision Ratio as a Parameter

Regional public transport is an essential social infrastructure, and securing its sustainability is a pressing policy concern. Automated services are attracting attention as a response to driver shortages; however, their economic performance must be evaluated, even for public services. This study develops an evaluation framework that links demand changes induced by introducing an automated bus (AB) service with the resulting changes in expenditures, including labor-cost savings from remote supervision. The expected trip frequencies before and after introduction are estimated using a stated-preference survey (n = 2602) and a zero-inflated bivariate negative binomial model. Holding current subsidies constant, the framework derives the break-even acquisition cost—the introduction cost per vehicle at which the operator can maintain its current financial balance—for each supervision ratio (vehicles per remote operator). Applied to five prefectures in central Japan, the break-even cost increases nonlinearly with the supervision ratio. In Aichi Prefecture, supervising approximately four vehicles per operator reaches current price levels even at unchanged fares, whereas prefectures with lower revenue per vehicle cannot achieve comparable levels through higher supervision ratios alone. This framework provides a quantitative basis for price setting and supervision design when automated buses are procured as social infrastructure.