Competition and coordination in public transport: A mode choice experiment

Public transport plays an important role in sustainable transportation by reducing traffic con-gestion and greenhouse gas emissions. This study investigated the competition and coordination behavior in public transport mode choice with both positive and negative externalities. Subjects participated in a mode-choice game in which they were required to choose between bus and metro. The externalities in one public transport mode were determined by its characteristics and how many individuals chose it. We examined two treatments with different amounts of information: less information and more information, corresponding to non-implementing and implementing advanced traveler information systems, respectively. We derived three different theoretical solutions (i.e., the pure-strategy Nash equilibrium, the mixed-strategy equilibrium, and the fair-reference point) as benchmarks to compare with the experimental outcomes, finding that the fair-reference point was achieved when more information was provided, whereas the pure-strategy Nash equilibrium was better to predict the choice behavior when providing less information. Furthermore, the comparison of the two treatments revealed the information paradox, indicating that information affected the public transport mode choice behavior, and more information might lead to worse outcomes. The spontaneous collective actions induced by less information and risk aversion could exert the benefits from positive externalities, thereby reducing travel costs compared with more information. Also, we adopted an adaptive learning model to reproduce the main findings in the experiment and exhibit simulated results under different levels of information provision, providing a parsimonious explanation for the information paradox.