Do Chilean cities have the right set of public transport modes?

Although there are various studies that evaluate the optimal design of public transport systems in radial structures, there are few that analyse which urban characteristics are relevant to recommend different public transport modes, particularly in small towns that lack the resources needed for such studies. Based on results from social cost minimization models, we classify small and medium-sized cities of Chile into three categories according to population, density, location of the city centre, and topography. For smaller towns (type A) subsidies to regular public transport seem unnecessary. In intermediate cities (type B) our models recommend promoting public transport services through shared taxis, a typical transport mode in Chilean cities in which a taxi carries up to 4 passengers on fixed routes or zones. Finally, in the largest cities in the sample (type C), it is recommended to subsidize the operation of bus services that produce less externalities than shared taxis, particularly congestion in the city centre. The methodology used can be extended to more complex structures and incorporate data from other countries, in order to formulate useful public policies in diverse contexts, in particular to address the lack of accessibility for vulnerable groups and zones. That said, transitions between categories are challenging for the governance of public transport systems and should be considered in further studies.