A tale of three cities: A process tracing analysis of policy instrument choice when governing shared mobility

During the past decade, smart mobility services such as bike- and scooter-sharing have been deployed in cities worldwide. These deployments, typically done by private companies, have led to a wide range of policy responses by city governments, which have seldom been studied in the academic literature. In this paper, we classify the policy instruments that three city governments have used to steer the direction of such shared mobility services. We also identify and analyse local policymakers' motivations and constraints for selecting these instruments. Finally, we also carry out a process tracing methodology to see if existing theories of policy instrument selection fit the shared mobility policy space. To do this, we carried out three case studies of cities in which shared mobility services had been introduced by private companies: Bogotá, Paris, and Los Angeles. We documented a total of 53 unique instruments used by the three cities. We also identified that instrument selection at the city level can be constrained by national-level circumstances, but when these change, city governments adapt their instrument selection strategy. We also found that when no national policy constraints exist, policymakers try to select instruments that balance the efficacy of the instrument against its legitimacy.