Connected vehicles generate new data streams that present promising opportunities for policymakers to monitor and learn from events and behavior. To explore what we can learn from how public entities leverage ubiquitous data streams for policy development and enforcement, we draw on a case study of the standard Mobility Data Specification (MDS) and its use by cities to regulate E-scooter operators. Our findings suggest that (1) the richness of real-time data changes the speed of policy revision, (2) data access enables moving some micro-decisions to the edge, and (3) policy will be formulated as fixed or flexible with different amendment rules.