Emergence of cooperative route-choice: A model and experiment of compliance with system-optimal ATIS

Advanced Traveler Information Systems (ATIS) aim to supply drivers with individually tailored information. User optimal information provision pushes the road network closer to the theoretical state of User Equilibrium (UE) instead of the System Optimum (SO). We investigate the effects on individual route-choice and consequent collective traffic states of an SO-based ATIS in a mixed within-between group design laboratory experiment. The experiment examines how implicit cooperation between self-interested participants emerges on a simple binary road network by providing them information in the form of system optimally allocated route recommendations and extrinsic incentives for compliance. Collectively, the recommendations were found to be a necessary condition for cooperation. Additional incentives in the form of penalties and rewards for compliance allowed cooperation to emerge much more efficiently. Individually, participants adapt to the new information by adopting four different coping strategies. Analysis of response time suggests that complex signals that include information on the recommended route coupled with incentives for compliance will result in more deliberation and higher rates of compliance. The implications for the behavioral implications on ATIS design and implementation are further discussed.