Social dilemma structures hidden behind traffic flow with lane changes

Aiming to merge traffic flow analysis with evolutionary gametheory, we investigated the question of whether such structures can be formedfrom frequent lane changes in usual traffic flow without any explicit bottlenecks.In our model system, two classes of driver-agents coexist: C-agents (cooperativestrategy) always remain in the lane they are initially assigned, whereas D-agents(defective strategy) try to change lanes to move ahead. In relatively high-densityflows, such as the metastable and high-density phases, we found structuresthat correspond to either n-person prisoner dilemma (n-PD) games or quasi-PDgames. In these situations, lane changes by D-agents create heavy traffic jamsthat reduce social efficiency.