Statistical Properties of Individual Choice Behaviors on Urban Traffic Networks

Many transportation processes and behaviors, from traffic flow movement to crowd stampede and natural fluxion, are related to the action of agents. We have investigated and quantified the interplay between topologies and the individual behavior modes (unselfish and selfish) in equilibrium urban traffic networks. In this paper, the unselfish and selfish behavior correspond to the system optimum (SO) and user equilibrium in the traffic assignment. A significant finding is that the fractions of flow for two cases are constants in the minimum spanning tree where a large number of transport task is shouldered. In addition, we find that the upper bound of unselfish behavior is limited and ordinal for different network topologies which, therefore, indicates large investment on SO is not an effective method to alleviate the traffic congestion caused by selfish behavior. We report the phase transition from free traffic to congestion and derive a general scaling relationship between the congestion and the flow in arbitrary network topologies suggesting that the result might be practically useful for designing urban traffic networks.