Research On The Evolution Of Network Traffic Flow

As the traffic network is generally in the state of disequilibrium characteristics, the urban traffic network always in the disequilibrium. In order to overcome the defects of traditional equilibrium theory, it is of great theoretical and practical significance to use the evolutional regularity of traffic flow with disequilibrium theory to reflect the process of traffic decision in practice. Based on disequilibrium theory in economics, this article studies evolutional regularity of traffic flow in traffic network. It mainly covers four parts: the characteristics of disequilibrium in traffic network, the travelers’ travel behaviors in traffic network, the dynamic evolutional models in traffic network flow, and the numerical simulations. The details are as follows:Firstly, the source and basis of disequilibrium traffic flow theory are clear and explicit by elaborating the definition of equilibrium and disequilibrium and quoting related notion of traffic assignment. The characteristics of disequilibrium traffic network are given out next and its similar features in economics are explained via combining the urban traffic characteristics and generally analyzing the affection of traffic function on time and cost. The regularity of travelers’ travel behavior, the affection on traffic and the relation of traffic flow in the whole traffic network are explored in the process from disequilibrium to equilibrium. All of these provide theoretical bases for the subsequent research on travelers’ travel behaviors and evolutional regularity of disequilibrium network traffic flow.Secondly, with the theory of disequilibrium traffic flow, the single traveler’s behavior are analyzed and then the rational behavior adjustment process(RBAP) when travelers choose the route are given out. The fundamental ideas of models are discussed, and the models of travel behaviors including five exceptional cases are exhibited, moreover, the ways of day-to-day traffic assignment are summarized. While all of these provide theoretical evidence for constructing dynamic evolutional models of disequilibrium network traffic flow.Thirdly, the dynamic evolutional models are built to describe the evolutional regularity of disequilibrum network traffic flow by using disequilibrium mechanism again and considering the adjustment function of travel cost and flow. And the stability of models are then analyzed by variational inequality and fixed point problem.Lastly, with the set adjustment parameters and initial conditions, the dynamic adjustment process of network traffic flow are modeled and described the process from disequilibrium to equilibrium by using numerical simulation on a network with single origin and destination. And the changes of disequilibrium are discussed in practical adjustment process of time-varying traffic flow and cost.