Phenomenological Study of Dynamical Model of Traffic Flow

We show that the Car Following Model with Optimal Velocity (Optimal Velocity Model), which was proposed in our previous paper, is a successful traffic model in reproducing the characteristic features of observed traffic flow data. In our model the transition from free flow to congested flow occurs spontaneously by the collective motion of vehicles, which obey to the same dynamical equation. The observed specific discrepancy of traffic flow vs. car density graph is well understood in terms of the phase transition in our model.