Phase separation and evolution of one pulse jam in traffic flow

We study the transformation of a traveling jam with the pulse form in the single-lane traffic flow by using the optimal velocity model. The jam propagates with changing the initial form. It is shown that the pulse jam at the initial stage changes to the three types of nonlinear waves, appearing respectively in the three distinct regions in (Δx1,0,a)-space where Δx1,0 is the half of pulse strength at the initial stage and a is the sensitivity. Two waves of them form the plateaus. The value of the headway at the plateau is compared with the neutral stability and coexisting points. It is shown that the formation of plateaus is due to the phase separation in the dynamical jamming transition. It is found that the transition line between two waves forming plateaus is consistent with the coexisting line in the jamming transition.