Metastable flows in a two-lane traffic model equivalent to extended Burgers cellular automaton

A two-lane cellular automaton traffic model equivalent to the extended Burgers cellular automaton has been proposed, and evolution equations for cars on the two-lane road are obtained. Configurations of cars on the road are simulated by using the equations and many metastable local congested states are found in two-dimensional region on density-flow diagram. There are three typical states in the congested states: The first is that cars advance by stop- and go-flow on their own lanes without lane-change and values of the flow are stable in time. The second is that cars change the lane periodically with several time-steps. The third is that they advance changing the lane that induces fluctuating of the flow with extremely long period. This fluctuating flow exists in wide range between car densities 512 and 34. The metastable states are discussed in connection with the synchronized states observed in the traffic flow on expressway.