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 5/12 and 3/4. The metastable states are discussed in connection with the synchronized states observed in the traffic flow on expressway.