Cellular automata traffic flow behavior at the intersection of two roads

The control of vehicles in urban traffic is a requirement to maximize the flow and to ensure the safety of traffic. Using the cellular automata Nagel-Schreckenberg (NaSch) model within a parallel dynamic update, we studied the effect of the intersection of two symmetrical roads, with typical periodic boundary conditions. It is found that the fundamental diagram depends strongly on the probability P of priority and the probability P-1 of changing the road at the intersection. Beside the free flow, the platoon and the jamming phases, the fundamental diagram exhibits a fourth new phase occurring for any value of P not equal 0.5, which disappears gradually as one increases the probability P, and disappears completely for P not equal 0.5. The effects of the braking probability P-b on the fundamental diagram and space time structures are also computed for different values of maximal velocities.