Traffic flow behavior at a single lane traffic circle

Abstract

In this paper, we propose a stochastic cellular automata (CA) model to study traffic dynamic at a single-lane traffic circle of [Formula: see text] entry/exit points. The boundaries are controlled by the injecting rates [Formula: see text], [Formula: see text] and the extracting rate [Formula: see text]. Both the cases with and without the splitter islands of width [Formula: see text] are considered. The phase diagrams in the space [Formula: see text] are constructed and the density profiles are also investigated. The variation of the phase diagram with the traffic circle size [Formula: see text], the number of entry point [Formula: see text], and the time needed for drivers to change their exit willingly [Formula: see text] is studied. The results show that the phase diagram in both cases consists essentially of three phases namely free flow, congestion and gridlock. However, the large sized traffic circle shows better performance in the free flow phase, in contrary, the increase of [Formula: see text] enlarges the congestion and the gridlock phases. We have also found that the decrease of [Formula: see text] enhances the traffic flow situation in the traffic circle. Furthermore, as the [Formula: see text] increases, the free flow phase enlarges while the congestion and gridlock ones shrink.