Car Accidents at the Intersection with Speed Limit Zone and Open Boundary Conditions

Using cellular automata model, we numerically study the traffic characteristics and the probability Pac of car accidents to occur at the intersection of two roads under open boundary conditions. Beside the free flow (phase I), jamming phase (phase III) and maximum current (phase IV) the phase diagram exhibits a new phase (phase II) which take place for β < 0.4 (β is the extracting rate). Moreover, the investigation of probability of the occurrence of car accidents has shown that the probability Pac increases with increasing the extraction rate β and exhibits a maximum at the transition point from the free flow to the congestion phase. However, when β exceeds the value 0.4, the probability Pac doesn’t depends on β. Furthermore, simulation results show that the speed limit zone (SLZ) can improve the road safety, where the probability Pac decreases with increasing length of SLZ. Likewise, we found that there is a critical injection rate αc, below which both roads must be equiprobable. However, above which, one road must always have priority in order to reduce the risk of collisions.