Impact of traffic lights on car accidents at intersections

Using the cellular automata Nagel-Schreckenberg (NaSch) model, we numerically study the impact of traffic lights on the probability of car accidents (P-ac) at the intersection of two roads. It is found that, the probability P-ac is more stable with variation of the green light (T) when the symmetric lights are adopted. Moreover, simulation results show the existence of a critical time T-c, below which (T < T-c) P-ac increases as the injection rate (alpha) increases, however, above which (T > T-c) the growing of alpha has for effect the decrease of P-ac. Furthermore, the decrease of P-ac is almost always accompanied by a loss of the flux, especially with asymmetrical lights. To overcome this problem, we proposed a strategy that can greatly increase the flux and keep the probability P-ac as small as possible, especially for the low and high injection rates.