Simulation study of traffic car accidents at a single lane roundabout

In this paper, using the Nagel-Schreckenberg model, we numerically investigate the probability [Formula: see text] of entering/circulating car accidents to occur at single-lane roundabout under the expanded open boundary. The roundabout consists of N on-ramps (respectively, off-ramps). The boundary is controlled by the injecting rates [Formula: see text] and the extracting rate [Formula: see text]. The simulation results show that, depending on the injecting rates, the car accidents are more likely to happen when the capacity of the rotary is set to its maximum. Moreover, we found that the large values of rotary size L and the probability of preferential [Formula: see text] are reliable to improve safety and reduce accidents. However, the usage of indicator, the increase of [Formula: see text] and/or N provokes an increase of car accident probability.