In this paper, the impacts of connected and autonomous vehicles (CAVs) on traffic efficiency and safety are numerically investigated. An on-ramp cellular automata (CA) model considering safe distance and interconnectivity is proposed and traffic flows under different CAV penetrations and distributions of CAVs are simulated. The outflow increases as the CAV penetration rate increases when the inflows are large, while the growth rate is insignificant when the inflows are small. The average speed distribution results also illustrate the positive impact of CAVs on traffic efficiency. In terms of traffic safety, the time-to-collision (TTC) results indicate that CAVs promote traffic safety in congested conditions. The criticality index function (CIF) results indicate that the mixed flow is still safe. We also proposed an evaluation index under emergency braking. Although CAVs have certain safety disturbance effects, they ensure that all vehicles are safe and alleviate stop-and-go traffic.

在本文中，对联网和自动驾驶汽车 (CAV) 对交通效率和安全的影响进行了数值研究。提出了一种考虑安全距离和互连性的入口元胞自动机（CA）模型，并模拟了不同 CAV 穿透和 CAV 分布下的交通流。当流入量大时，随着 CAV 渗透率的增加，流出量增加，而当流入量小时，增长率不显着。平均速度分布结果也说明了 CAV 对交通效率的积极影响。在交通安全方面，碰撞时间 (TTC) 结果表明，CAV 可促进拥堵条件下的交通安全。临界指数函数（CIF）结果表明混合流仍然是安全的。我们还提出了紧急制动下的评价指标。CAV虽然有一定的安全扰动效果，但能保证所有车辆的安全，缓解走走停停的交通。