中文摘要：

降雨使得路面附着系数和驾驶员视距降低,容易造成交通事故,影响道路通行效率.为了研究雨天天气下车辆的换道行为,引入反映降雨对换道行为影响的路面附着系数参数和驾驶员反应时间参数,并进行量化分析,由此使得安全距离随降雨强度和车辆速度的变化而变化,在考虑前车和后车速度差对换道行为影响的基础上,建立了雨天高速公路车辆换道模型.仿真分析表明,在中密度区雨天换道率与晴天相比有明显下降,最大降幅约为25%;且改进模型再现了自由流、自由流在无外因影响下形成动态拥堵流以及阻塞流下车辆时走时停的现象;在中密度和高密度交通流中,雨天更易引起交通拥堵,其道路时空图中拥堵出现的频率和持续时间均相应增大,且车辆以低速度行驶的时间较晴天天气下高许多。

英文摘要：

Rainfall decreases road adhesion coefficient and sight distance of drivers, these can easily lead to traffic accidents which affect the road traffic efficiency. To study the vehicle lane-changing behavior under rainfall conditions, the adhesion coefficient parameter and drivers＇ reaction delay time parameter are introduced into the safety distance model. Based on the relationship between rainfall intensity and the water film thickness as well as the relationship among the road adhesion coefficient, water film thickness, and vehicle speed, the influence of rainfall on the road adhesion coefficient is quantified.And based on the relationship between visibility distance under rainfall condition and safe distance upon stopping sight distance, the influence of rainfall on drivers＇ reaction delay time is quantified. Therefore, the safety distance is different under different rainfall conditions and vehicle speed, it no longer is a fixed value like in other lane-changing models by quantifying the two parameters. The improved lane-changing model is established by considering the influence of the speed difference on vehicle lane-changing behavior; the speed difference is not only existing between the research vehicle and the adjacent lane vehicle ahead, but also between the research vehicle and the adjacent lane after the car.And the safety distance model including the two parameters is embedded in the improved lane-changing model by the lane-changing rules. For the three-lane traffic, the lane-changing rules which take into consideration the safety distance and the speed difference are established respectively for each lane, and the simulation analysis is conducted using cellular automata based on the above mentioned rules. Simulation results show that in the medium density the lane-changing rates in the rain condition are significantly lower compared with sunny days, the biggest drop is about 25%. Through comparison and analysis of the space-time diagrams and the speed-time curve of one vehicle at different traffic