Studies On Traffic Congestion Propagation Properties And Control Strategy Of Expressway Under Moving Bottleneck

In recent years,China's highway construction has made great progress and the new highways are dominated by multiple lanes.With the increase of the number of lanes,the traffic congestion caused by the inherent properties of the expressway has become less and less,but the traffic congestion caused by the interaction between vehicles and random disturbances is on the rise.The main reason is that China's expressways are dominated by mixed traffic,and large vehicles account for a relatively high proportion.Due to factors such as the performance of the large vehicle and the load,the speed is different from other vehicles,resulting in a large number of "mobile bottlenecks" on the expressway.Unlike fixed bottlenecks,the location of the mobile bottleneck changes over time,which has caused the congestion caused by the mobile bottleneck to be more complicated than the fixed bottleneck.Research on the law of highway traffic congestion propagation under the bottleneck of mobile bottle helps to reduce the traffic congestion caused by the "mobile bottleneck" on the expressway and improve the service level of the expressway.This paper takes the highway mixed traffic flow as the starting point,and uses the cell transmission model model combined with the three-phase traffic flow theory to study the impact of the current mobile bottleneck on the highway.Based on it,a control strategy based on variable speed limit is proposed.The main points of this paper are summarized as follows:(1)Based on the classical cellular transmission model,the three-phase traffic flow theory is introduced.The synchronous flow phenomenon is used to explain the traffic congestion under the moving bottleneck.The cell transmission model considering the synchronous flow phenomenon is proposed and numerical simulation is carried out.(2)The cell transmission model considering the synchronous flow phenomenon is added mobile bottleneck.Meanwhile,the effect of traffic flow caused by the mobile bottleneck on the highway is studied by adjusting the traffic bottleneck capacity,the movement bottleneck duration and the main line traffic respectively to observe the congestion delay,congestion scale and average travel speed in the traffic flow.The results show that the improved CTM model combined with the three-phase traffic flow theory can more accurately reflect the traffic flow characteristics under the mobile bottleneck.Mainline traffic,bottleneck capacity,and mobile bottleneck duration all have an impact on mobile propagation under the mobile bottleneck.When the main line traffic is higher than the capacity at the bottleneck,a mobile bottleneck will occur.The longer the mobile bottleneck lasts,the greater the impact on the traffic at the bottleneck.Under the influence of multiple mobile bottlenecks,the congestion scale and congestion delay at the bottleneck will further increase,and the average travel speed will be further reduced.(3)Aiming at the congestion problem under the influence of mobile bottleneck,and using variable speed limit control method,a variable speed limit Traffic control strategy is proposed by combining with the traffic jam mechanism under the mobile bottleneck,and the traffic flow characteristics of the congestion area under the mobile bottleneck,...