Analysis of Traffic Characteristics of Dynamic Open Hard Shoulder Road Based on SUMO

In order to alleviate the congestion of expressway, based on Jingxiong expressway, the expressway traffic flow model is constructed by SUMO software. The secondary development is carried out through TraCI interface and python programming language. The speed standard deviation, lane changing speed, density, departure delay and operation delay are proposed as the traffic flow evaluation indexes of hard shoulder open sections, and the impact of different speed limit schemes on road traffic characteristics after hard shoulder opening is analyzed. The results show that hard shoulder running can improve the traffic capacity of Jingxiong expressway by 22.5%, and the optimal traffic volume range of hard shoulder opening is 8000–9800 pcu/h. With the reduction of the overall speed limit in the open section of hard shoulder, the standard deviation of speed continues to decrease, and the density and operation delay show an increasing trend. In the free flow state, the number of lane changes increases with the reduction of the overall speed limit of the road section. In the case of congested flow, the impact of the gradual reduction of the speed limit of the road section on the total number of lane changes is weakened. When the road is not congested, opening the hard shoulder can reduce the departure delay by 100%. After the road is congested, the departure delay is reduced by about 60% compared with that when the shoulder is not open.