Study on influencing factors of urban expressway section reliability under emergency accidents

With the increase of urban expressway traffic volume, once a traffic accident occurs, it will pose a great threat to the normal operation of the section where it is located. In order to quantitatively study the impact of different factors on the reliability of the section in sudden traffic accidents, four influencing factors, including traffic volume, heavy vehicle mixing rate, number of lanes and lane width, are screened. Taking the average queue length, average number of stops and maximum queue length as the characteristic indexes of road reliability, the traffic data of Zhenwushan tunnel section of Chongqing Inner ring Expressway were collected. vissim simulation method was used to calculate the road reliability under different combinations of influencing factors. Then entropy weight method was used to calculate the contribution degree of each influencing factor to the road reliability. The results show that the weight of traffic volume is 0.66, which has the greatest impact on road reliability, followed by the number of lanes and heavy vehicle mixing rate, and the weight of lane width is 0.10, which has the least impact. The research results can provide reference for the safety guarantee and management of urban expressway in emergency.