Traffic Capacity Analysis Of Urban Road After Traffic Accident Based On VISSIM

In recent years,the influence of urban road patency on economic development is becoming more and more obvious.While the transportation is convenient to people's life,it also brings some problems.There are phenomenons which lanes are occupied caused by traffic accident in the urban road,which affects the capacity of roads and causes inconvenience to people's travel.Therefore,it is necessary to study the traffic capacity of urban roads after traffic accident.At home and abroad,the research on urban road traffic capacity after traffic accident is limited,and there is no systematic research on the influencing factors of urban road traffic capacity and the changing process of traffic capacity after traffic accident.This paper is devoted to the study of urban road traffic capacity after traffic accident,and the main results are as follows:(1)Based on the traffic capacity model under normal conditions,the theoretical traffic capacity model and the actual traffic capacity model after the accident are established by theoretical analysis and simulation.The actual capacity in the example is calculated.Taking actual traffic capacity as evaluation index,in the actual case,the capacity of two kinds of lane occupancy situations is analyzed.It is found that traffic capacity is different when different lanes are occupied.By means of simulation,the influencing factors of traffic capacity when different lanes are occupied are analyzed.It is found that the difference in traffic capacity between two kinds of lane occupancy situations is due to the effect of the branch.(2)The formation process of the queuing phenomenon is analyzed by means of the traffic wave theory.Taking queuing length as evaluation index of traffic capacity,the traffic capacity of urban roads after traffic accident is analyzed.The vehicle queue length model of the accident section is obtained by the second-order theory and the law of flow conservation.The influencing factors of queue length after traffic accident are analyzed,and the queue length in the actual case is calculated.The whole and phase analysis of the queue length chang with time is carried out.It is found that the queue length is mainly affected by the vehicle flow,and the signal light at the intersection has a regulating effect on the queue length.(3)According to the analysis of the influencing factors of queuing length,three traffic optimization measures are proposed.According to the theoretical analysis,it is found that open residential district is more appropriate as the means of grooming.Taking the method of open residential district to traffic optimization of the actual road network.It is found that the driving speed of two directions increased from 9.614km/h and 27.732km/h to 30.027km/h and 37.083km/h respectively and the service level in two directions is upgraded from grade F and grade D to grade C,which shows that the open residential district has positive influence on the traffic capacity of the urban road after traffic accident.By means of simulation,the influence of internal road network modes on the traffic capacity of the urban road after traffic accident is analyzed.The results showed that the average travel time of the well residential district is 75.9s and 64.5s,and the average delay is 4.9s,which is greater than that of the cross residential district and the ring residential district.Therefore,it is recommended that the internal road pattern of the residential district avoids the well-shaped layout.The study results of traffic capacity analysis after traffic accident on urban roads in this paper can provide theoretical basis for road design,road planning and post-construction evaluation.