Analysis On Traffic Flow Based On M/PH/1 Traffic Accidents Model

Aiming at two-way four-lane traffic system,we establish M/PH/1 traffic accident model and M/PH/1 traffic accident model with impatient waiting respectively to analyze the impact of different types of traffic accidents on traffic flow and provide decision-making basis for traffic management departments.With the help of VISSIM simulation software,the evaluation indexes of different types of traffic accidents are simulated to evaluate the impact of traffic accidents on traffic flow.The main contents are as follows.(1)The traffic accident model based on M/PH/1 is established.There are some limitations in the assumption of traffic accidents by using the traditional traffic flow analysis method,and there are few analyses of complex traffic problems at home and abroad at present.In this thesis,the M/PH/1 model is first time used to analyze the influence of traffic accidents on traffic flow.First of all,the traffic accidents are divided into accidents that do not need to be dealt with for a long time,accidents that need to be dealt with for a long time,and self-fault of vehicle and traffic system.Secondly,with the help of the generality of PH distribution,the M/PH/1 traffic accident model is established.The calculation formula of each evaluation index of the system are given,such as probabilities of vehicles continuing to drive,average numbers of times the vehicle arrives at a state,the first accident time,the average time,the probabilities of the traffic accident,the average number of accidents,the average loss of the vehicles,average rewards and penalties,then the results of the evaluation index are given through the calculation of an example,and the influence analysis on the traffic flow is evaluated.(2)The M/PH/1 traffic accident model with impatient waiting is established.Based on the assumption of(1),the common impatient waiting of the vehicle is analyzed.If the waiting time of the vehicle exceeds the impatient time,it will leave the queue.Impatience time is a random variable,and it is assumed that it obeys the exponential distribution.Similarly,the M/PH/1traffic accident model with impatient waiting is established.The calculation formulas of eachevaluation index of this situation are given,such as probabilities of vehicles continuing to drive,average numbers of times the vehicle arrives at a state,the first accident time,the average time,the probabilities of the traffic accident,the average number of accidents,the average loss of the vehicles,average rewards and penalties,and the influence analysis on traffic flow is evaluated by calculating the values of each index through an example.(3)With the help of VISSIM simulation software,the simulation environments of M/PH/1and M/PH/1 traffic system with impatient waiting are built respectively,and the evaluation indexes of different types of traffic accidents are simulated.Verify the effectiveness and rationality of the models proposed in this thesis.By comparing the average speed and queuing time near the location of the above accidents,the influence of traffic accidents on traffic flow is evaluated.