Study On Signal Control At A Single Intersection In Emergency Situations

In recent years,the rapid development of society has promoted the gradual expansion of city size,and the number of urban population and motor vehicles has increased sharply,leading to the increasingly serious problem of urban road congestion.More and more experts and scholars have focused on solving the problem of road congestion and expanding the carrying capacity of road network.Traditional methods,such as building new roads and restricting traffic flow,have had little effect in an era of rapid vehicle growth and population growth.The proposed intelligent transportation system has opened up a new way to solve this social problem.Researchers hope to use the existing science and technology and road facilities to reasonably distribute traffic flow and give full play to the potential carrying capacity of the existing road network.Due to the people-oriented concept of intelligent transportation systems and lower economic investment,make the road traffic signal control achieved good effect.We found that intersection signal control is the core of road traffic signal control in the study,because of intersection for the individual’s turn into crossing vehicles and shunt task,so the intersection signal control is the key and the difficulty.Emergency order point intersection signal priority control is the principal contradiction,to solve the problem of road congestion of emergency vehicles signal priority control directly about the daily life of the people and life safety,emergency vehicles signal priority control can improve the city’s ability to respond to emergencies,improve the road traffic environment,improve the urban residents’ life satisfaction,reduce the consumption of resources for motor vehicles,for the sustainable development of the state,give a lot of help.This paper mainly studies the signal priority control problem of single point intersection in emergency situation,and carries out research on the priority control of emergency vehicles at road intersections and the minimum total delay of social vehicles at intersections.The main research is:(1)Emergency vehicle signal priority control problem at single-point intersection.The paper makes a concrete analysis on the development of intersection signal priority control technology and intersection signal priority timing scheme,and elaborates the related theoretical knowledge of intersection signal priority control.The traffic state and traffic theory of road intersections under emergency condition are analyzed in detail and the related model of signal control of urban intersections under emergency condition is put forward.In this paper,the priority control model of emergency vehicle signals at urban intersections based on fuzzy Petri net is studied.Combined with the relevant theory of priority control of signals at urban intersections,the timing scheme of priority control of emergency vehicle signals at intersections is given.By determining the emergency vehicle flow ratio of the monitoring phase and the next phase and the membership function of the waiting vehicle length of the monitoring phase and the next phase,Petri net rule base is designed.Based on the fuzzy Petri net mathematical model,the actual execution time of green light detection phase is given,and the priority control method of emergency vehicle signal at road intersection is proposed.(2)Relevant research results of the total delay of social vehicles after emergency vehicles pass the intersection.Aiming at minimizing the total delay after the intersection of social vehicles,the dissipation of social vehicles after the emergency vehicles pass the intersection is studied,and the specific delay calculation formula is given,which can help solve the congestion problem of urban roads.Taking the signal control of four-phase intersections as an opportunity,the traffic flow ratio of emergency vehicles is fully considered in view of the total residence time of vehicles at the intersections,and the priority of traffic flow at different phases is given.Specific values of phase 1 and phase 3 are given at the four-phase intersection to simulate the entry state of emergency vehicles at the entrance road.The final results indicate that if the ratio of emergency vehicles to one inlet is fixed,but the ratio of emergency vehicles to another inlet is gradually increasing,the average delay of emergency vehicles at the road intersection is reduced due to the enhanced priority.