Research On Multiple Request Signal Priority Method For Emergency Vehicles And Buses

In reality,emergency vehicles mainly rely on warning lights and whistles to remind vehicles to give way,which is not effective and often encounters red light signals.Providing signal priority to emergency vehicles can effectively improve rescue efficiency.The implementation of bus priority policy and improvement of bus service level also require signal priority control.However,in the field of signal priority control,there is a lack of research that considers both emergency vehicle and bus priority.Therefore,this paper studies the multirequest signal priority method for emergency vehicles and buses.The main contents are as follows:(1)Research status analysis and basic issues.The research status of multi-request signal priority for emergency vehicles and buses at home and abroad is analyzed,and two signal priority control methods are proposed according to the shortcomings of existing research.The basic problems of signal priority control are introduced.(2)Rule-based multi-request signal priority method for emergency vehicles and buses.According to the constraints such as vehicle position,vehicle current speed and maximum speed,vehicle arrival time and adjustment range of green light end time,the corresponding speed guidance and signal priority control rules are established.The vehicle arrival is analyzed based on variable speed.For vehicles that do not need priority,carry out speed guidance.For vehicles that need priority,first calculate the vehicle priority according to factors such as vehicle type,passenger load factor,late delay and saturation,determine the priority phase,optimize the signal timing,and at the same time conduct speed guidance for the priority vehicles.The case analysis results show that the model can effectively reduce the traffic delay of emergency vehicles and buses at intersections.(3)Optimization-based multi-request signal priority method for emergency vehicles and buses.The green light duration of each phase in the dual-ring structure is taken as the decision variable.The traffic weights of emergency vehicles and buses are calculated,and the signal priority control model is established to minimize the weighted delay of emergency vehicles and buses.Under the premise of meeting the constraints of minimum green time and maximum cycle time,based on the rolling time window,the particle swarm optimization algorithm with penalty function is introduced to solve the model,and the optimal signal timing scheme is obtained.The case analysis results verify the effectiveness of the optimization model.In the context of the national strategy of prioritizing the development of public transport,the two methods proposed in this paper solve the priority conflict of multi-request signals through control rules and optimization models,respectively,and provide priority traffic schemes for emergency vehicles and buses,which have good practical value.