Research On Coordination And Emergency Priority Control Of Urban Road Traffic Signals

With the acceleration of the urbanization in China,the car ownership of residents is increasing,and the phenomenon of urban road traffic congestion occurs frequency,which has a negative impact on urban residents’ travel and emergency rescue.Signal coordination control of urban area has become an important manner to alleviate urban traffic congestion and improve the efficiency of vehicles in the urban area.Aiming at the urban road area,this paper puts forward the signal coordination control method of urban area with Seeking Bands With Priority and the strategy of signal priority control under the emergency state in order to improve the target of traffic efficiency in urban area,based on the research status at home and abroad and the theory of signal coordination control.The core of urban area signal coordination based on Seeking Bands With Priority is to decompose the coordinated control of urban area signal into coordinated control of all arterials with priority,and calculate the green wave bandwidth of each arterials though each intersections so that it can improve the traffic efficiency rapidly.This method can determine the coordination sequence of arterials according to the arterial properties classification,speed,flow rate ratio,delay and other indicators of the arterials based on the qualitative and quantitative thinking.In the arterials to be coordinated,the coordination method will be determined according to the number of coordinated intersections.If there is one or no coordinated intersection in the arterial to be coordinated,the MAXBAND method is used to calculate the green wave bandwidth and offsets.If there are two or more coordinated intersections in the arterial to be coordinated,the public band across subareas is adopted to calculate the green wave bandwidth and offsets.Signal priority control of emergency vehicle is based on emergency situations such as fire,criminal and first-aid in urban area.In order to ensure that emergency vehicles can reach the accident place as soon as possible,the shortest route for emergency vehicles should be determined to ensure that emergency vehicles can pass through intersections without stopping.The green light adjustment strategy for emergency vehicles at each intersection includes nonadjustment,start in advance and delay ending.When emergency vehicles enter the corresponding section,different signal adjustment strategies are adopted according to the expected light color status of the intersection ahead,so as to ensure that emergency vehicles will not be affected by red light and queue vanishing when they arrive at the intersection,and pass through without stopping,so as to improve the execution efficiency of emergency disposal in the region.Based on the data of signal timing and flow at each intersection in the urban zone in front of an airport in Dalian,this paper verifies the method of Seeking Bands With Priority,and give a hypothetical scenario of the emergency control.The results show that the Seeking Bands With Priority method can reduce the average vehicle delay by 10.21%,the average vehicle stop times by 12.60% and the total fuel consumption by 4.61%,and optimize the vehicle delay,stop times and fuel consumption caused by signal setting in the urban zone.The case of emergency state can realize the emergency vehicle to carry out the task smoothly through each intersection without stopping based on the shortest path.The results show that the method of Seeking Bands With Priority can effectively improve the efficiency of vehicles in the urban area and reduce the goal of traffic congestion.Signal priority control of emergency vehicle could shorten the time of emergency vehicle carrying out tasks.The model of Seeking Bands With Priority and the priority control method of emergency vehicle are valuable for further theoretical research and engineering practice.