| Urban emergency rescue vehicles are an important line of defense to ensure the safety of people’s lives and property.The time when emergency vehicles arrive at the accident site after an accident is an important evaluation standard that affects the rescue quality.At present,China’s priority measures for urban emergency vehicles are mainly adopting "soft measures"such as laws and regulations,and using morality to restrain drivers in the whole society to avoid emergency vehicles in order to realize the priority passage of emergency vehicles in the process of performing tasks.However,in the actual traffic environment,the implementation effect of "soft measures" is not ideal,and it is not uncommon for emergency vehicles to wait in line at road sections and intersections,and social vehicles in front are not allowed to go.In addition,because urban emergency lanes are not designed and considered in urban road planning,the absolute priority of emergency vehicles in space cannot be guaranteed.Therefore,in order to improve the rescue efficiency of emergency vehicles and solve the problem that social vehicles do not comply with the avoidance regulations,this thesis studies the clearing method of urban emergency lanes by using urban ordinary lanes as emergency lanes in the intelligent network environment.Based on A*algorithm,a clearing algorithm of urban emergency lanes suitable for the characteristics of intelligent network environment is proposed,and establish a simulation system and calculate.The main contents are as follows:(1)This thesis introduces the research and development status of intelligent network technology at home and abroad,determines the basic environment of urban emergency Lane clearing model,and analyzes the disadvantages of the existing emergency vehicle priority measures.(2)The urban emergency lane clearing model under the intelligent network environment is proposed.In view of the defects of current emergency vehicle priority measures,an emergency lane emptying model is established by using the ordinary urban lanes as emergency lanes.The model takes the minimum impact on social vehicles as the goal,and the emergency vehicles passing through the road without stopping as the constraint condition.On the basis of the emergency lane clearing model,the concept of emergency lane trigger point is introduced to further reduce the impact of emergency lane on ordinary vehicles and optimize the position of emergency lane trigger point,thus putting forward an emergency lane clearing trigger point starting model.(3)An emergency lane clearing algorithm suitable for intelligent networked environment is proposed.The emergency lane clearing process is a process in which ordinary vehicles move from the starting point to the end point,and it is a shortest path process.For the shortest path,the mature and classic A*algorithm is introduced,and the A*algorithm is improved according to the characteristics of the emergency lane,so that the emergency lane clearing algorithm suitable for the intelligent network environment is obtained.(4)On the basis of emergency lane clearing model,the influence of queue length at downstream intersections on emergency lane clearing is further considered.The important parameter affecting queue length is signal control at downstream intersections.Then,the influence of various signal states on emergency lane clearing is discussed.Finally,emergency lane clearing model without queue and emergency lane clearing model with queue are established.The essence of the non-queuing emergency lane clearing model and the queuing emergency lane clearing model is to select the clearing objects,reduce the impact on ordinary vehicles and ensure the smooth operation of emergency vehicles.(5)Using Python programming platform to build simulation system and calculate.The starting model of emergency lane clearing trigger point can ensure the smooth passage of emergency vehicles through emergency lanes and reduce the impact on ordinary vehicles;In the environment of intelligent network connection,the queue length of downstream intersection has a constraint effect on emergency lane clearing;Under the same vehicle distribution state,the process of emptying emergency lanes with or without queuing is different. |
