Traffic Flow Characteristics And Signal Control Strategy Of Single Intersection Under Adverse Weather

Signalized intersections are the main nodes for controlling and regulating urban traffic.Developing effective signal control schemes for them are important measures for efficiency and safety of traffic operation.In the adverse weather environment where drivers' sight is limited and the road is slippery,the braking distance of the vehicle will be longer and the reaction of the driver will be slower,resulting in a significant reduction in efficiency and safety of traffic,and adverse weather is severely affecting the urban traffic.It is very important to set reasonable time schedules in adverse weather.As the most basic unit in urban traffic signal control,timing of single intersection is the cornerstone of signal control research.Investigating the urban traffic signal control technology under the influence of adverse weather such as rain,snow,fog and haze has significant practical benefit.As signal coordinated control of trunk and area is difficult to achieve in adverse weather.Therefore,this thesis focused on signal timing of single intersection.Because the signal timing parameters are mainly affected by the characteristic parameters of traffic flow and the characteristic parameters of traffic flow will change under adverse weather,this paper first summarizes the status quo of the current research on the characteristic parameters of traffic flow and signal control technology under adverse weather.Secondly,road geometry,weather parameters,signal control parameters and traffic flow parameters were collected through surveillance video and field surveys.Five types of traffic flow characteristics were analyzed under adverse weather conditions and formulated on this basis.Based on the traffic flow characteristic parameters,we proposed the three-level classification criteria for adverse weather,and proposed a traffic signal control strategy for adverse weather,according to the saturation and duration.We determined the signal control strategy selection principles for all types of adverse weather traffic levels.Then,the changing patterns of the relevant signal control parameters under various weather conditions,including cycle time,yellow light time,red light time,and green letter ratio,were obtained based on investigated data.The scheme of intersection control with adverse weather was proposed.Finally,this article uses the intersection of Hanzhongmen Street and Jiangdong Middle Road in Nanjing as the isolated intersection control case.The VISSIM simulation software verifies the rationality of the proposed urban traffic signal control scheme.