Study On Strategies Of Inputting Multi On-ramps Coordinated Control Signal For Urban Expressway Based On CAM Simulation

As the basic means of urban expressway management and control,coordinated control is the primary task: under specific conditions,how to apply control signals within a wide range.This is because the relative confinement of urban expressways makes the propagation of congestion very fast,and there are limited paths available for vehicles in the affected sections of the upper reaches of the affected area,and the impact range will be more extensive,especially when transport needs such as commuting to work are high.In addition to serious traffic accidents such as the implementation of the road closure,under normal circumstances,traffic congestion cannot be ignored,so that vehicles cannot pass quickly and may cause a wide range of congestion over a long period of time.In the case of over-widening the scope of control,a large number of vehicles transfer to the general urban road,causing the city's general road area more congestion,this is not the purpose of traffic management.At present,the research on coordinated control of continuous traffic flow does not involve the control signal application strategy.Based on this,this paper studies the urban expressway as the research object,through the investigation and analysis of the influencing factors of the possible adjustment of the driver's path,determine the probability of driver's path change under different conditions,establishment of coordinated control of urban expressway CAM(Cellular Automaton Model),the traffic flow characteristics of different ramp coordinated control signals are simulated,and the optimal strategy is determined to provide some decision support for traffic management.The main work can be summarized as the following.(1)Analysis of urban expressway traffic system.This paper describes the system composition and characteristics of urban expressway in detail,and analyzes the impact of environmental factors on the expressway.The time distribution and spatial distribution of urban expressways traffic demand are summarized,and the traffic flow characteristics and driving behaviors of urban expressways under different traffic conditions are explored.(2)Investigation and analysis on the driving behavior of urban expressway.Based on the analysis of the driver's reaction when the urban expressway is in traffic jamming state and stated preference survey(SP)investigating,the probability distribution of the driving behavior adjusting and possible path change for a driver in each state was determined.(3)The establishment of cellular automaton model for urban expressway.Based on the symmetric two-lane Nagel-Schreckenberg(STNS)model,a cellular automaton model of coordinated control section on urban expressway are established,combined with the results of the questionnaire survey,where the driving behaviors are described accurately.The characteristics of traffic flow were discussed via the simulation experiments by using the different ramp control strategies upstream of jamming point.(4)The effects of different traffic demand on road flux were analyzed by using some control signal methods,respectively.The results of the examples indicate the following: the multi-ramp coordinated control is a basic tool of management for urban expressway;the impact of congestion can be reduced at the utmost only by using the strategy of inputting different control signals under different traffic demands and states.Furthermore,the goal of enhancing road actual traffic volume can be realized.