Research On Three Phase Traffic Flow Modeling And Ramp Controlling Based On Cellular Automaton

The rapid development of transportation industry promotes the prosperity of the economy,improves the people's living standard.But it also brings a series of social problems,mainly including serious environmental pollution,frequent traffic accidents,and large areas of traffic congestion.Although the various countries of the world are taking active measures to solve these problems.But for many years practical experience at home and abroad shows that: only by increasing the traffic infrastructure and limiting the number of vehicles traveling can not solve the various traffic problem of existing fundamentally.This would require use the principle of system science to analyze the whole traffic system,find out the fundamental reason for the various traffic phenomenon and the internal mechanism of the mutual transformation between them,can be targeted to solve the problems of all kinds of traffic.This article by establishing the three phase traffic flow cellular automaton model which is more accord with the actual driving operation behavior,and applies it to the single entrance ramp system which the main line inlet flow rate and ramp inlet flow rate is fixed,finds the best control method.The research content of this paper includes the following two parts:(1)Traffic flow cellular automaton model based on action at distance of vehicleBy studying the existing cellular automata model of three-phase traffic flow,finds that there is a big difference when the vehicle in the process of slowing down between the real driving behavior and the modes.This paper makes the update rules of MVDE model as the foundation,redefining the action distance by leading into the vehicle speed,introducing impact which the speed and size relationship between the adjacent two cars into the magnitude and probability of deceleration of the rear vehicle,Modifies the update rules of MVDE model and establishes the new cellular automaton model(S-MVDE).Simulates density-flow curve and density-velocity curve of S-MVDE on the road with no traffic bottleneck structure under periodic boundary conditions and analyses which combines space-time evolution map traffic flow state of different density.Tests and verifies the S-MVDE model according to the characteristics of traffic flow in the Synchronized flow.At last,Simulates the traffic congestion mode which under open boundary conditions and there is an isolated ramp to form a traffic bottleneck structure on the road and contrasts with traffic congestion model on real road by Kerner observed.(2)Based on statistical ramp control researchBased on the analysis of the existed four main single ramp control methods(timing control,demand-the difference between the capacity control,acceptable gap control and ALINEA ramp control),proposed a new single ramp control method based on the theory of statistics,and the main road inlet flow rate as 0.1,the ramp inlet flow rate as 0.6 in a single ramp open boundary road structure using the method newly proposed simulates research.Based on analysis and comparison gets the best control cycle time.Analyzes and compares simulation results before and after the control,confirms the practicability of the new method finally.