Study On The Optimization Method Of The Ramp Control For Freeway

With the rapid development of economy and society in our country and theincreasing size of our city，the number of vehicle is growing rapidly. The capacity ofurban roads，especially mega-cities have begun to cannot meet the traffic demandseriously. The freeway with fast，comfortable， high-capacity characteristics haveattracted a number of city builders， it has played important role to providehigh-capacity transport corridor，shielding transit traffic，regulate urban road networkstructure and optimization of land use layout. However，the continued rapid growth oftraffic demand is weakening this income，the problem of traffic safety and congestionproblems began to highlight and increasingly serious. Freeway in many cities hasbeen dubbed “the flow of parking”. As an important means of freeway trafficcontrol，ramp control has been proved to be a very effective way to solve the problemfast road traffic congestion，so the Urban Freeway algorithms and related theoreticalresearch is necessary and meaningful.Expressway on-ramp control mainly includes two aspects: the entry and exitcontrol. Through the on-ramp to control the on-ramp vehicle， can reduce theinfluence on the mainline vehicles from two aspects of the quantity and time， thisway can ensure the safety of expressway and operation efficiency. Through the exitramp control， reduce the influence of the downstream adjacent intersections， it canensure the safety of expressway traffic smooth out the at the same time， reduce thedisturbance to the connected road. In addition， through the ramp and adjacentintersections coordinated control can improve the control effect， make the globaloptimal.According to the current hot issues in the study of expressway control system，this article study from the ramp control and the coordination control of two adjacentintersection aspects， proposed under the condition of short-term traffic flowprediction on-ramp control model based on fuzzy theory， analyzes the ramp andadjacent intersections coordinated control strategy， using the simulation verified theeffects of model and strategy. This article main research content is divided into thefollowing five parts:（1） Through reading a large number of literature， summarizes the researchstatus of expressway control system， and puts forward the main research results ofcurrent research ideas， analyzes the possible deficiency， and on the basis of research ideas and research content of this article is designed.（2） Analysis of the traffic characteristic of expressway system in detail fromthe function， flow distribution， velocity and density distribution characteristics, aswell as analysis the principle and the basic control mode of the control system ofexpressway are analyzed in detail, provide the basis for further research.（3） Analyzes the basic characteristics of freeway traffic，according to thesummary of the existing ramp control theory，designed a fuzzy controller under trafficflow prediction，combined with time series forecasting method based on echo statenetworks for short-term traffic flow forecasting，Control model was validated usingsimulation methods.（4） This paper analyzes the relationship between the ramp and adjacentintersections，proposed ramp and adjacent intersection coordinated control systembased on the integration of resources， by setting the queue length，congestion anddelays evaluation index parameters，the control strategy results were verified byVISSIM.（5） Summarizes the full text research contents and train of thought,summarized the research achievements, put forward in the research process of thedeficiencies, prospects the future development direction of the research field.