The Road Network Partition And Fuzzy Switching Perimeter Control Of Traffic Flow Based On MFD

With the growthing of population,the gradual progressing of urbanization,traffic in large or medium-sized cities are becoming more and more congested.In order to alleviate the negative impact of congestion,The road network is partitioned based on MFD,and then control strategies are applied to the border junctions for leading vehicles in jammed areas to unjammed ones,thus easing the serious congestion.Firstly,the data used in this paper is derived from the actual data collected from the floating vehicles in Beijing.We pre-process the floating vehicle data such as screening,removing invalid or defect,complementing sample data,so that it can turn out to be more effectively reflect real conditions.At the same time,Vissim is used to establish WangJing,and ErHuan road network,which is ready for the implement of the control schme.Secondly,the basic characteristics of complex network and actual topology of urban traffic network are taken into fully consideration,therefore,an effective assessment method of network intersection’s importance is put forward,which displayed by importance order of the whole road network.Thirdly,the existence feature of MFD is analysed,and laterly the road network area is divided into different subregions.After that we continue the researching of subregions’ macroscopic feature,including the homogeneity,scatter,hysteresis or other features.Lastly,an effective perimeter control scheme among regions are designed,which switch control conduction between the fuzzy timing controller and fix timing controller based on changes about queue length of the road network system and the assessment results of network intersection’s importance on the boundary nodes.At the same time,two different road networks are established,one in Matlab platform,and the other in Vissim platform.Laterly,the simulation is proceeded respectly with the fix timing and dynamic timing control strategy in these two platforms,and then the variations generated in the above two platforms are analyzed in detail.Simulation results show that fuzzy switching boundary control scheme designed in the paper can evacuate traffic from the more severely congested subarea to the uncongested one when traffic flow increases,thus achieving the purpose of alleviating congestion in the urban road network.