Study On Characteristics And Stability Of Urban Multi-modal Public Transit Complex Network

Urban public transit has the advantages of large capacity,high efficiency and low energy consumption,and plays an important role in the urban transportation system.At present,a single mode of public transit development can no longer meet the growing traffic demands of urban residents,and the coordinated development of multi-mode public transit such as metro,bus and taxis has become an inevitable trend.Based on the complex network theory,this paper takes the public transit in Beijing as the research object,and establishes a multi-mode coupled public transit complex network for three modes: metro,bus and taxi.And the stability of the multi-modal network in the face of external disturbance is analyzed in detail,aiming to do an exploratory study on the construction and analysis method of the multi-modal complex network with taxis.Firstly,the L-space method is used to construct the metro network and bus network respectively,and an improved spatial coupling node identification method based on geographic information is proposed.The feature index of interlayer degree and interlayer clustering coefficient are extended for the double-layer network.Then,the double-layer network is converted into a compound network,and the Beijing city is taken as an example to analyze the impact of the combination of metro and bus on the overall performance of the network.The results show that the Beijing compound complex network and bus network are all scale-free networks.The average degree and clustering coefficient of the compound network are higher than those of the single-mode network,while the diameter and average path length are lower than the latter,indicating that the compound network presents a better role than the single-mode network.Then,the P-space method is used to construct a single-mode passenger flow weighted network of taxis in Beijing,and it is found that it is a small-world network with high clustering coefficient and short path length.From the perspectives of competitiveness and synergy,the coupling relationship between taxi and public transit stations is analyzed,the metro-bus-taxi public transit network is constructed,and the correlation characteristics between taxi,metro,and bus network layers are discussed.It is found that the setting rate of public transit stations near the hotspot area is higher than that of the ordinary area,and the average degree of the metro stations coupled with the nodes of the hotspot area is higher than that of the ordinary area,indicating the consistency of the supply of taxis and metro.Finally,based on the metro-bus-taxi public transit network model and the coupling effect between different modes,numerical simulation of the static stability of Beijing’s multi-modal public transit network is carried out.By setting three attack modes: degree priority deliberate attack,betweenness priority deliberate attack and random attack,and considering under the dual-mode coupling effect,explore the stability of metro network,bus network.The simulation results show that the three networks are more stable when attacked randomly than when attacked deliberately,and the degree-priority deliberate attack is more destructive to the metro network and bus network.The coupling effect between different modes will have an important impact on the network stability.The more coupled modes,the greater the impact,and the static stability of the network will be significantly improved.This research can provide scientific guidance for the daily maintenance and emergency dispatch of urban public transit system.