Improving The Reliability Of Subway Network Connectivity By Means Of Conventional Public Transit Under Random Attacks

In the past decade, the car ownership in China increased year by year, along with which vehicle population has been increasing, leading to more intense congestion in urban traffic. Facing the limited road resources and the seriousness of air pollution, the solution to this situation appealing to cities is rail traffic construction. Urban rail traffic has the characteristics of large capacity, quick speed, high reliability in transport time, high safety, low environment pollution and less energy and land usage etc.However, in addition to the large investment, rail traffic has its space limitations, when the urban rail traffic network suffers random attack or deliberate assault, the service performance of partial circuits and sites is greatly reduced, or even paralyzed, causing the problems that network accessibility is lowered, passengers using rail traffic are timely evacuated and they have to change travel routes, etc. Based on the background that random attacks occur in subway network, conventional public traffic is employed to integrate subway network, achieving the goal of enhancing the connection reliability of the whole public traffic network.This paper firstly introduces the network characteristic of Beijing subway network, including the basic index, feature index and the reliability index, to judge the development degree of the subway network, and determines the key nodes and key edges; secondly, according to the frequency of the random attack and deliberate attack happened in the world, random attack is chosen to be the main research background, whose destroy degree is set into three degrees and every degree is analyzed concerning the trend of passengers shift; thirdly, this paper records the situation of conventional bus traffic facilities in research region and analyzes the weaknesses of the extant conventional bus traffic network. Finally, based on the three degrees of network destruction, this paper discusses the improvements and effects and existent problems in connection reliability of extant bus traffic on randomly attacked subway network.This paper concludes that:Beijing metro network has obvious scale-free and small-world features, the research part of the network has low network connectivity and complexity, high robustness, the key node of the part is Dong-si station and the stations in 1st line; according to the difference in the degree of damage with nodes, edges and vehicle, the damage is divided into three degrees; under random attack, conventional bus traffic plays a significant role in connection reliability of subway network. However, the usual phenomena such as deficiency of routes and low frequency of bus departure make it impossible to meet the demand for passengers shift when random attacks occur in subway.