城市是人类创造的最大物理社会系统,其功能丰富,元素繁多,关系密切,结构复杂,影响巨大。然而,城市在发展过程中,规划往往比较软弱,跟不上需求的变化。随着城市人口的快速增长和人们对生活追求的更多、更快、更方便,公交、铁路、飞机、汽车、地铁日益增多,出现了大规模生产、物流运输、废物排放以及各种功能的服务设施,如超市、银行、排污、通讯、数据中心、保健、养老等。各种系统日益庞大,越来越复杂,城市出现了交通拥 City is the largest physical and social system created by mankind. Its function is rich, its elements are numerous, its relations are close, its structure is complex and its influence is huge. However, in the process of urban development, the planning is often weak and can not keep up with the changes in demand. With the rapid growth of urban population and people’s pursuit of life more, faster and more convenient, mass transit of buses, railways, airplanes, automobiles and subways has brought about mass production, logistics and transportation, waste discharge and various functions Service facilities such as supermarkets, banks, sewerage, telecommunications, data centers, healthcare, retirement and more. Increasing variety of systems, more and more complex, the city appeared traffic