长江干线过江公路发展过程及其区域连通能力评价

Development of cross the Yangtze River highways and their regional connectivity evaluation

过江通道是打破自然阻隔、连通长江南北的重要交通基础设施,对推动跨江融合、支撑长江经济带发展和实现全国南北要素流动具有重要意义。本文梳理了中国长江干线过江通道的发展过程,并采用时间可达性和中介中心性对过江公路的区域连通能力进行了评价。研究表明:(1)根据数量、类型和社会经济发展背景,长江干线过江通道的建设过程可分为起步攻坚阶段(1957—1995年)、提速扩张阶段(1996—2010年)和多功能拓展阶段(2011年至今),至2021年6月,上中下游过江通道比例达54.7∶23.4∶21.9,从经济规模和常住人口来看,长江下游过江通道密度远低于上中游地区;(2)长江经济带平均公路过江时间由1980年的19.73 h下降到2020年的6.09 h,可达性显著提升,且上、中、下游过江时间成本差距不断缩小;(3)长江南北两岸地市间跨江连通水平提升显著,过江最短路径由高度依赖于若干过江公路发展为多条过江公路共同分担,高中介中心性过江公路主要布局在长江中下游地区,而上游地区过江公路连通能力普遍偏弱。

Cross the Yangtze River passages are of great significance in promoting integration of metropolitans,supporting the development of the Yangtze River Economic Belt and realizing the flow of elements between the north and the south of China.This paper sorts out the development of cross the Yangtze River passages on the Yangtze River mainline,and evaluates the regional connectivity of cross the Yangtze River highways using accessibility and weighted betweenness centrality.The study shows that:1)according to the quantity,type and socio-economic development background,the construction process of passages can be divided into the initial stage(1957—1995),the speedup expansion stage(1996—2010)and the multi-functional expansion stage(2011—).By June 2021,the ratio of passages in the upper,middle and lower the Yangtze River reaches is 54.7∶23.4∶21.9,while in terms of economic scale and resident population,the density of passages in the lower the Yangtze River reaches is much lower than that in the upper and middle reaches.2)The accessibility of cross the Yangtze River highways has been significantly improved from 19.73 h to 6.09 h,and the time cost gap between the upper,middle and lower the Yangtze River reaches is narrowing;3)The level of connectivity is substantially strengthened.The shortest path across the Yangtze River changes from highly dependent on several highways to multiple sharing.The high betweenness centrality highways are mainly located in the middle and lower reaches of the Yangtze River,while the connectivity of highways in the upper reaches is generally weak.