中国高速公路网的可达性格局及演化

在全国尺度上评价1988~2030年中国高速公路可达性的空间格局及演化。基于交通旅行时间和最短时间路径的可达性模型设计,刻画了中国高速公路网的扩张过程,评价各时段中国高速公路网的通达性及演变,包括连通城镇、交通时间和时间区位系数等,分析各地区可达性的空间差异及变化特征,以及各时段内可达性的变化差异,重点识别可达性与区位受损和收益的突出区域;结合人口和经济等属性指标,评价各城市的综合发展潜能及变化。研究发现,高速公路建设拉近了边缘地区与核心地区的时间距离,西部地区的交通条件得到了很大改善,但并没有改变各城市的区位优劣水平,而且导致城市间发展潜力的差距更加不平衡。

Spatial Pattern of Expressway Network Accessibility and Evolution in China

This article aims to examine how the size, connectivity and accessibility of the expressway network have evolved over time on a national scale and further influence the developing potential for a region during the past 25 years and future 15 years. Travel time and the shortest time path model were applied for this purpose. We describe the growth of the expressway network in China and analyze the development features, and evaluate the evolution of expressway network accessibility in each period including connectivity, travel time and location coefficient, and comparatively analyze their differences over time and space. In particular, we analyze the effect of expressways on spatial accessibility and location conditions, and identify which developments are likely to improve or detract from accessibility and location conditions. Furthermore, the composite developing potential for cities is evaluated by considering the population and regional gross domestic product to investigate the influence of expressways on regional development, and their changes before and after expressway construction is analyzed. The results show that the expressway construction has produced the obvious spatio-temporal convergence by reducing the travel time among the cities and brought the peripheral regions closer to the central regions and greatly improved the transport conditions in the western China which produce a continuously shrinking China. The accessibility of cities shows a spatial pattern of core-peripheral concentric circle configuration, and the Huanghe-Huaihe River Plain, the Guanzhong Plain, the middle and lower reaches of the Changjiang River have been the regions with the best accessibility but the worst conditions of accessibility are recorded in the northwestern and northeastern margins in China. The expressway has produced interference on the original accessibility with a certainly steady status established by traditional highways. In the early period, with the initially continuous construction of expressway, this interference was likely to be more obvious. But with the fully interconnected networking of expressway, it setbacks rapidly and the accessibility difference among the nodes also returns to original level, because expressway network becomes a new transport infrastructure increasingly to replace the existing highway. However, the expressways not only could not change the superior/poor level of locational condition for a city in the whole China but also increased the imbalances in development opportunities among cities.