安徽省公路网络可达性空间格局及其演化

以1996、2004、2010 年为时间断面, 加权平均旅行时间为指标, 探讨安徽省公路网络中节点城镇可达性空间格局及其演化规律。结果表明:1996-2010 年, 安徽省公路网络可达性总体空间格局变动不大, 其值大体以合肥地区为中心向外围呈不规则环状递增, 且空间分布具有一定的交通干道指向性。公路网络完善极大地提高了区域内节点城镇可达性, 其中第一阶段(1996-2004 年)可达性值提升较第二阶段(2004-2010 年)更为显著;可达性变化幅度与初值有关, 第一阶段可达性值变化率空间格局由“徐合高速-合芜宣高速”沿线地区和沿江地区组成的“T型”区域向周围递减, 第二阶段呈现出沿新建高速公路地区向四周递减的多极空间格局;不同地区可达性受益迥异, 江南地区可达性受益最为显著, 其次是淮北、江淮地区;随着路网的不断完善, 可达性水平由中心向外围呈圈层式优化, 可达性等值线趋于均匀、平滑, 中心城市可达性差异逐渐缩小, 可达性分布趋于均衡。

Spatial Pattern and Evolution of Road Network Accessibility in Anhui Province

Based on the road network maps in 1996, 2004, and 2010, choosing weighted average travel time as an indicator, the spatial pattern and evolution of major cities’road accessibility in Anhui Province are studied. Results are shown as follows: In the study period (1996-2010), the spatial structure of accessibility in Anhui Province shows little change; Hefei area is the center with the lowest accessibility level; the value increases from the center to the surrounding areas, and its distribution is alongside with the directions of traffic arteries. The improvement of road networks greatly increases the accessibility of major cities in the region, and the accessibility increase in the first period (1996-2004) is greater than that in the second period (2004-2010). The extent of accessibility change is related to the initial level. In the first period, the rate of the accessibility change decreases from the“T-shaped”region, covering the areas along the“Xu-He”,“He-Wu-Xuan”highway and the Yangtze River, to periphery areas. However, the second period sees a multi-core spatial pattern in which the rate of accessibility change decreases from the areas with newly constructed highways to the surrounding areas. Different areas benefit from the access to the road network differently, with Jiangnan area benefiting the most, Huaibei and Jianghuai areas the second. With the improvement of road networks, the accessibility gets optimized from a center to periphery in layered circles with the accessibility levels evenly and smoothly distributed. Among the cities, the difference of accessibility gradually narrows, and accessibility coefficient gradually reaches an equilibrium distribution.