基于改进两步移动搜索法的轨道交通接驳可达性分析

研究城市轨道交通接驳可达性对提升轨道交通服务水平具有重要意义。本文从居民出发地角度，运用基于距离衰减的改进两步移动搜索法，计算并对比分析从居民出发地分别采取步行、 共享单车和公交这3种接驳方式到达轨道交通站点的接驳可达性。以成都三环外地铁2号线和6号线沿线区域为例，运用ArcGIS工具分析区域居民出发地的可达性空间分布差异和不同接驳方式的可达性差异，并结合人口分布梳理轨道交通出行重点区域，挖掘出行盲区。计算结果表明：越靠近轨道交通站和越靠近城市中心的区域，3种接驳方式的平均可达性越高；总体上，步行接驳可达性最小，空间分布差异最明显；步行、共享单车和公交接驳可达性高的区域分别集中在轨道站 0.8，1.5，3.0 km服务半径范围内；公交沿线接驳可达性高于非沿线接驳可达性；通过对比可达性和人口空间分布，有效识别区域轨道交通出行的重点盲区、次要盲区、一般盲区和隐性盲区。

Accessibility to Urban Rail Transit Based on Enhanced Two-step Floating Catchment Area Method

The research on the accessibility to urban rail transit is very significant to elevate the service level of rail transit. From the perspective of departure locations, this study calculates and analyzes the accessibility to rail transit stations by three connection modes (walking, shared bicycle, and bus) by using the enhanced two-step floating catchment area method (E2SFCA) based on a distance decay function. Also, taking the areas along Metro Line 2 and Line 6 outside the Third Ring Road in Chengdu as an example, the accessibility differences in spatial locations and the accessibility differences caused by different modes are analyzed by ArcGIS. By comparing the accessibility and the population distribution, the key areas of rail transit travel are sorted out, and the inaccessible areas are found. The results show that the areas that are much closer to the rail transit station and the city center have higher average accessibility of the three connection modes. The accessibility by walking is the smallest in general, and the accessibility difference in spatial distribution is the most obvious. Moreover, the areas with high accessibility are within 0.8, 1.5, and 3.0 km of rail transit stations, for walking, shared bicycle, and bus, respectively, and the accessibility along bus lines is higher than that not. Finally, the different levels of inaccessible areas by rail transit are identified by comparing the accessibility and population spatial distribution.