Abstract: Rail transit is the backbone of urban passenger transport system, and the accessibility is an important index for evaluating the rationality of public transport. The objective and accurate evaluation of rail transit accessibility plays an important role in decisionmaking support for railtoconventional public transfer adjustment and land use planning around rail stations.By summarizing the traditional concept of accessibility and combining with the characteristics of rail transit system, the accessibility of rail transit was defined.Considering the convenience of rail transit and conventional public transit, and the convenience of interchange between rail transit stations, a model for calculating the accessibility of rail transit was established. With the help of ArcGIS, TransCAD and other tools, taking Beijing rail transit as an example, the accessibility distribution of Beijing rail transit was calculated, and the changes of the accessibility of the rail system before and after the opening of the middle section of Beijing Metro Line 14 were compared and analyzed.The result shows that the proposed method can calculate the rail transit accessibility objectively and accurately, which can be well applied in the accessibility evaluation of rail transit.

Key words: traffic and transportation engineering, urban traffic, rail transit, accessibility, bus transfer, line transfer, GIS

摘要： 轨道交通是城市客运系统的骨干，可达性是公共交通合理性评价的重要指标，客观准确评价轨道交通可达性，对轨道常规公交换乘衔接调整、轨道站点周边用地规划等均起到重要的决策支撑作用。通过对传统可达性概念的总结，结合轨道交通系统自身特点，对轨道交通可达性进行了定义。从轨道交通与常规公交换乘便利性和轨道交通自身站点间通达便利性考虑，建立了轨道交通可达性计算模型。借助ArcGIS、TransCAD等工具，以北京市轨道交通为例，计算了北京市轨道交通可达性分布状况，对比分析了北京地铁14号线中段开通前后轨道系统可达性的变化状况。结果表明，该方法能够客观准确地计算轨道交通可达性值，可以很好地应用在轨道交通可达性评价中。

关键词: 交通运输工程, 城市交通, 轨道交通, 可达性, 公交接驳, 线路换乘, 地理信息系统