Abstract: For city bus travellers, at a given start and end point and starting time travel case, alternative path set based online shortest time-consuming bus transfer method is proposed. It uses bidirectional offline preprocessing stage breadth-
first search method to get the point on the path between a static set of candidate; then combining with real-time bus arrival time prediction data or grid spacing of bus operators and other static data, it does the shortest time-consuming evaluation, to choose the shortest time-consuming path online. The method is applied to Shenyang transit network scenarios（simulation of bus arrival time prediction data generation）, and embedded in Shenyang City bus travel query system. The results show its usefulness.

Key words: bidirectional breadth-first search, shortest time consuming, bus transfer

摘要： 面向城市公交出行者，在给定出行起讫点及起始时间的情况下，提出一种基于备选路径集的在线最短耗时公交换乘方法：在预处理阶段离线地运用双向广度优先搜索方法得到点对之间的静态备选路径集；结合实时公交到站时间预测数据或发车间隔等静态的公交运营数据，进行最短耗时评估，在线地从中选择耗时最短的路径。将该方法运用于沈阳公交路网案例中（公交到站时间预测数据仿真生成），并嵌入沈阳市公交出行查询系统，结果表明了其实用性。

关键词: 双向广度优先搜索, 最短耗时, 公交换乘