Abstract: The fluctuation of travel time is a key index of transportation network reliability. The fluctuation structure of travel time includes the mutability and persistence. The structural breaks are detected to identify the mutability of the travel time fluctuation based on the ICSS method. The structural breaks are substituted into GARCH model as dummy variables to construct the fluctuation model taking mutability into consideration and analyze the fluctuation structure of travel time. Taking the floating car data of the express ways in Shanghai as a case, the empirical analysis shows that the mutations of travel time fluctuation structure lead to the persistence of fluctuation.

Key words: travel time, fluctuation structure, ICSS method, mutability, persistence

摘要： 行程时间波动性是反映道路交通网络可靠性的重要指标，行程时间的波动结构包括突变性与持续性两部分。利用迭代累积平方和算法对行程时间波动的结构性变点进行检测，对行程时间波动的突变性进行辨识。将结构性变点以虚拟变量的形式引入GARCH模型，建立考虑行程时间波动突变性的波动模型，对行程时间的波动结构进行分析。以上海市快速路系统的浮动车数据为例进行实证分析，表明行程时间波动结构的突变导致了波动的持续性。

关键词: 行程时间, 波动结构, 迭代累积平方和方法, 持续性, 突变性