Rainfall always has a direct impact on the travel time reliability of the highway network. Taking into account the adverse driving conditions under rain environment, such as poor visibility and low friction coefficient, the improved model of free flow speed, capacity and demand is established based on the analysis of spatial distribution pattern of rainfall. Thus, the generalized road travel time function is proposed to elaborate these factors. With user optimal equilibrium assignment formula and the series-parallel theory, the model to evaluate the travel time reliability of the road unit, path, OD pairs and network system is proposed by analyzing the network supply and demand levels. Then, the distribution of the rainfall on the highway network is simulated by the Matlab toolbox, and the model is solved with the Monte Carlo methods. Finally, a simple example illustrates the methods in the application to evaluate the travel time reliability of highway network under rain environment. The results indicate that the methods enable effectively identify the critical road sections with high sensitivity about travel time in the network.%降雨作为一种常见的气象条件,对高速公路网行程时间的稳定性有着直接的影响.本文针对雨天能见度降低、路面摩擦系数变小的特征,通过分析降雨的空间分布模式,建立了雨天路段单元自由流车速、通行能力以及公路网需求水平的修正模型,进而提出了雨天路段单元的广义行程时间函数.结合用户最优平衡分配模型,以及系统工程中的串并联理论,建立了雨天高速公路路段单元、路径、OD对和公路网的行程时间可靠度评价模型.应用Matlab工具箱模拟公路网上的降雨分布,设计了基于Monte Carlo方法的评价模型求解思路.最后以算例验证了该方法在行程时间可靠性评价中的应用.结果表明,能藉此有效地找出雨天公路网中行程时间敏感性最大的关键路段.
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