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路网容量可靠性是评价路网综合性能的重要指标之一，已越来越受到路网规划者和交通管理者的重视，而现有评价方法大多在确定路网最大容量过程中并没有综合考虑服务水平的约束。本文为在路网容量可靠性评价中更好地体现出行者及管理者对服务水平的要求，新建了基于服务水平约束的路网容量可靠性双层规划模型，以行程时间增量系数和饱和度系数为约束构建上层规划，结合用户路径选择行为的特点，选用SUE(随机用户平衡)分配模型作为下层规划。采用遗传算法和Monte Carlo 仿真相结合的方法求解容量可靠性模型。并给出了算例.计算结果表明,该模型能够较好地体现不同服务水平要求下的路网容量可靠性，并为城市路网规划、管理及路网性能的改善提供依据。

Assessment of Road Network Capacity Reliability Based on the Constraints of Link LOS

As one of the most important indexes of road network performance, the capacity reliability is considerably emphasized by the road network planners and managers. Most of the existing evaluation methods in determining the road network maximum capacity pay no attention to the subjections of level of service (LOS). To reflect the LOS demand of travelers and managers in estimating the road network capacity reliability, the bi-level programming model was proposed based on the subjection of LOS. The threshold of increased travel time and saturation as subjections are proposed in the upper programming model. The stochastic user equilibrium (SUE) is set up in the lower programming model to follow the characteristics of route choice. The paper proposes an assessment methodology, which integrates genetic algorithm and Monte Carlo simulation methods to evaluate the capacity reliability. A numerical example is provided to illustrate the practicality of the proposed model under different LOS requirements. This model can effectively provide grounds for road network planning, managment, and improvement of road network performance.