随机需求道路网络出行时间可靠性评估方法

摘要

为提高不确定路网可靠性评估的合理性,设需求服从对数正态分布,假定出行者在随机需求作用下能够达到确定性用户均衡,运用路径算法获得流量,根据BPR(bureau of public roads)型路段特性函数以及对数正态分布的概率特性,给出了路径出行时间的随机分布,以此为基础建立了路径及OD对出行时间可靠性评估模型.用数值算例验证了评估方法的可行性,分析结果表明该方法能够合理评价需求及其波动程度、路径之间的相关程度对出行时间可靠性的影响.%A model for evaluation of travel time reliability of routes and OD pairs was proposed. In the model, it is assumed that the deterministic user equilibrium ( UE) is reachable under stochastic demands with a log-normal distribution. Route traffic flows are calculated with a route-based solution algorithm for UE, and the distributions of route travel times are determined using the BPR ( bureau of public roads) type link impedance function based on the log-normal distribution. The feasibility of the proposed method was validated with a numerical example, showing that it was applicable to investigation on the influences of demands and their variations, and correlation among routes on travel time reliability.