通过放松不同路段状态完全相互独立这一假设,在分析路段失效影响因素过程中摒弃常用的故障树分析法,建立路段相关、多状态条件下路网行程时间可靠性的计算方法。该方法首先确定网络最有可能发生的状态及其发生概率,计算状态空间对应的路段、路径行程时间可靠度,最后获得路段相关、多状态路网行程时间可靠度指标值。该方法的计算结果与假设路段交通状态互相独立的计算结果作比较,其结果表明,对于路网行程时间可靠度计算,相关性假设比独立性假设更为准确,路段关联失效假设,更能提高行程时间发布可信度。
By using the relaxing assumption that links the traffic states in a road network are statistically independent and abandoning the Fault Tree Analysis (FTA), a methodology was presented to compute travel time reliability in road networks with dependent link failures and multiple states. The methodology first decides the most possible traffic states in a road network and the corresponding probabilities, then calculates the travel time reliability in the link and the path corresponding to different states, and finally obtain the measurement value of travel time reliability in road networks with dependent link failures and multiple states. Comparison was made for the results from both independency and dependency assumptions, which indicates the dependency assumption would be more accurate on travel time reliability calculations, and more effective in improving the degree of belief for travel time.