In order to evaluate and integrate travel time reliability and capacity reliability of a road network subjected to ice and snowfall conditions,the conceptions of travel time reliability and capacity reliability were d...In order to evaluate and integrate travel time reliability and capacity reliability of a road network subjected to ice and snowfall conditions,the conceptions of travel time reliability and capacity reliability were defined under special conditions.The link travel time model(ice and snowfall based-bureau public road,ISB-BPR) and the path choice decision model(elastic demand user equilibrium,EDUE) were proposed.The integrated reliability was defined and the model was set up.Monte Carlo simulation was used to calculate the model and a numerical example was provided to demonstrate the application of the model and efficiency of the solution algorithm.The results show that the intensity of ice and snowfall,the traffic demand and supply,and the requirements for level of service(LOS) have great influence on the reliability of a road network.For example,the reliability drops from 65% to 5% when the traffic demand increases by 30%.The comprehensive performance index may be used for network planning,design and maintenance.展开更多
为研究冰雪条件下城市路网容量可靠性,采用路段行程时间可靠性及容量为约束条件进行研究.定义了冰雪条件下的路网容量可靠性概念,以BPR(Bureau of Public Roads)函数为基础,通过引入自由行程时间及通行能力修正函数,建立了适用于冰雪条...为研究冰雪条件下城市路网容量可靠性,采用路段行程时间可靠性及容量为约束条件进行研究.定义了冰雪条件下的路网容量可靠性概念,以BPR(Bureau of Public Roads)函数为基础,通过引入自由行程时间及通行能力修正函数,建立了适用于冰雪条件的ISB-BPR(Ice and Snowfall Based-Bureau of Public Roads)函数,并以路段容量和遵循ISB-BPR函数的行程时间可靠性作为约束条件构建了上层规划,以符合冰雪条件出行特征的弹性需求分配模型作为下层规划,提出了适用于冰雪条件的双层规划模型.根据模型反映的路径选择行为特点,设计了灵敏度分析法求解交通量分配模型,以Monte Carlo仿真算法求解路网容量可靠性.并给出1简单算例,计算结果表明:冰雪强度及交通供需对冰雪条件下路网容量可靠性有很大影响.该模型能够用于评估冰雪条件下的路网性能,并为路网规划、设计、维护提供依据.展开更多
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...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.展开更多
基金Project(E200940) supported by the Natural Science Foundation of Heilongjiang Province, ChinaProject(2009GC20008020) supported by the Technology Research and Development Program of Shandong Province, China
文摘In order to evaluate and integrate travel time reliability and capacity reliability of a road network subjected to ice and snowfall conditions,the conceptions of travel time reliability and capacity reliability were defined under special conditions.The link travel time model(ice and snowfall based-bureau public road,ISB-BPR) and the path choice decision model(elastic demand user equilibrium,EDUE) were proposed.The integrated reliability was defined and the model was set up.Monte Carlo simulation was used to calculate the model and a numerical example was provided to demonstrate the application of the model and efficiency of the solution algorithm.The results show that the intensity of ice and snowfall,the traffic demand and supply,and the requirements for level of service(LOS) have great influence on the reliability of a road network.For example,the reliability drops from 65% to 5% when the traffic demand increases by 30%.The comprehensive performance index may be used for network planning,design and maintenance.
文摘为研究冰雪条件下城市路网容量可靠性,采用路段行程时间可靠性及容量为约束条件进行研究.定义了冰雪条件下的路网容量可靠性概念,以BPR(Bureau of Public Roads)函数为基础,通过引入自由行程时间及通行能力修正函数,建立了适用于冰雪条件的ISB-BPR(Ice and Snowfall Based-Bureau of Public Roads)函数,并以路段容量和遵循ISB-BPR函数的行程时间可靠性作为约束条件构建了上层规划,以符合冰雪条件出行特征的弹性需求分配模型作为下层规划,提出了适用于冰雪条件的双层规划模型.根据模型反映的路径选择行为特点,设计了灵敏度分析法求解交通量分配模型,以Monte Carlo仿真算法求解路网容量可靠性.并给出1简单算例,计算结果表明:冰雪强度及交通供需对冰雪条件下路网容量可靠性有很大影响.该模型能够用于评估冰雪条件下的路网性能,并为路网规划、设计、维护提供依据.
文摘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.
