Evaluation with Traffic Assignment Under Demand Uncertainty
Evaluation with Traffic Assignment Under Demand Uncertainty
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DOI：
10.3141/1771-09
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发表时间：
2001
影响因子：
1.7
通讯作者：
S. Waller;J. Schofer;A. Ziliaskopoulos
中科院分区：
文献类型：
--
作者：
S. Waller;J. Schofer;A. Ziliaskopoulos
需求的不确定性的影响，网络改善的评估时，使用交通分配的地址。理论结果表明，交通系统的性能的期望值不一定等于系统在期望值的需求，因此，期望的需求不能被用来忽略需求预测的方差。使用预期需求往往会高估网络的性能，并可能导致错误的改进选择。探讨了处理这一问题的其他可能性，包括一种使需求膨胀的方法。这不仅在选择具有较低预期总系统旅行时间的改进方面，而且在与此措施相关联的方差方面也显著减少。需求膨胀应该在预算确定之后发生，这样由通货膨胀产生的决定就不会要求建造更多的基础设施，而是要求选择不同的改进措施。此外，数值例子表明，有一个显着的概率，确定性的交通分配程序将不正确的排名改善政策。这对基于此程序的决策构成严重关切，因此讨论了解决该问题的潜在措施。
The impact of demand uncertainty on the evaluation of network improvements when using traffic assignment is addressed. Theoretical results indicate that the expected value of the performance of the traffic system is not necessarily equivalent to the performance of the system at the expected value of demand, and therefore the expected demand cannot be used with disregard of the variance in demand forecasts. Using expected demand tends to overestimate performance of the network and could lead to erroneous choice of improvements. Alternative possibilities for dealing with this problem are explored, including an approach in which the demand is inflated. This yield benefits not only in terms of selecting improvements with lower expected total system travel time but also significant reductions in the variance associated with this measure. Demand inflation should take place after a budget has been set, so that decisions resulting from inflation do not dictate that more infrastructure be built but that different improvements be selected. Furthermore, numerical examples indicate that there is a significant probability that the deterministic traffic assignment procedure will incorrectly rank improvement policies. This poses a serious concern for decisions based on this procedure, so potential actions are discussed to address the problem.