新的随机高速公路通行能力估计方法及为何乘积限法不适用
New stochastic highway capacity estimation method and why product limit method is unsuitable
AI总结：
本文指出PLM和MLE因交通流测量不具备“老化”历史而不适用于随机通行能力估计，提出基于失效累积频率拟合的新方法，并通过案例研究验证其对通行能力估计的有效性。
摘要：
Kaplan-Meier估计（通常称为乘积限法（PLM））以及一般的最大似然估计（MLE）方法，常被引用为随机高速公路通行能力估计的手段。本文讨论了它们在此类应用中的不适用性，因为交通流的特性不满足使用这些方法的假设。它们假设被观测对象具有一段经历过的历史且未发生失效。然而，由于其本质，每次交通流测量都表现为一个独立的对象，并未经历所有较低的强度水平（未“老化”）。本文提出了一种替代方法。该方法拟合相对于导致失效的交通流强度的失效累积频率，而不是直接估计通行能力的潜在概率分布。文中提供了新方法对数据量和删失率的准确性与敏感性分析，并与PLM进行了比较。结果证明了PLM和一般MLE方法的不适用性。随后，新方法被用于一个案例研究，比较了安装和未安装交通流速度协调系统的工作区通行能力。结果证实了协调系统对通行能力的积极影响。
英文摘要：
Kaplan-Meier estimate, commonly known as product limit method (PLM), and maximum likelihood estimate (MLE) methods in general are often cited as means of stochastic highway capacity estimation. This article discusses their unsuitability for such application as properties of traffic flow do not meet the assumptions for use of the methods. They assume the observed subject has a history which it went through and did not fail. However, due to its nature, each traffic flow measurement behaves as a separate subject which did not go through all the lower levels of intensity (did not "age"). An alternative method is proposed. It fits the resulting cumulative frequency of breakdowns with respect to the traffic flow intensity leading to the breakdown instead of directly estimating the underlying probability distribution of capacity. Analyses of accuracy and sensitivity to data quantity and censoring rate of the new method are provided along with comparison to the PLM. The results prove unsuitability of the PLM and MLE methods in general. The new method is then used in a case study which compares capacity of a work-zone with and without a traffic flow speed harmonisation system installed. The results confirm positive effect of harmonisation on capacity.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
