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Spillback congestion in dynamic traffic assignment: A macroscopic flow model with time-varying bottlenecks 总被引:1,自引:0,他引:1
Guido Gentile Lorenzo Meschini Natale Papola 《Transportation Research Part B: Methodological》2007,41(10):1114-1138
In this paper, we propose a new model for the within-day Dynamic Traffic Assignment (DTA) on road networks where the simulation of queue spillovers is explicitly addressed, and a user equilibrium is expressed as a fixed-point problem in terms of arc flow temporal profiles, i.e., in the infinite dimension space of time’s functions. The model integrates spillback congestion into an existing formulation of the DTA based on continuous-time variables and implicit path enumeration, which is capable of explicitly representing the formation and dispersion of vehicle queues on road links, but allows them to exceed the arc length. The propagation of congestion among adjacent arcs will be achieved through the introduction of time-varying exit and entry capacities that limit the inflow on downstream arcs in such a way that their storage capacities are never exceeded. Determining the temporal profile of these capacity constraints requires solving a system of spatially non-separable macroscopic flow models on the supply side of the DTA based on the theory of kinematic waves, which describe the dynamic of the spillback phenomenon and yield consistent network performances for given arc flows. We also devise a numerical solution algorithm of the proposed continuous-time formulation allowing for “long time intervals” of several minutes, and give an empirical evidence of its convergence. Finally, we carry out a thorough experimentation in order to estimate the relevance of spillback modeling in the context of the DTA, compare the proposed model in terms of effectiveness with the Cell Transmission Model, and assess the efficiency of the proposed algorithm and its applicability to real instances with large networks. 相似文献
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利用极值理论和驻点分析方法,通过对沥青路面结构设计参数的分析,找出了产生"反常现象"的详细原因及其影响因素,并根据极值理论提出了"反常现象"时土基驻点弹性模量的具体求解方法。在沥青路面结构补强设计的实际工程中,这些结论为如何避免反常现象的发生提供了理论依据,并为沥青路面结构补强优化设计提供了理论依据。 相似文献
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该文以靖宇至辉南的龙岗隧道为研究载体,利用有限元方法分析隧道围岩的应力分布特征,并应用格里菲斯判据来分析围岩内裂纹扩展规律。研究表明,在硐室的周边拉应力区和应力集中程度高的区域易产生裂纹扩展。该工程中拉应力产生的部位主要在硐底中心附近,应力集中区分布于硐肩和拱角处,所以在硐底、硐肩和拱角处易产生裂纹扩展。 相似文献
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超循环理论是M·艾根等创建的一个较为完整的自组织理论,该理论运用反应循环、催化循环、催化超循环三个循环,系统诠释了生物进化无机物到生命细胞的形成过程。在系统分析思想的指导下,文中将超循环理论应用到交通影响分析阀值的研究中,提出了一种研究阀值的新方法——超循环理论法。该方法运用系统动力学及不动点理论建立模型,通过对模型的求解,确定最终阀值。该方法的运用,简化了阀值研究程序,节省了阀值分析时间,具有较强的操作性。 相似文献
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公路网的交通适应性既存在模糊性也存在随机性,但目前国内公路网交通适应性评价方法只侧重其中的某一方面,这显然是欠科学的。基于模糊理论和概率论的云理论具有同时处理模糊和随机问题的能力,并且过程简单,容易实现。研究了如何应用云理论来处理公路网交通适应性评价过程中的模糊性和随机性问题,设计了具体的评价步骤,并以湖北省恩施自治州和黑龙江省公路网为例给出了如何应用云理论进行评价的过程,评价结果表明与实际情况相吻合。与传统评价方法相比,本文提出的方法非常便于评价公路网的交通适应性,并且具有在给出评价结果的同时还能给出评价结果可信度信息的优点。 相似文献
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In this study, we examine how the spatial distribution of housing supply impacts people’s residential choices and developers’ profitability. By optimally providing housing supply in a region, developers attempt to maximize their profits; on the other hand, if residents were given a chance to decide on housing supply, what patterns of housing supply they would prefer in order to maximize their consumer surpluses. This paper studies the interplay between these two perspectives. A nested multinomial-logit choice structure that encapsulates the bid-rent process is used to capture residents’ location and travel choices simultaneously, and the resultant rents at different locations. To investigate the optimal housing supply for these two stakeholders, we conduct sensitivity analyzes to explore the impact of different housing supply patterns on total rental profit and total consumer surplus. Specifically, analytical results are derived for a simple linear network with two residential locations and one destination under homogeneous and heterogeneous value(s) of time. The results of the sensitivity analyzes indicate that segregation of housing supplies at different locations for different income classes is, surprisingly, a “preferred” outcome by residents under consumer surplus maximization, whereas creating housing supply shortages at convenient locations is a natural outcome under housing profit maximization. These results provide insights on revealing the differences and tradeoffs in performance between these two different perspectives, and on where land use regulations may be needed to balance these two objectives. 相似文献