The Economics of Rush-Hour Traffic Dynamics: Beyond the Bottleneck Model

交通拥堵是现代生活的祸害之一。然而，令人惊讶的是，直到最近，关于城市街道交通拥堵的系统数据收集得很少(与高速公路形成对比)，这阻碍了为缓解市中心交通拥堵而制定明智的政策。最近收集的数据产生了一个重要的发现：在严重拥堵的条件下，城市街道系统的性能急剧恶化--比高速公路更严重。这有两个重要的政策含义。首先，重要的是实施将交通拥堵扼杀在萌芽状态的政策。其次，市中心的拥堵收费产生了比之前认为的更大的社会效益。这项研究工作开发了城市街道高峰时段交通拥堵的模型，解释了这一发现，并将其应用于分析替代缓解拥堵政策的效果。这项研究将支持一名应用数学博士生，并鼓励其他此类学生将他们的技术技能应用于市中心交通拥堵的研究。四分之一个世纪以来，瓶颈模型一直是研究高峰时段交通动力学的主要模型。虽然它产生了许多见解，但它有一个严重的缺陷--它假设交通流量在严重拥堵的情况下保持不变。最近对市中心MFD宏观基本图的实证研究表明，相反，在严重拥堵的情况下，流量会急剧下降。以前的工作已经开发了一个高峰时段交通动力学模型，该模型适应了经验MFD--市中心交通拥堵的各向同性模型。不幸的是，事实证明，该模型在分析和数值上都难以处理。该项目旨在开发易于处理的算法来求解该模型，并在其解析解方面取得进展。这些工具将导致对旨在缓解市中心交通拥堵的政策进行更准确的分析，不仅包括拥堵收费，还包括停车和拥堵管理政策。

Traffic congestion is one of the banes of modern life. Surprisingly, however, until recently very little systematic data had been collected on traffic congestion on urban streets (in contrast to freeways), which has hampered the development of well-informed policies for the alleviation of downtown traffic congestion. The recently collected data have generated an important finding: the performance of the urban street system deteriorates sharply under heavily congested conditions -- more sharply than freeways. This has two important policy implications. First, it is important to implement policies that nip traffic jams in the bud. Second, congestion pricing in downtown areas generates even larger social benefits than previously believed. This research effort develops models of rush-hour traffic congestion on urban streets that account for this finding and applies them to analyze the effects of alternative congestion-relief policies. The research will support one Ph.D. student in applied mathematics, and encourage other such students to apply their technical skills to the study of downtown traffic congestion. The bottleneck model has been the workhorse model for the study of rush-hour traffic dynamics for a quarter of a century. While it has generated many insights, it has a serious flaw -- it assumes that traffic flow remains constant under heavily congested conditions. Recent empirical study of the MFD -- macroscopic fundamental diagram -- in downtown areas has shown, to the contrary, that flow falls sharply under heavily congested conditions. Previous work has developed a model of rush-hour traffic dynamics that accommodates the empirical MFD -- the isotropic model of downtown traffic congestion. Unfortunately the model has proven analytically and numerically intractable. The project aims to develop tractable algorithms to solve the model and also make progress in its analytical solution. These tools will lead to more accurate analysis of policies aimed at alleviating downtown traffic congestion, including not only congestion pricing but also parking and congestion management policies.