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51.
Yiguang XuanCarlos F. Daganzo Michael J. Cassidy 《Transportation Research Part B: Methodological》2011,45(5):769-781
A separate turn phase is often used on the approach leg to an intersections with heavy left turns. This wastes capacity on the approach because some of its lanes cannot discharge during its green phases. The paper shows that the problem can be eliminated by reorganizing traffic on all the lanes upstream of an intersection using a mid-block pre-signal. If drivers behave deterministically, the capacity that can be achieved is the same as if there were no left turns. However, if the reorganization is too drastic, it may be counterintuitive to drivers. This can be remedied by reorganizing traffic on just some of the available lanes. It is shown that such partial reorganization still increases capacity significantly, even if drivers behave randomly and only one lane is reorganized. The paper shows how to optimize the design of a pre-signal system for a generic intersection. It also identifies both, the potential benefits of the proposed system for a broad class of intersections, and the domain of application where the benefits are most significant. 相似文献
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Recently connected vehicle (CV) technology has received significant attention thanks to active pilot deployments supported by the US Department of Transportation (USDOT). At signalized intersections, CVs may serve as mobile sensors, providing opportunities of reducing dependencies on conventional vehicle detectors for signal operation. However, most of the existing studies mainly focus on scenarios that penetration rates of CVs reach certain level, e.g., 25%, which may not be feasible in the near future. How to utilize data from a small number of CVs to improve traffic signal operation remains an open question. In this work, we develop an approach to estimate traffic volume, a key input to many signal optimization algorithms, using GPS trajectory data from CV or navigation devices under low market penetration rates. To estimate traffic volumes, we model vehicle arrivals at signalized intersections as a time-dependent Poisson process, which can account for signal coordination. The estimation problem is formulated as a maximum likelihood problem given multiple observed trajectories from CVs approaching to the intersection. An expectation maximization (EM) procedure is derived to solve the estimation problem. Two case studies were conducted to validate our estimation algorithm. One uses the CV data from the Safety Pilot Model Deployment (SPMD) project, in which around 2800 CVs were deployed in the City of Ann Arbor, MI. The other uses vehicle trajectory data from users of a commercial navigation service in China. Mean absolute percentage error (MAPE) of the estimation is found to be 9–12%, based on benchmark data manually collected and data from loop detectors. Considering the existing scale of CV deployments, the proposed approach could be of significant help to traffic management agencies for evaluating and operating traffic signals, paving the way of using CVs for detector-free signal operation in the future. 相似文献
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交叉口协调感应信号控制 总被引:1,自引:0,他引:1
介绍了传统的感应控制方法,着重对协调感应信号控制的基本原理,控制过程等进行了分析,并提出了解决问题的方法。分析了定时信号控制和感应信号控制的优缺点,对感应信号控制的进一步研究提出了几点看法。 相似文献
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汽车前照灯配光性能测试方法的研究 总被引:3,自引:0,他引:3
着重阐述了前照灯近光配光性能测试中的各测试点及区域的含义、测试方法以及误差分析。提出了提高测试速度和精度的方法,还介绍了国家汽车质量监督检查中心研制的激光灯具全自动照准仪和计算机多功能配光自动测试软件及其应用。 相似文献
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单点交叉口信号实时配时模型及蚂蚁算法 总被引:2,自引:2,他引:2
以延误时间、停车次数和通行能力作为性能指标,各性能指标的加权系数随交通需求的不同而变化。提出交叉口实时配时,采用一种新型随机搜索思想——蚂蚁优化算法来求解此模型的非线形问题。仿真试验表明,所得结果优于经典方法,降低了交叉口的总延误时间和停车次数,提高了通行能力。 相似文献
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