考虑人车交互的两相位信号控制交叉口配时优化方法研究

在城市道路中,过街行人对车流运行有着很大影响。研究新交通法规实施下行人对交叉口车辆运行的影响,基于韦伯斯特信号配时方法考虑人车交互的两相位信号控制交叉口配时优化模型。模型以车流量、行人流量、车辆避让率及行人避让率为主要变量量化过街行人对交叉口信号配时的影响,通过模型分析可得新交规实施下城市不同交叉口、不同交通量条件下的交叉口信号配时优化方案。以上海市九江路-湖北路为例,应用所提出的信号配时方法进行信号配时优化,在Vissim中进行模拟,并以车辆延误、排队长度等为指标对方案进行评价。结果表明,研究提出的人车交互的两相位信号控制交叉口配时优化模型,可在其他交通条件不变的情况下有效提高交叉口运行效率。     

典型交叉口混合交通冲突分析与处理方法

本文分析了混合交通环境下机动车、自行车和行人的冲突情况 ,研究了这些冲突对交叉口通行能力的影响。提出设置左转自行车相位和自行车、行人相位提前截止等解决方案。并建立了左转自行车相位设置流量临界值的概念和自行车、行人提前截止时间的计算模型。这些理论成果可用于解决混合交通环境下机动车、自行车和行人的冲突问题。     

城市信号控制交叉口右转专用车道通行能力分析

由于受到行人及自行车的干扰,我国城市交叉口右转专用车道的服务水平受到很大影响,其通行能力的估算是混合交通流影响研究的重要内容。通过对国内外关于交叉口混合交通的研究,分析城市信号交叉口混合流影响的阻滞机理,通过对北京市数个典型交叉口的调查观测,提出基于时间分离和空间划分的右转车道通行能力计算方法。在实际观测调查的基础上,比较所提计算方法与美国道路通行能力手册(HCM2000)中计算模型所得出的不同计算值。由于合理考虑了混合交通的干扰,使时空划分方法所得计算值与实际观测情况比较接近,较好描述了右转专用车道在混合流条件下的通行能力损失。对于城市交叉口的交通设计及混合流冲突行为的研究有一定借鉴意义。     

基于交通流动态特性的交叉口复杂度模型研究

为了综合衡量城市道路交叉口空间布局形式的复杂性及交通流运行的有序性,从宏观及微观两个层面建立复杂度模型。选取冲突点及冲突概率作为影响复杂度的主要因素,应用图示法及摄影测量方法阐述冲突点的求解过程,采用统计分析及曲线拟合的方法建立冲突概率的计算模型,通过具体算例求解不同空间布局形式的交叉口在不同交通需求下的复杂度数值。结果表明:对于同一类型交叉口而言,其复杂度随流量的增加而增加;对于同一流量条件而言,不同类型的交叉口其复杂度随车道数的增加而增加。复杂度是交叉口运行状态综合性的量化指标,可应用于城市路网的规划及交叉口的安全评价中。     

城市A类平面交叉口控制新模型

城市A类平面交叉口控制新模型是在用信号管制的主干路—主干路交叉口处,入口设置直行车道、左右转弯合并车道、公交专用车道的模型。交通流按分开的时间运行,用四相位定周期配时方法,每一种控制状态对直行或转弯车辆、行人配给通行权,并合理安排这些控制状态的显示顺序。车辆进入信号控制交叉口后,要根据信号灯提供的通行相位排队等候通过。该模型在时间上使相互冲突的车流分离,消除了各向车流之间的相互干扰,提高了车辆运行的安全性和效率。     

城市道路平面交叉口规划的研究

为了合理设置城市道路交叉口,选取典型的有信号交叉口、无信号交叉口及环形交叉口,进行交叉口高峰小时的交通流特性调查,分析造成交叉口延误和影响通行能力的原因,归纳各类型交叉口的使用性,建立交叉口的通行能力计算模型,提出了交叉口规划原则.论文的研究可为已有平面交叉口改造和新建平面交叉口的规划设计提供技术支持.     

左转远引交叉口交通组织与几何参数研究

分析左转车辆对交叉口车辆运行的较大影响,研究利用左转车辆远引技术实现交叉口车辆左转的交通组织设计方法。建立了左转车辆远引交叉口中央回转开口与主交叉口距离、中央开口半径和通道宽度几何参数的计算模型和公式,经实例计算,给出了有关参数和建议值。分析表明,左转车辆远引技术可以消除交叉口处车辆的左转,从而减少了交叉口信号控制的相位数,降低了直行车辆的延误,提高了交叉口通行能力和干路车流的连续性。     

道路平面交叉口次路远引几何参数设置及通行效率研究

次要车流的左转和直行对交叉口车辆运行影响较大,特别是主路交通流量较大时尤为明显,通过次要道路车流远引的方式可以减少交叉口车辆冲突,有利于提高交叉口运行效率。分析了平面交叉口次路远引适用条件与车流组织方法,以延误最小为目标,构建了远引回转车流掉头位置、远引车辆掉头排队车道长度、远引掉头处开口长度与宽度等关键几何参数计算模型,提出了次路远引交叉口延误和通行能力等计算方法。结合实例验证了上述方法的可行性,仿真显示,在一定条件下平面交叉口次路远引可有效减少信号相位数和车辆平均延误,表明了平面交叉口次路远引的交通组织方法对优化城市道路交叉口设计有较好的应用价值。     

信号周期对道路交叉口延误和通行能力的影响研究

以典型十字信号控制交叉口为研究对象,基于工作日早高峰时段(7:00—8:00)实际调查的交通量、渠化方案、信号相位等数据,利用Synchro软件研究信号周期对交叉口通行能力和延误的影响规律.研究发现:随着信号周期的增加,在渠化方案和流量不变的情况下,交叉口的延误和通行能力也随之增加.当交叉口的通行能力或信号周期一定时,渠化方案II("左转+直右+右转")优于渠化方案I("左转+直行+右转").当渠化方案和信号周期一定时,随着右转专用车道转入直右共用车道的车辆比例增加,交叉口的通行能力降低,延误增加.研究结果可为交通管理部门决策者提供决策支持,缓解城市交通瓶颈处的拥堵.     

公交车辆停靠对信号交叉口通行能力的影响

对因公交车辆的停靠造成的信号交叉口通行能力的损失进行了详细的分析,从而更加完善了公交站点停靠对信号交叉口的影响分析理论,为合理设置公交线路及站台位置,评价公交影响及运行效益提供了理论基础与分析工具。     

Impact of Trucks on Signalized Intersection Capacity

Abstract: The most common method used for the analysis of signalized intersections in the United States is contained in the Highway Capacity Manual (HCM). In this method, the base saturation flow rate of the signalized intersection is defined in units of passenger cars per hour green per lane (pc/hg/ln). To account for the presence of large trucks in the traffic stream, the HCM includes a Passenger Car Equivalency (PCE) value. In the current edition of the HCM, a PCE value of 2.0 is applied for all large trucks, with no distinction between different sizes of trucks. The HCM also recommends a single value of 2.0 seconds for startup lost time, regardless of queue composition. Many transportation professionals have questioned the validity of the PCE value and startup lost time recommended by the HCM. They are concerned that the impact of trucks at signalized intersections is being underestimated. If this is the case, then capacity is being overestimated and intersections are not being adequately designed. The objective of this study was to identify appropriate truck PCE values and a relationship for startup lost time as a function of truck percentage in the traffic stream. To accomplish this objective, a custom simulation tool was developed based on the modified Pitt car‐following model, calibrated with field data, and applied to a comprehensive experimental design. The PCE values determined from this study are 1.8, 2.2, and 2.8 for small, medium, and large trucks, respectively. A model for estimating startup lost time based on the same small, medium, and large truck classifications was also developed.     

Increasing Signalized Intersection Capacity with Unconventional Use of Special Width Approach Lanes

Heavy traffic volume coupled with insufficient capacity due to limited space cause most of traffic congestion at urban signalized intersections. This article presents an innovative design to increase the capacity of heavily congested intersections by using the special width approach lane (SWAL), which consists of two narrow approach lanes that are dynamically utilized by either two passenger cars or a heavy vehicle (e.g., buses or trucks) depending on the composition of traffic. The impact of the SWAL on the saturation flow rate is quantified and validated, followed by an optimization model for best geometric layout and signal timing design with the presence of the SWAL. The optimization model is formulated as a mixed‐integer‐linear‐program for intersection capacity maximization which can be efficiently solved by the standard branch‐and‐bound technique. Results of extensive numerical analyses and case studies show the effectiveness of SWAL to increase intersection capacity, indicating its promising application at intersections with very limited space that prevents the addition of separate lanes.     

A Bi‐Level Model for Planning Signalized and Uninterrupted Flow Intersections in an Evacuation Network

Abstract: The problem to be addressed in this paper is the lack of an advanced model in the literature to locate the optimal set of intersections in the evacuation network for implementing uninterrupted flow and signal control strategies, respectively, which can yield the maximum evacuation operational efficiency and the best use of available budgets. An optimization model, proposed in response to such needs, contributes to addressing the following critical questions that have long challenged transportation authorities during emergency planning, namely: given the topology of an evacuation network, evacuation demand distribution, and a limited budget, (1) how many intersections should be implemented with the signals and uninterrupted flow strategies; (2) what are their most appropriate locations; and (3) how should turning restriction plans be properly designed for those uninterrupted flow intersections? The proposed model features a bi‐level framework. The upper level determines the best locations for uninterrupted flow and signalized intersections as well as the corresponding turning restriction plans by minimizing the total evacuation time, while the lower level handles routing assignments of evacuation traffic based on the stochastic user equilibrium (SUE) principle. The proposed model is solved by a genetic algorithm (GA) ‐based heuristic. Extensive analyses under various evacuation demand and budget levels have indicated that the location selection of uninterrupted flow and signalized intersections plays a key role in emergency traffic management. The proposed model substantially outperforms existing practices in prioritizing limited resources to the most appropriate control points by significantly reducing the total evacuation time (up to 39%).     

Dynamic Optimal Traffic Assignment and Signal Time Optimization Using Genetic Algorithms

Abstract:   In this article a dynamic system-optimal traffic assignment model is formulated for a congested urban road network with a number of signalized intersections. A simulation-based approach is employed for the case of multiple-origin-multiple-destination traffic flows. The artificial intelligence technique of genetic algorithms (GAs) is used to minimize the overall travel cost in the network with fixed signal timings and optimization of signal timings. The proposed method is applied to the example network and results are discussed. It is concluded that GAs allow the relaxation of many of the assumptions that may be needed to solve the problem analytically by traditional methods.     

Detection of critical road roughness sections by trend analysis and investigation of driver speed interaction

Pavement roughness (IRI—International Roughness Index values) influence the stability of traffic movements both on intercity roads and urban roads. This study is to determine the exact locations of critical pavement roughness values that affect traffic motion stability and comfort in city centre highway arteries. Roughness data with 10 m intervals were collected on a 3140 m divided road containing three consecutive signalized intersections in the city centre arterial. These data were analysed using the distance-dependent Mann-Kendall trend analysis method and checkerboard model. The sections where roughness is important were determined at a 95% confidence interval. The results will show where future pavement improvements should be prioritized for municipalities and road maintenance engineers and will form a basis for the urban road management system.     

信号交叉口车辆排队统计方法研究

信号交叉口排队控制的关键在于排队统计.以排队检测器和感应检测器为硬件基础,检测进口车辆排队状态,设计排队统计逻辑对采集的实时信息做出规整,建立排队统计方法,为信号机提供准确的路口排队信息,提高排队控制效果.应用Vissim交通仿真软件对排队统计策略进行仿真分析,结果表明,交叉口排队信息优化了配时方案,减少了绿灯损失时间、停车次数和延误,完善了智能交通控制效果.     

An Analytical Approach for Estimating the Highway Capacity Manual Signalized Intersection Delay Variability

Abstract: This article developed a generalized model incorporating three stochastic input variables in the Highway Capacity Manual (HCM) delay equation and analyzed the delay variability explicitly considering variations in key input variables including traffic volume, effective green time, and saturation flow rate. An integration method was used for calculations of mean and variance of the HCM delay. Unlike the previous Expectation Function Method, the proposed integration method can be applied for both undersaturated and oversaturated situations. The applicability of the proposed methodology was demonstrated through a hypothetical case study for a lane group at an isolated signalized intersection. The effects of stochastic variables (e.g., traffic volume, saturation flow rate, and effective green time) and correlations among these variables in the HCM delay were examined.     

信号控制交叉口进口道公共汽车停靠影响分析

本文在分析信号控制交叉口进口道公共汽车 (以下简称公交) 停靠时间特性的基础上,对国内典型的进口道公交停靠现象进行了分类与总结,并主要针对公交占用机动车外侧混合车道停靠的情况进行了定量分析,得出了公交停靠损失时间、站台位置及单位小时公交停靠车辆数等参数与交叉口交通延误、通行能力等交通效益指标变化情况的相互关系,从而为合理设置公交线路及站台位置,评价公交影响及运行效益提供了理论基础与分析工具。     

Wireless charging utility maximization and intersection control delay minimization framework for electric vehicles

This study presents the Wireless Charging Utility Maximization (WCUM) framework, which aims to maximize the utility of Wireless Charging Units (WCUs) for electric vehicle (EV) charging through the optimal WCU deployment at signalized intersections. Furthermore, the framework aims to minimize the control delay at all signalized intersections of the network. The framework consists of a two‐step optimization formulation, a dynamic traffic assignment model to calculate the user equilibrium, a traffic microsimulator to formulate the objective functions, and a global Mixed Integer Non‐Linear Programming (MINLP) optimization solver. An optimization problem is formulated for each intersection, and another for the entire network. The performance of the WCUM framework is tested using the Sioux Falls network. We perform a comparative study of 12 global MINLP solvers with a case study. Based on solution quality and computation time, we choose the Couenne solver for this framework.