连续流交叉口左转非机动车优化设计方法

为了提升连续流交叉口的通行能力,消除其主信号处左转非机动车与直行机动车的冲突,提出了一种左转非机动车优化设计方法.优化模型以机动车通过量最大为优化目标,考虑了信号相位相序、周期时长、绿灯时长等约束条件,建立线性规划优化模型.通过案例和敏感性分析,验证了该设计方法的优化效益.研究结果表明,该方法不仅能在高流量情况下显著提升交叉口通行能力,使得原本处于过饱和状态的交叉口变为不饱和,而且在高流量或低流量情况下,都有助于减少交叉口延误.进一步发现,左转非机动车流量每增加100辆/h或直行机动车流量比例每增加1.5%(直行机动车流量比例大于40%),优化设计对机动车最大通过量的提升比例增加4.5%.     

对称十字交叉口竖向设计方法——整体法研究

文章针对传统交叉口设计方法的缺陷及原因,提出了一种新型的对称十字交叉口竖向设计方法——整体法,并介绍了该方法的原理、优势以及具体设计流程,评价以该方法设计所得的交叉口表面平顺,可提高行车舒适性,具有很高的应用价值。     

Operational performance comparison of four unconventional intersection designs using micro‐simulation

Several unconventional intersection designs have been proposed as an innovative approach to mitigate congestion at heavily congested at‐grade signalized intersections. Many of these unconventional designs were shown to outperform conventional intersections in terms of the average control delay and the overall intersection capacity. Little research has been conducted to compare the performance of these unconventional intersections to each other under different volume conditions. This study evaluated and compared the operational performance of four unconventional intersection schemes: the crossover displaced left‐turn (XDL), the upstream signalized crossover (USC), the double crossover intersection (DXI) (i.e., half USC), and the median U‐turn (MUT). The micro‐simulation software vissim (PTV Planung Transport Verkehr AG, Karlsruhe, Germany) was used to model and analyze the four unconventional intersections as well as a counterpart conventional one. The results showed that the XDL intersection constantly exhibited the lowest delays at nearly all tested balanced and unbalanced volume levels. The operational performance of both the USC and the DXI was similar in most volume conditions. The MUT design, on the other hand, was unable to accommodate high approach volumes and heavy left‐turn traffic. The capacity of the XDL intersection was found to be 99% higher than that of the conventional intersection, whereas the capacity of the USC and the DXI intersections was about 50% higher than that of the conventional intersection. The results of this study can provide guidance on choosing among alternative unconventional designs according to the prevailing traffic conditions at an intersection. Copyright © 2012 John Wiley & Sons, Ltd.     

协调路口划分对交通控制效果的影响分析

基于Synchro软件对干线协调的路口进行恰当地划分,Synchro软件中用协调因子来衡量相邻路口间是否需要实行协调控制,协调因子的计算主要考虑行程时间、距离、流量、车队形式、周期时长等因素;然后分析了干线协调优化逻辑,并用交通仿真的方法分析不同划分策略对控制效果的影响,并选取最佳的划分;对六一路全线11个交叉口进行案例分析,Synchro在协调路口划分中的有效性得到验证.结果表明协调路口划分会显著地影响整个网络中车辆的延误和停车次数,不恰当的划分会导致延误大幅增加.但不论哪种划分方式,都会显著减小主路和整个网络的停车次数.最佳的划分方式使整个网络延误降低10％,平均停车次数降低11％.     

信号控制平面交叉口非机动车交通安全分析

运用统计方法研究非机动车与机动车的交通冲突,分析了非机动车在信号控制道路平面交叉口的交通安全.研究表明,非机动车交通流率的增加将导致非机动车和机动车交通冲突的增加.对于机动车车头时距和非机动车及机动车的行驶速度而言,存在一个非机动车和机动车交通冲突的高发区域;而在该区域的左右两侧,交通冲突趋于减少.最后,针对非机动车交通安全的内在机理提出5项改善措施.     

基于冲突的公路平面交叉口驾驶行为研究

考虑每种驾驶行为对交叉口安全产生的影响不同,采用数据统计的方法赋予每种驾驶行为不同的权重。依据实际调查数据,统计分析交叉口各种驾驶行为的分布,提出驾驶行为特征值的分析方法和模型,并以驾驶行为特征值为自变量,建立了驾驶行为与冲突的关系模型,模型表明冲突率和驾驶行为特征值能够较好的符合线性关系．     

排阵式交叉口延误及最佳周期模型

为了提高排阵式交叉口这一非常规信号交叉口的运行效率，对其延误和最佳周期进行分析。首先针对先直行后左转、先左转后直行和直行左转交替通行3种信号相位相序，通过对排序区内车辆驶入、驶离、受信号控制阻滞等车流运行情况的分析，构建可反映排阵式交叉口车辆2次停车启动的车均延误计算模型。通过仿真对比可知，左转和直行延误估算误差均在10%范围内。在此基础上，以交叉口总延误最小为目标，考虑清空时长、主、预信号相位差、绿灯时长等约束条件，建立排阵式交叉口最佳周期理论模型。针对不同排阵式控制进口道数量设置的情况，通过对最佳周期的拟合分析，建立最佳周期简化模型。与理论模型相比，最佳周期简化模型的拟合优度在0.935~0.972范围内。通过模型对比和案例分析，对最佳周期简化模型的优化效益和稳定性进行检验。研究结果表明：在非饱和状态下，建立的最佳周期模型的平均误差和均方误差分别为2.13%和2.39%，均小于Webster模型和HCM2010模型的计算结果，具有较高的准确性和稳定性，案例中可降低车均延误36.46%；相较于传统信号控制交叉口，建议排阵式交叉口采用较小的周期时长，且当关键流量比大于0.6时尤为显著，分析中发现最佳周期减小14.53%~34.65%。     

交叉口行人过街心理及交通行为分析

行人与机动车的冲突是影响交叉口运行效率的重要因素。研究交叉口行人过街心理及行为的意义,分析行人过街过程及心理特征,总结行人过街等待时间、穿行速度特征、可接受间隙、违章行为及道路交通环境对行人心理和行为的影响,对行人的违章心理进行论述,并提出减少行人违章的措施。     

关于变革信号交叉口等候区域布局提高其通行能力的构想

针对机动车运行,在不改变交叉口现有规模的前提下,提出了“三等候区域、两相位信号控制、一左转过渡车道”交通运行模式,使信号交叉口的通行能力和服务水平产生了突破性的提高。结合国情,还给出了非机动车和行人的交通运行建议。     

Application of social force model to pedestrian behavior analysis at signalized crosswalk

Limited pedestrian behavior models shed light on the case at signalized crosswalk, where pedestrian behavior is characterized by group or individual evasion with surrounding pedestrians, collision avoidance with conflicting vehicles, and response to signal control and crosswalk boundary. This study fills this gap by developing a microscopic simulation model for pedestrian behavior analysis at signalized intersection. The social force theory has been employed and adjusted for this purpose. The parameters, including measurable and non-measurable ones, are either directly estimated based on observed dataset or indirectly derived by maximum likelihood estimation. Last, the model performance was confirmed in light of individual trajectory comparison between estimation and observation, passing position distribution at several cross-sections, collision avoidance behavior with conflicting vehicles, and lane-formation phenomenon. The simulation results also concluded that the model enables to visually represent pedestrian crossing behavior as in the real world.