武昌徐东路口交通疏解方案研究

武汉市武昌徐东路口为和平大道与武青三干道十字交叉路口，紧邻武汉长江二桥。是连接汉口与武昌的重要枢纽。针对徐东平价地段现状交通量组成及远景交通量发展趋势。提出了改善交通状况的近远期方案，分析了各交通疏解方案的功能及优缺点，提出了适合徐东路口交通状况的近远期建设方案。     

温州汤家桥路—机场大道交叉口交通组织方案

汤家桥路—机场大道交叉口为主干路相交形成的五叉路口,通过利用左转二次控制方法,降低交叉口混乱程度,极大地提高了环行交叉口的通行能力。     

基于车流冲突线的无信号交叉口风险分析

为更客观、系统地分析无信号交叉口的安全性能,提出“车流冲突线”概念.通过分析首部车冲突概率、碰撞后严重程度比和冲突向后传递长度,构建无信号交叉口安全风险评估模型.研究表明：基于临界冲突距离值构建的首部车冲突概率模型,考虑两车速度、角度、加速度和反应时间,更接近交通冲突的真实过程;借助物理碰撞学原理可确定 3种冲突型态碰撞严重程度的权重关系,即,交叉∶合流∶分流为 12.705∶1.000∶1.000;利用数学期望知识建立的交叉口当量期望车流冲突量模型,综合考虑冲突发生的潜在机率、交通量大小、车辆位置等因素,可更真实描述实际车流冲突行为.     

城市公交停靠站设置常见问题及对策

公交停靠站设置不合理,会导致道路通行能力的下降,针对目前城市公交停靠站设置常见的问题,根据公交线路走向、道路横断面形式及交叉口的交通状况,结合公交停靠站类型、规模与道路用地可能条件等情况,从减少公交车辆和其它非公交车辆相互干扰的角度出发,给出解决这些问题的可行方案。     

Quasi-optimal feedback control for an isolated intersection under oversaturation

How to manage signalized intersections under oversaturated conditions is a long-standing problem in traffic science and engineering. However, although research works in this area date back to 1960s, an on-line control strategy with theoretically bounded performance is missing, even for the control of an isolated intersection under oversaturation. This paper makes one step further in this area by proposing a QUEUE-based quasi-optimal feedback control (abbreviated as QUEUE) strategy for an isolated oversaturated intersection. The QUEUE strategy is intuitive, simple, and proved to match the off-line optimum in the case of constant demand. More importantly, the bounds of sub-optimality of the QUEUE strategy can be specified quantitatively in general piece-wise constant demand cases. To better deal with the maximum queue constraints, the oversaturation period is divided into the queuing period and the dissipation period with two different objectives. In the queuing period, the primary objective is to keep the queue length within the maximum value; but for the dissipation period, the primary objective is to eliminate all queues at the earliest time. Interestingly, we found that both control objectives can be realized with the same QUEUE strategy. Numerical examples show that the QUEUE strategy approximates the off-line optimum very well. The average sub-optimality in comparison with the off-line optimum in the challenging conditions with Poisson distributed random demand is below 5%.     

Improved driver responses at intersections with red signal countdown timers

Traffic Signal Countdown Timers (TSCTs) are innovative, practical and cost effective technologies with the potential to improve efficiency at signalized intersections. The purpose of these devices is to assist motorists in decision-making at signalized intersections with real-time signal duration information. This study focused specifically on driver responses in the presence of a Red Signal Countdown Timer (RSCT). A Linear Mixed Effect (LME) model was developed to predict the effect of RSCT on the headway of the first vehicle waiting on a red signal. The model predicted 0.72 s reduction in the headway of the first queued vehicle resulting from the presence of RSCT, while the observed difference in mean headway was 0.82 s. This result is suggestive of a reduction in start-up lost time at signalized intersections, i.e., an improvement in signalized intersection efficiency when an RSCT is present.     

路段U型掉头设置的适用性研究

左转是产生冲突点最多、对交叉口影响最大的一个流向。U型掉头在改善左转与进出交通对干路车流的影响方面具有较大的作用。该方式已在我国一些大、中城市干路有所应用,但并不尽如人意。该文在分析路段U型掉头设置表层原因的基础上,从路口、路段设计、过街设施配置层面阐述我国U型掉头设置的深层次原因。并对U型掉头的适用条件、掉头区的数量、计算方法展开讨论。研究认为,U型掉头是弥补路口、路段设计缺陷的有效方法,但不是常用方法;优化断面、健全路口、合理设置过街设施是道路设计需首先考虑的任务。     

立交匝道的超高与横坡

为配合建设部《城市道路交叉设计规程》的编写 ,本文根据目前道路超高与横坡设计的习惯做法 ,结合国内外已取得的成功经验 ,针对城市立交匝道 ,从道路条件和行驶舒适性分别阐述了最大横坡和横向摩阻系数的取用原则 ,对比了超高与横向摩阻系数在平衡车辆行驶于弯道所产生的侧向离心力的各种组合及协同作用 ,总结提出了适合我国的立交匝道超高与横坡设计的各项设计指标和设计方法。     

平面交叉口中的交通岛设计方法初探

论文首先讨论了不同类型交通岛的特点及其适用性,然后从交通岛的形状、大小、鼻端设计等方面,针对平面交叉口中的交通岛设计方法进行了详细的分析研究,提出了交通岛的设计方法。     

公路平面交叉口安全养护评价方法

为评价公路平面交叉口结构损坏对行车安全性的影响,遵循表征性、综合性、明确性、实用性的原则,对交叉口功能区内路基路面、交通安全设施、照明设施和交通管理设施提出了22项评价指标,运用层次分析法进行两两比较确定指标相对重要性,建立了安全养护评价体系。应用结果表明,该评价方法具有良好的可操作性,对公路平面交叉口的安全保障和养护工作起到指导作用。