关于城市道路合理间距理论推导的讨论

城市路网是城市交通与城市发展的骨架,对合理路网间距的认识是路网规划的关键。但对合理路网间距的认识存在若干观点,致使路网间距的合理取值范围较大。目前城市规划与交通工程专业书籍中经常提及的是路段通行能力的交叉口间距折减系数法和最佳公交线网密度分析法。本文采用逻辑推理的方法,指出路段通行能力的交叉口间距折减系数分析存在逻辑错误,公交最佳路网密度缺乏应有的应用前提分析,这些不足是导致我国城市路网密度不足的重要原因之一。     

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城市公共交通优先通行是公交优先发展的一个重要措施，交叉口公共交通的优先通行能够减少公交车在交叉口的延误，从而有效地保证公交车的准时性，提高公交的服务水平，促进公共交通的发展，对缓解城市的交通压力和保证城市未来的可持续发展都具有重大意义.在回顾了国内外交叉口公交优先研究现状的基础上，指出了目前我国交叉口公交优先通行技术研究中的主要问题和不足，并探讨了交叉口公交优先技术研究的发展方向.     

基于车队离散模型的交叉口关联度量化方法研究与试验

分析了常用的基于流量、距离、周期的交叉口合并控制原则,提出了综合因素关联度量化方法,考虑交通流量、交叉口距离、车队离散特性等因素,基于车队离散模型,构建相邻交叉口间关联度的量化公式,建立指标修正公式,结合实际分析模型的可靠性,获得反映综合因素的关联度值,为子区交通信号控制提供是否合并控制的决策支持。采用仿真软件进行模型应用,选择了具有典型意义的700 m相邻交叉口,以及4个交通流平稳上升的时段,进行关联度值计算,并根据是否合并的决策支持调整信号控制参数。结论表明:对于单一原则难以界定的边缘性合并判断,基于车队离散模型的量化综合判断方法能够有效地解决,并为交通信号协调控制决策。     

Customization of Automatic Incident Detection Algorithms for Signalized Urban Arterials

Non-recurrent congestion or incidents are detrimental to the operability and efficiency of busy urban transport networks. There exist multiple automatic incident detection algorithms (AIDAs) to remotely detect the occurrence of an incident in highway or freeway scenarios; however, very little research has been performed to automatically detect incidents in signalized urban arterials. This limited research attention has mostly been focused on developing new urban arterial specific algorithms, rather than identifying alternative methods to synthesize existing freeway-based algorithms for urban conditions. The main hindrance to such synthesis is that the traffic patterns on the signalized urban arterials are significantly different from the same on highways/freeways due to the presence of traffic intersections. This article introduces a new strategy of customizing the existing AIDAs (freeway based or otherwise) to significantly improve their adaptability to signalized urban arterial transport networks. The new strategy focuses on preprocessing the traffic information before being used as input to a freeway/highway-based AIDA to lessen the effect of traffic signals and to imitate the input patterns in highway/freeway-based incident conditions. The effectiveness of this new strategy has been established with the help of four existing AIDAs. The proposed strategy is a simple solution to implement existing algorithms to signalized urban networks without any further instrumentation or operational cost.     

苏州有轨电车1号线交叉口交通组织分析

有轨电车占用一定道路资源,对沿线交叉口交通运行产生影响。以苏州有轨电车1号线为基础,分析了有轨电车带来的影响,提出交通组织总体策略,并分析不同轨道布设方式下的交叉口冲突特点,结合案例阐述了交叉口范围内有轨电车、机动车、非机动车、行人和乘客的交通组织方式。总结了苏州有轨电车1号线交叉口交通组织经验,为以后的有轨电车沿线交通设计提供参考。     

Proposed quick method for applying dynamic lane assignment at signalized intersections

Almost all researches about dynamic lane assignment were conducted to evaluate the effectiveness of applying this technique at signalized intersections. However, little attention was given to the method of identifying quickly the optimum lane group. This research suggests a quick method to find the optimum lane group for 3-lane and 4-lane approaches at junctions where each approach has green by itself in turn using the percentage of turning movements. MATLAB environment was used to build an optimization model to find the optimal lane groups at all intersection approaches for hypothetical massive traffic demand combinations using an objective function of minimizing intersection delay. This finding represents a plausible quick method to predict the optimum lane group in the field instantaneously using the percentage of turning movements at the approach without conducting massive calculations.     

无信号控制交叉口行人专用信号的设置标准研究

通过对城市道路无信号控制交叉口行人穿越特性的分析,总结出反映行人穿越效率的3个主要效率指标。对现有行人临界穿越间隙的计算公式进行合理、全面的修正,得出将总的行人平均延误30 s作为行人控制信号的1个设置标准。同时,采用行人可穿越机会数（CO）和当量行人流量（EAU）指标来建立模型,作出基于行人特性的信号设置依据图形,作为行人控制信号的另一个设置标准。最后对按钮式行人信号灯的基本原理和适用条件作了简要分析。     

信控交叉口提前右转机动车与行人冲突特性

针对在信号交叉口提前右转且无信号控制的条件下,直右混行车道上右转车受直行车阻挡的问题,根据混行车道上交通流特性,确定了交叉口信号周期内提前右转机动车无法进入右转弯道的阻断时间,结合行人流上游所受的信号控制方式,解析了机动车与双向行人的冲突过程,计算了冲突中机动车与行人的通行时间,并在此基础上,建立了提前右转方式下右转车与行人的延误模型.案例计算与分析表明:模型计算值与实际调查值之间的相对误差在20%以内;当机动车流量小于350 pcu/h,机动车对行人通行影响较小,而当机动车流量大于350 pcu/h,行人与机动车的竞争冲突较为明显.      

基于信号配时的路网交通流分析及优化研究

文章以南宁市四条主干道上七个交叉口组成的闭合路网为优化对象,通过交叉口交通流量分析,利用R.Kimber饱和流量计算法和F.Webster交叉口信号配时理论,初步拟定车辆延误最小的信号配时方案,然后使用遗传算法优化配时方案,最后利用VISSIM进行交通仿真,验算服务水平指标的变化,验证该优化方案。