信号控制路段行人二次过街设置标准

从时空资源利用角度和延误角度对有信号控制路段行人二次过街进行分析,在对路段行人信号配时方案设计基础上得到有信号控制条件下行人延误公式。在一定路宽、行人流量条件下,以行人延误小于其极限忍耐时间为判定标准,得出二次过街允许的机动车流量范围,在该范围内设置二次过街可兼顾道路时空资源的利用和行人安全。研究表明:与一次过街相比,二次过街可更有效利用道路时空资源,同时行人每次获得通行权所需等待时间显著减少。     

城市行人过街行为特性调研分析

采用调查问卷对城市行人过街行为开展调研，从行人过街设施选择行为、驾车人群对行人横穿道路态度、行人违章特性和有效行人绿灯时间感知分析等方面进行研究分析。通过了解行人过街行人特性，为更加合理的优化行人过街设施设置，规范行人过街和机动车驾驶行为提供理论支持。     

城市道路行人相位切换方式评价研究

城市道路上行人过街交通与机动车交通的矛盾是造成行人过街不安全和机动车延误的主要原因,设置行人相位切换方式对解决人车冲突问题有重要作用。针对现有的行人相位切换方式展开研究,提出评价方法,通过实际调查数据进行理论分析,最后得到最佳的行人相位切换方式。     

路段感应式信号控制行人过街系统设计

为保障路段行人安全过街,提高行人过街效率,设计了基于感应控制的路段行人安全过街系统.该系统分别采用视频和感应线圈实现对过街行人和路段车辆的自动检测,并据此设计行人过街感应信号控制方案,辅以“减速带式”人行横道、路段行人过街通道灯和智能人行道护栏3种过街辅助设施,实现时空上的人车分离.     

不同控制方式下路段人行横道交通状况的对比分析

人行横道因其建设维护费用低、行人过街便捷等特点,被广泛地应用于行人过街的交通组织之中。在不同控制方式下的人行横道上,行人过街存在不同的问题。以北京市展览馆路段为例,针对有无信号灯控制路段人行横道的交通状况进行了交通调查,在对比分析调查数据的基础上,从行人过街效率、机动车通行效率以及人行横道安全性3个方面,探讨不同的路段人行横道控制方式对交通流的影响。     

考虑与过街行人冲突的道路右转机动车延误研究

以道路信号交叉口右转机动车和过街行人为研究对象,通过从微观角度分析无信号控制的右转机动车与过街行人冲突过程,考虑右转机动车在等待一段时间后与行人抢行状况,建立右转机动车交通延误模型(简称DRT模型)。以长沙市3个信号交叉口为例,将相关参数代入延误模型计算,并与VISSIM仿真结果进行对比,发现3个信号交叉口右转机动车延误值分别存在1.59%、2.59%、2.67%的误差,表明该模型具有一定的准确性。     

城乡结合部行人-机动车冲突及安全性分析

为了分析我国城乡结合部的行人过街安全情况,使用交通冲突和行人安全性指标对城乡结合部行人过街进行了探索。对行人和机动车冲突的特点进行了分析,并介绍了行人和机动车冲突的形成过程。通过现场调查视频和人工提取,获取相关参数,计算得到了行人和机动车冲突的距碰撞发生的时间和后侵占时间指标,并使用行人安全性指标对行人过街的安全性展开了分析,结果表明,所调查的地点均处于不安全的状况,设施设置越齐全,车流量越少,行人的安全性越高。     

基于延误时间最小的右转专用信号设置条件研究

为减少右转机动车与过街行人之间的冲突,提出了设置右转专用相位的控制方法。首先利用交通冲突技术分析了无右转专用相位时右转机动车与行人的冲突情况,并计算了不同情况下右转机动车穿越行人、行人穿越机动车的临界穿越间隙,提出穿越概率;其次提出了基于总延误时间最小的右转专用相位设置条件;再次利用交通流理论分析了有无右转专用相位两种情况下右转机动车以及行人的延误时间模型;最后,以一典型十字信号交叉口为例,运用延误模型,比较了不同流量下有无右转专用相位两种情况的总延误,并给出了不同流量的情况下设置右转专用相位的临界值。     

无信号灯控制下行人过街对机动车流的影响

行人过街问题是引起中国城市道路交通秩序混乱、安全隐患大、交通效率低的主要根源之一。文中分析了城市路段间行人过街特性,通过引入双车道换道规则、行人过街对机动车流干扰规则,提出了一种无信号灯控制下基于元胞自动机的行人过街模型。数值模拟研究表明随着机动车流密度的增加,行人过街对机动车速度及流量的影响降低,当密度超过一定值后行人无法过街,因而不会对机动车流造成影响;随着行人可接受穿越空档的减小,行人过街对机动车行驶的干扰加剧,对快车道车辆行驶的干扰比慢车道明显。     

行人立体过街设施选址及选型方法研究

近年来随着经济社会的不断发展,城市机动化增长迅速,城市机动车拥有率大幅提升。在城市中心区,特别是商业集中区,机动车与行人抢道、混行的现象较为突出,影响道路通行能力,威胁行人过街安全。通过对高品质立体过街设施案例的总结,对既有规范的分析评价,提出了立体过街设施设置条件、布局、选型的影响因素,并结合各种因素提出了规划设计阶段进行相关分析的方法及流程。     

立体过街设施选址模型初探——以天津滨海新区过街天桥规划为例

立体过街设施是行人安全过街的主要保障措施,立体过街设施的选址是否合理关乎人们使用的便利性设施的利用率.结合行人过街特点布置立体过街设施可以大大提高设施使用率,同时也方便行人的安全过街.行人交通作为城市交通不可忽视的重要部分,通过分析国内外行人过街设施间距、行人交通特性,尝试提出立体行人过街设施选址模型.结合滨海新区的交通特性和城市用地发展布局,将行人过街设施模型进行应用,从而提出立体过街设施规划方案.     

基于心理安全距离的行人风险评价及预警算法研究

为实现在机非混行的交通环境下,对动态、随机弱势道路使用者的准确风险评估,基于行车安全场理论提出了考虑行人心理安全距离的碰撞行人风险评价模型.首先通过考虑行驶车辆是否会危及行人的心理安全,提出了心理安全距离的概念,包括心理安全通行距离和心理安全制动距离2个方面,并通过问卷调研挖掘其可能的影响因素进行数值分析;接着将心理安...     

行人穿越车流的特征性研究

在实地调查测量的基础上,通过统计分析行人穿越车流时的平均步行速度,行人所需要的穿越时间,综合运用交通工程学和心理学理论,分析了影响行人穿越车流的各个因素的特征,得出行人穿行车流过街的流程图,并对防治行人穿越车流过街的违章行为的发生提出了一些建议。     

基于累积前景理论的无信控路段人车通行冲突博弈分析

无信控路段具有强交互性和高事故率,由于缺乏交通信号将人车进行分离,导致其容易形成人车通行冲突,影响道路通行效率和交通安全.为此,以各道路使用者的损失最小为目标,构建了基于累积前景理论的人车通行冲突博弈模型.通过研究过街行人与机动车辆的交互作用,分析双方决策行为影响因素并构建得失矩阵;同时在考虑决策者主观心理感知的前提下...     

行人立体过街设施及“第二套步行系统”的合理设置

目前交通问题已经是每个城市,特别是一些大城市不得不面对的严峻问题。虽然城市交通规划已经逐渐走向成熟,但是尚处在发现问题、解决问题的层面,尤其是很多交通规划只注重车辆交通的问题,而忽视了与之相关的行人交通及行人的横向交通对机动车流的影响,道路过街处人车矛盾尤其突出。“人车分离,立体过街”将成为行人过街的主要方式。该文阐述行人立体过街交通设施的规划,介绍“第二套城市步行系统”的概念,并深入地研究其存在的优越性和必要性。     

Macroscopic analysis on the frequency and severity of pedestrian crashes on National Roads in Metro Manila,Philippines

Pedestrians are the most vulnerable road users; thus, understanding the primary factors that lead to pedestrian crashes is a chief concern in road safety. However, owing to the limitations of crash data in developing countries, only a few studies have evaluated the comprehensive characteristics of pedestrian crashes, specifically on different road types. This study attempted to develop pedestrian crash frequency and severity models on national roads by using the road characteristics and built environment parameters, based on the road crash data (2016–2018) that involved pedestrians in Metro Manila, Philippines. Remarkable findings included primary roads, presence of footbridges, road sections with bad surface conditions, and increased fractions of commercial, residential, and industrial roads, which exhibited a greater likelihood of pedestrian crashes. Crashes involving elderly pedestrians, heavier vehicles, late-night hours, fair surface conditions, and open spaces were associated with increased likelihoods of fatal outcomes. Essentially, this study provides a macroscopic perspective in understanding the factors associated with the severity and frequency of pedestrian crashes, and it would aid the authorities in identifying proper countermeasures.     

Exploring pedestrian surrogate safety measures by road geometry at midblock crosswalks: A perspective under mixed traffic conditions

Pedestrian safety is generally assessed using frequency of crashes, based on historical data, for a given transportation facility. However, the lack of good and reliable crash data has hampered its apposite analyses and in evaluating the effectiveness of pedestrian safety programs. To overcome this gap, traffic conflict technique (TCT) which relies mainly on the observations of critical traffic situations for safety analysis were developed. However, the applicability of TCTs and related measures under varying non-lane based heterogeneous traffic conditions prevailing in countries such as India is not widely explored. This paper attempts to evaluate pedestrian safety at urban midblock crosswalk using different surrogate safety measures, including vehicle crossing speed, post encroachment time (PET), yielding compliance of driver as well as pedestrian, and conflict rate. The number of conflicts were observed to increase as the average vehicle crossing speed increases, indicating that pedestrians are extremely vulnerable while crossing the road. The PET value for the smaller vehicles, such as two-wheelers and three-wheelers, is recorded to be lower than the heavy vehicles, such as trucks and buses. With the addition of one lane, there is a significant decrease in the PET value. The average PET values for the vehicle on eight-lane divided road is less than the six-lane divided, four-lane divided, and two-lane undivided roads. Further, the yielding compliance of the driver as well as of the pedestrian depends on the crossing speed of the approaching vehicle and the type of road geometry. Further, the rate and severity of conflicts increased with a decrease in the pedestrian crossing speed. The yielding behaviour of the drivers as well as the pedestrian's yielding compliance varies by location, highlighting the effect of individual and demographic characteristics on pedestrian crossing behaviour.     

典型信号控制交叉口行人专用相位设置阈值研究

针对目前城市道路交叉口中人车混行现象,综合考虑效率与安全两方面因素,选取延误成本和冲突成本分别作为效率与安全的评价指标,构建有(无)行人专用相位信号控制模式的交叉口运行成本模型.模型的延误成本中,行人和非机动车延误考虑了信号延误、冲突延误以及绕行延误;冲突成本则基于交通冲突理论,以车头时距判断机动车与行人和非机动车是否发生冲突为指标,并根据机动车及行人和非机动车达到分布确定冲突概率.最后,通过北京市四道口交叉口验证了该模型的适用性,并基于遗传算法求得典型信号控制交叉口中行人专用相位设置的阈值在750~900人/h浮动,随着车流量的增长,行人专用相位的设置对行人流量的要求呈现先降后升的趋势.为城市道路交叉口信号配时设计提供了理论支撑,保障行人及非机动车安全、舒适、方便、尊严的出行.      

What affects pedestrian crossing difficulty at urban intersections in a developing country?

In developing countries, road traffic crashes involving pedestrians have become a foremost concern. At present, road safety assessment plans and selection of interventions are primarily restricted to traditional approaches that depend on the investigations of historical crash data. However, in developing countries such as India, the availability, consistency, and accuracy of crash data are major concerns. In contrast, proactive approaches such as studying road users' risk perception have emerged as a substitute method of examining potential risk factors. An individual's risk perception offers vital information on probable crash risk, which may be beneficial in detecting high-risk locations and major causes of crashes. Since the pedestrian fatality risk is not uniform across the urban road network level, it may be expected that pedestrians' perceived risk measured in terms of “crossing difficulty” would also vary across the sites. In this perspective, the present paper establishes a mathematical association between the pedestrians' perceived “crossing difficulty” and actual crashes. The model outcome confirms that pedestrians' perceived crossing difficulty is a good surrogate of fatal pedestrian crashes at the intersection level in Kolkata City, India. Subsequently, to examine the impact of traffic exposures, road infrastructure, land use, spatial factors, and pedestrian-level attributes on pedestrians' “crossing difficulty”; a set of Ordered Logit models are developed. The model outcomes show that high vehicle and pedestrian volume, vehicular speed, absence of designated bus stop, the presence of inaccessible pedestrian crosswalk, on-street parking, lack of signalized control (for both vehicle and pedestrian), inadequate sight distance, land use pattern, slum population, pedestrian-vehicular post encroachment time, waiting time before crossing, road width, and absence of police enforcement at an intersection significantly and positively increase pedestrian's crossing difficulty at urban intersections. To end, the model findings are advantageously utilized to develop a set of countermeasures across 3E's of road safety.     

Pedestrian injury outcomes in the developing urban metropolis: Econometric models for assessing risk factors

Pedestrian fatality and injury is one of the most concerning issues around the globe. The predictors for such mishaps have been investigated in the developed countries through econometric models and are proven useful techniques. Such studies in the context of developing countries, especially for urban cities, are however still very scarce. Using five years reported pedestrian crash data, this study looks into the performance of three statistical models - Multinomial Logit (MNL), Ordered Logit (OL) and Partial Proportional Odds (PPO) model while examining the impact of various attributes related to pedestrian crashes severity outcomes for Dhaka metropolitan city in Bangladesh. The comparative analysis reveals that the performance of the PPO model is relatively better for the available dataset in terms of identifying critical risk factors. Undivided roadway, heavy vehicles, unfit vehicles, adult drivers with no seat belt use, young and older pedestrians, pedestrian road crossing action are found to be associated with higher probability of fatal injuries. In contrast, one-way traffic movement, daytime, motorcycles and mid-aged pedestrians decrease the likelihood of fatal injury. Based on these identified risk factors, a combined 3-E approach has been suggested to reduce the severity levels of pedestrian in the event of crash occurrence.