Problems in Ecological Landscape and Traffic Safety of Urban Roads

This study mainly analyzed problems in ecological landscape and traffic safety of urban roads, and in view of these problems, proposed the design concepts, principles and focuses of urban road eco-landscape ensuring traffic safety.

Traffic Organization Optimization of Urban Road Combined Intersections

With the development of the economy and the acceleration of urbanization, the number of vehicles in cities is increasing rapidly, which greatly increases the pressure on urban traffic. Solving traffic accidents and problems to keep smooth travel and safe travel has become a top priority in road construction. In this paper, how to optimize the traffic at the intersection of the urban road was discussed with the aim of reducing traffic accidents and problems to keep peoples’ smooth travel and safe travel.

An Evaluation of Measures Regarding Road Traffic against the Urban Heat Island in the Tokyo Ward Area, Japan

This study aims to evaluate measures against the Urban Heat Island (UHI) regarding artificial exhaust heat of road traffic using Geographic Information Systems (GIS) in the Tokyo Ward Area where the degree of UHI is particularly strong. We developed a GIS database that reflected road traffic conditions, and calculated the volume of artificial exhaust heat of road traffic to evaluate measures against the UHI. The findings of this study can be summarized in the following three points. 1) Artificial exhaust heat volume for moving targets was remarkably higher than that of stationary targets and, in particular, artificial exhaust heat volume was high on roads with remarkable numbers of vehicles and running speeds such as expressways and ring roads. 2) In UHI- related policy for moving targets, the suppression of waste heat through choice of fuel burned, improvement of traffic flow by securing space for cyclists and pedestrians, development of bypasses, and upgrading signal control managed to reduce artificial exhaust heat volume, even though there were differences in degree of reduction. 3) In UHI-related policy for stationary targets, special road surfaces and the increase in efficiency of energy consumption equipment achieved a reduction ratio of around 30% in artificial exhaust heat volume, more than moving targets as well as making it possible to expect a reduction in artificial exhaust heat volume on a wide scale.

Effect of Residential Quarters Opening on Urban Traffic from the View of Mathematical Modeling

With the great prosperity of national economy, there has been a dramatic rise of vehicles on city road, which makes increasing pressure of road transportation. Currently, many countries are confronting the severe situation of traffic jam in different degrees. Nevertheless, there are many triggers contributing to this congestion, one of which is the blocking of residential quarters towards vital traffic line. Therefore, it is extremely necessary to study whether the opening of residential quarters can improve the road capacity of the entire city and remit the traffic pressure. Our paper is based on graph theory, density theory and random utility theory. First of all, we demonstrate a mathematical model of road traffic. Secondly, we explore the influence of residential quarters opening on urban traffic, taking three factors into account listed as road traffic capacity, road network density and network average running time. On the basis of above contents, the impact analysis of vehicle traffic caused by pedestrians is added afterwards. Finally, our paper takes three different types of residential areas into account as an example to empirically analyze the tangible impact of the opening, and finally come to the benefit of the traffic system after the opening.

Application of GIS for Urban Traffic Accidents: A Critical Review

The analysis of huge data is a complex task that cannot be executed without a proper system. Geographic information systems (GISs) have been used by many transportation agencies and police departments to analyze and manage urban traffic accident (UTA) data and for decision making aimed at decreasing accident rates and increasing safety. The exact location of accidents and environmental characteristics must be analyzed as UTAs occur in specific locations with specific characteristics. ArcGIS software is the best choice for obtaining meaningful information and analysis results from UTAs in an observational time span. GIS technology is a fundamental element for investigating and evaluating the complex spatial relationship among different components and urban traffic accident is one of them. Micro or macro analysis of UTAs through the spatial prospective within the geographical environment and urban structure can make a deep micro understanding of UTAs patterns in addition to assisting in decision making. UTAs can be considered complex events that occur in two aspects which are spatial and temporal or space and time in other word. A GIS can integrate more than two different and unrelated databases. The evaluation among different spatial objects in a geographical environment and associated factors in urban structure which are included but not limited to land use category, road transportation network qualification, population density, etc., is one of the GIS specification. Traffic safety organizations and UTA researchers use GISs as a key technology to support their research and operational needs. In particular, GIS-T is an often-used GIS application used for planning and decision-making in transportation.

Characterizing Peak-Time Traffic Jam Incidents in Kampala Using Exploratory Data Analysis

Traffic congestion is associated with increased environmental pollutions, as well as reduced socio-economic productivity due to significant delays in travel times. The consequences are worse in least developed countries where motorized road transport networks are often inefficiently managed in addition to being largely underdeveloped. Recent research on traffic congestion has mostly focused on infrastructural aspects of road networks, with little or no emphasis at all on motorists’ on-the-road behavior (MB). The current study thus aimed to bridge this knowledge gap by characterizing traffic jam incidents (TJI) observed over a period of 80 days in Uganda’s Capital City, Kampala. MB as well as road network infrastructural factors such as road blockage (RB), were captured for each of the observed TJI. A total of 483 peak-time TJI were recorded, and exploratory data analysis (EDA) subsequently performed on the TJI dataset. EDA involved Hierarchical clustering analysis (HCA) and K-means clustering of the TJI dataset, as well as a detailed descriptive statistical analysis of both the entire dataset and the emerging TJI clusters. A highlight finding of this study is that 48.2% of the observed TJIs were as a result of on-the-road motorist behavior. Furthermore, the intervention of traffic police officers in a bid to regulate traffic flow was equally responsible for 25.9% of the TJIs observed in this study. Overall, these results indicate that whereas road infrastructural improvement is warranted in order to improve traffic flow, introducing interventions to address inappropriate on-the-road motorists’ behavior could alone improve traffic flow in Kampala, by over 48%. Additionally, in-order to effectively regulate traffic flow in Kampala and other least developed cities with similar traffic congestion management practices, motorists’ on-the-road behavior ought to be factored into any data-driven mechanisms deployed to regulate traffic flow and thus potentially significantly curbing traffic congestion.

城市主干路交通隔离栏设置对驾驶人规避效应的影响

为探究城市主干路交通隔离栏的设置对驾驶人规避效应的影响,利用无人机采集了3处设置了交通隔离栏与2处未设置交通隔离栏的主干路的车辆行驶数据、行车环境与交通量,根据车道与交通隔离栏横向距离对车道进行了分类,明确了交通隔离栏影响下的驾驶行为特性与规避效应形成机制.研究结果表明,不同车道内的轨迹偏移量存在着显著差异性,目标车道偏移中心相对频率峰值大于零,其他车道则在-0.1~0.1 m范围内波动.车道区域对轨迹偏移的影响最大,其次为相邻车道交通量、速度、标线与交通隔离栏的组合类型.交通隔离栏的设置会造成驾驶人的规避效应,减少了左偏与对向来车的冲突,从而规范了行车轨迹,控制了行车速度,在出口和入口分别减速约5.1%和19.3%.但不良的设施与标线的组合形式易引起规避效应过量而致使轨迹向右偏移过大(大于0.85 m)而侵占其他车道,增加行车风险.当交通隔离栏底座与车道边线间距大于15 cm(单边)时,规避效应所带来的影响处于最佳水平.

西安市幸福路跨陇海铁路总体方案研究

随着城市发展以及对中心区域的提质优化,那些在中心城区中存在的特别难以优化提升且制约因素较多的断头路,近些年来越来越引起相关职能部门及领导的重视。本文通过对交通瓶颈区域的建设空间进行调查,分析总结了通道限制因素,以提高区域交通效率、均衡路网流量、增强交通服务功能等为目标,通过系统性地对交通状况进行分析,优化立交节点方案,强化通道的可实施性,以期为今后类似通道项目设计提供技术参考。

暴雨内涝下城市路网抗涝韧性评估

极端降雨给城市路网的正常运行带来了极大挑战,为了评估在应对极端降雨时路网的抗涝韧性,本文采用场景模拟方法分析暴雨内涝灾害对路网的影响;以道路水深是否超过水深阈值为标准,判断道路的连通性,构建以节点强度和不同水深下道路速度的衰减函数为计算指标的综合评价框架;基于降雨—积水过程下道路系统的性能变化曲线和4R特征理论,分析4种暴雨重现期下路网的抗涝韧性;提出通过改造易涝交通枢纽提高路网抗涝韧性的提升策略。结果表明:降雨对路网服务性能的影响要大于对路网结构性能的影响,路网的抗涝韧性随着降雨重现期的增大而减小,道路的淹没程度与道路等级和降雨强度两个方面有关;易涝交通枢纽对路网抗涝韧性有较大影响,降雨重现期越小,影响越大。在实施提升策略后,可以显著提升路网的鲁棒性和快速性,增强路网的抗涝韧性。

考虑建成环境的交通事故严重程度致因交互效应研究

为探究考虑建成环境影响下各类因素对交通事故的作用机理,本文提出一种融合ADASYN(Adaptive Synthetic Sampling)平衡算法与CatBoost模型的方法,对沈阳市2015—2020年的道路交通事故进行研究,并解析事故致因的交互效应。首先,通过地理信息匹配的方法补充事故地点周围14项建成环境因子,构建多源数据集。其次,通过比较4种经典的机器学习模型,即CatBoost,Random Forest,XGBoost,LightGBM,并筛选出泛化能力最强的模型。随后,利用SHAP(Shapley Additive Explanation)归因方法对最优模型进行解释以揭示单个风险因素效应以及影响重要度排序。最后,基于单因素分析,探究建成环境与事故特征之间的交互效应。研究表明:相同的特征在单因素以及双因素交互分析中对事故影响机制存在差异。在单因素分析中,季节、交通方式这2项因素对致命事故具有显著的正向影响;而主干路密度、快速路密度、工业用地比例、现场形态、道路物理隔离这5项因素对致命事故有着显著的负向影响。在双因素交互分析中,高主路密度与秋冬季节交互以及低工业用地比例与春季交互等对致命事故具有正向影响;而高工业用地比例与行人交互则产生了负向影响。本文成果可为相关人员提供准确的影响交通事故严重程度的相关因素,为优化和建设城市交通系统提供一定的理论支撑。

基于改进DEMATEL-ISM模型的道路拥堵下行车风险评估方法

为准确识别城市道路拥堵条件下的行车风险系统中各影响因素之间的内在联系以及该系统中的关键因素,本文提出一种改进DEMATEL-ISM的评估方法。首先,分析城市道路拥堵条件下的行车风险,选取18个风险因子;其次,运用多群体问询的调查问卷方法,并结合最大类间方差法对标准的集成决策试验和评价试验室(DEMATEL)以及解释结构模型(ISM)改进,建立城市道路拥堵的行车风险评估模型。最后,实例验证结果表明:基于改进DEMATEL-ISM模型的道路拥堵条件下行车风险评估体系能准确划分层次解释结构图的层级,与其他方法相比更加符合实际;交通密度、车头时距、停车次数、换道频次等关键链接因素对其他因素有较强联动影响,并且会增加发生交通事故或二次交通拥堵的概率。

基于ICAE算法的城市群高速公路网布局优化研究

为提升城市群高速公路网通达程度和可达性水平,建立了体现城市群特征的优化模型,并改进了帝国竞争算法,以哈长城市群为案例,探究布局优化效果。采用高速公路出行时间确定城市群可达性等级,通过考虑可达性、距离等参数建立优化模型;引入进化算子改进算法,构建进化帝国竞争算法;根据哈长城市群特征确定约束条件并求解,利用求解节点和周边道路网确定优化方案。研究表明:改进的算法收敛精度提高16.4%,时间缩短42.4%,共求解出6个节点,规划新建高速公路6条,改建高速公路14条,优化后的城市群高速公路2 h交通圈覆盖范围达到65.3%,14个县域交通圈等级上升,优化方案扩大了城市群2 h交通圈范围。

灾害应对措施下的北京道路拥堵时空变化

暴雨灾害给城市正常运转带来了巨大挑战,道路交通由于直接暴露在户外、承载多种出行方式和海量刚需活动,需要重点关注与积极应对。该研究以北京五环内为研究区,使用精细的道路拥堵数据,从时空维度评价了2021年北京最大暴雨事件及多种应对措施下的交通状况。结果表明:①道路拥堵在常态下具有鲜明的日际、周际规律,而降雨和应对措施会导致极其显著的变化;②拥堵变化的时间序列呈现对勾形态,即暴雨当日拥堵缓解,而前后日拥堵加重,体现了应对措施的阶段性效果;③城市内部的拥堵变化具有空间异质性,暴雨当日北部和东部地区的拥堵大幅缓解,而次日拥堵整体加重且高度聚集;④分时段分区域统计显示,早高峰和环线的拥堵变化最为强烈;⑤相关性分析识别了应对措施的有效作用对象,证实了众多行业部门对于暴雨预警的积极响应以及弹性上下班建议的执行成效。研究发现,暴雨应对措施在局部上有效减轻了交通压力,但伴随的拥堵转移现象需要在实施应对措施前被充分考虑。

基于博弈论组合赋权云物元模型的城市道路交通系统风险评价

为保障城市道路交通系统安全运行,降低城市交通事故发生概率,提出了一种基于博弈论组合赋权云物元城市道路交通系统风险评价模型。从城市道路交通系统风险因素出发,结合《城市道路交通管理评价指标体系》,选取实习期驾驶员比例等15个风险评价指标,构建“人-车-道-环”评价指标体系。基于云物元模型,解决评价指标中存在模糊性与随机性的问题,同时采用博弈论将C-OWA有序加权算子处理的专家打分值和改进熵权法求出的权重进行组合优化,围绕待评物元与风险等级之间的隶属度,计算得出风险等级。将该模型应用于中国西部某城市A道路交通系统,展开风险评价,同时将该模型的评价结果与C-OWA云物元模型和熵权云物元模型的评价结果进行对比。结果表明:该模型得出城市A道路交通系统中各指标风险评价结果与实地走访调研结果及实际情况基本一致,且博弈论组合赋权云物元城市道路交通系统风险评价模型更加具有实用性和有效性,可为城市道路交通系统风险评价提供新思路。

城市道路交通噪声频谱及其对隔声评价中频谱修正量的影响

现行隔声评价标准中交通噪声频谱修正量参考的是20世纪80年代北欧测量得到的交通噪声数据。为了研究C_(tr)修正量是否适用于评价建筑外窗对新时代城市道路交通噪声的隔声性能,对多种城市交通道路进行噪声监测,根据测量结果提出一组新的交通噪声频谱修正曲线C_(A),计算11种常见外窗构造在不同频率范围内的计权隔声量,并对比分析不同频谱修正量声压级频谱的差异性。结果表明:不同城市道路交通噪声频谱都具有低频声压级高、中频平稳、高频下降的相似特点;当今的城市道路交通噪声低频能量远低于C_(tr)所参考的频谱,其能量频谱分布更接近于C_(100~3150);对比分析11组外窗的交通噪声频谱修正量C_(A)与现行标准的频谱修正量的差异,C_(A)均落于C和C_(tr)参考频谱之间的范围内;C_(A)与C、C_(tr)参考频谱的相关系数R2的值均>0.9且高于C与C_(tr)的相关性,因此C_(A)对城市道路交通噪声频谱修正具有更好的适用性与代表性,研究结果可为临街住宅的隔声降噪工程提供数据参考。

基于模型偏差学习的交通信号自适应优化方法

城市交通信号配时优化是保证交通系统整体运行效率的前提条件。传统基于模型的信号控制方法往往基于历史统计数据,并且底层交通流模型不可避免地存在模型偏差,影响控制方案的科学性及其实际应用效果。考虑模型与数据融合驱动,提出一种基于模型偏差学习的交通信号控制自适应优化方法,以最小化路网行程时间为目标,建立信号控制最优化模型。首先,针对交通流预测模型的模型偏差,引入偏差函数表示预测模型与实际交通流状态间的误差;其次,建立基于径向基函数(RBF)神经网络的偏差函数,结合实际交通流数据对模型偏差进行学习,提高偏差函数的拟合效果;在此基础上,提出考虑模型偏差信息的自适应优化方法,以提高信号控制方法的控制性能。以小型测试路网与实际路网为例进行算例分析,基于SUMO仿真对本文提出的模型偏差学习方法进行验证,考虑不同交通流量条件,与固定配时、模型预测控制进行比较,分析其控制性能指标。结果表明,模型与数据融合驱动的信号控制自适应优化方法能有效提高预测模型的准确性,降低路网行程时间,与基于模型的控制和模型预测控制方法相比路网累积行程时间平均减少了38.3%和25.6%,提升了路网的实际运行效果。最后在宣城实际路网的仿真验证了方法的有效性。

基于OpenStreetMap的城市公交专用道设置优化

为合理设置公交专用道,通过OpenStreetMap(OSM)提取可设置公交专用道的路网,采用Stroke道路表示法将OSM路网与百度路网进行融合,结合百度地图实时交通数据实现交通态势可视化,从而准确直观地识别出公交专用道的设置路段。通过构建公交路阻函数模型,计算设置公交专用道前后的时间效益差,确定公交专用道的设置方案。最后以南昌市部分路网为例,通过SUMO软件仿真结果表明:在青山南路设置公交专用道可以使公交车辆延误降低19.6%;社会车辆延误降低10.8%。实例验证所提出的设置优化方法有利于减少交通延误,为合理设置公交专用道提供支持。

基于交通态势可视化分析的公交专用道布局

交通拥堵问题是困扰城市的普遍难题,科学地规划公交专用道是在城市道路空间资源有限的情况下提高运输效率的有效手段。探讨如何利用交通态势数据和路网信息来规划和评估公交专用道布局问题。首先选取公交专用道布局的研究范围,借助道路交通信息技术,利用交通路况分析与发布平台的大数据,将区域交通态势可视化,做交通路网态势评价,提出该区域的公交专用道布设方案。再从路网整体效益出发,构建以碳排放量最小和系统总出行时间最少为优化目标的多目标优化模型,分析设置公交专用道的效益。最后以南昌市中心某片区为例,选取交通拥堵严重、暂无公交专用道、且满足公交专用道设置条件的路段提出公交专用道布设方案,结果表明设置公交专用道能减少路网中车辆碳排放、改善路段的整体通行效率,减碳平均优化率为4%,时间效益平均提升5%,可知本文提出的优化方法有利于得到合理有效的公交专用道优化方案,为城市交通管理者提供决策依据。

自然驾驶状态下城市地下环道驾驶人心理负荷研究

为探究城市地下环道驾驶人心理负荷特性,组织驾驶人自然驾驶试验,使用生理仪获取自然驾驶状态下驾驶人心电信号数据。以驾驶人心率、心率增长率和心率变异性指标为关键变量,基于因子分析法构建心理负荷量化模型,揭示地下环道平曲线半径、曲线类型、出入口以及熟练程度对驾驶人心理负荷的影响。研究表明:心率指标和心率变异性指标分别与地下环道平曲线半径呈负相关和正相关关系;驾驶人心理负荷与平曲线半径呈负相关,在相同半径条件下,连续曲线场景下的心理负荷显著高于单个曲线场景,且连续曲线间负荷累积作用超过单一曲线半径对驾驶人心理负荷的影响;入口段驾驶人心理负荷比出口段高21.39%;非熟练驾驶人心理负荷比熟练驾驶人高30.75%;建议在城市地下环道出入口和曲率变化区段增设视线诱导设施,设计车速为20~40 km·h^(-1)时,平曲线半径不宜小于30 m。