Evaluation of Merge Control Strategies at Interstate Work Zones under Peak and Off-Peak Traffic Conditions

Maintenance and rehabilitation projects of interstate facilities typically mandate lane closures. Lane closures require merging maneuvers that often result in reduced speeds and traffic bottlenecks. Work zone impacts on traffic operations are magnified when project durations are extended. Conventionally, work zone traffic control plans are developed to address work zone impacts. This study evaluated various merge control strategies at interstate work zones peak and off-peak traffic conditions and summarized related impacts. A comprehensive microscopic simulation model was developed in full consideration of driver/vehicle behavior at work zones. The analysis of simulation results revealed that merge control strategies, when implemented during peak and off-peak conditions, can preserve the level of service and provide favorable mobility, safety, and environmental impacts. In addition, results indicate that transportation agencies’ practice of scheduling work zone activities during the off-peak may not be the most optimum approach. Overall, the findings of this study highlight the need for evaluation of work zone scheduling practices in full consideration of agency, user, and project costs.

Assessing Work Zone Traffic Control Options for 3-to-1 Lane Closures

The presence of highway construction zones hinders mobility and affects traffic operations. A 2002 study by Wunderlich & Hardesty reported that nearly 20% of the National Highway System roads have scheduled construction work during the peak construction season. Additionally, approximately 24% of non-recurring delays on freeways are caused by work zones. To minimize time lost by travelers due to work zone induced traffic congestion, it is important to efficiently plan temporary traffic control (TTC) at work zones. Earlier research conducted by Sisiopiku & Ramadan, 2017 confirms that the majority of State Departments of Transportation currently rely on their earlier experience when planning for work zones, rather than consider operational and safety impacts. Using a study corridor in Birmingham, Alabama as a test bed, this study investigated the operational impacts of TTC options for work zones with 3-to-1 lane drop configuration using traffic data collected from the Alabama Department of Transportation. The VISSIM simulation platform was used to conduct the experiments. The experimental design considered two TTC strategies (i.e., static late and early merge) under 3-to-1 lane drop configuration for work-space length of 500 ft for long- and short-term lane closures. The study concluded that the 3-to-1 lane-drop configuration should not be scheduled for long-term duration. Maintenance work can be scheduled from midnight to early morning and under the 3-to-1 lane closure scenario the performance of early and late merge traffic control is similar. Overall, this study used simulation modeling to compare the effectiveness of two traffic control strategies at work zones on the basis of different performance measures. The results provide information about the impact of each control strategy on density, speed, travel time etc. They also help determine what time of the day is best for lane closings in order to reduce adverse impacts from capacity reduction. Thus, the findings are expected to provide valuable guidance for agencies responsible for planning, design, and operations of work zones in the future.

Traffic Calming in Historic District Conservation

The Historic Conservation District(HCD) is an important target for urban heritage protection in China. The spatial characteristics of its road system,formed before the appearance of automobile,do not adapt to the car traffic. In the context of very rapid motorization in Chinese cities,the increase in car traffic brings an inevitable trouble for the protection of HCDs. Road widening and pedestrianization are two popular solutions to this problem in current practices; however,both of them may lead to negative consequences. Inspired by the development of Zone 30 in European cities,this paper firstly cleared up first some misunderstandings of the concept of traffic calming,then taking the inner city of Paris as an example,explained how traffic calming measures can be implemented in HCDs and what effects will be generated. Finally,it discussed the possible application of traffic calming measures in HCDs projects in China and pointed out the specific situations of Chinese cities to which the planners should pay more attention.

Movement of Autonomous Vehicles in Work Zone Using New Pavement Marking: A New Approach

The autonomous vehicles are the future of mobility across the globe and are expected to touch the lives of every person of all ages. But this comes with certain challenges regarding safety, reliability, cost, legal framework, regulations, etc. however, of all the concern safety and reliability are of utmost importance for researchers and engineers. The current research is focused on the movement of the autonomous vehicle in the work zone. The work zone is one of the most challenging areas for the autonomous vehicle to drive from. This is because the work zones are very dynamic, and all the construction activities are specific to the site condition and cannot always be predefined. The study provides a concept of how pavement marking can be used for smooth movement through the complicated work zone. In this study, various pavement marking signs have been designed as a concept considering the standard colors and striping width being used in the Manual of Uniform Traffic control device (MUTCD). The study assumes that the movement of the autonomous vehicle will not be exclusive and that it will move with the driver driven vehicle. It is expected that autonomous vehicles will require special pavement marking and signage for smooth movement through the work zone. These pavement marking and signage will eventually become part of standard Traffic Control Plans (TCP) and Maintenance of Traffic Plans (MOT). The research aims to study the current research being done in this area and technology being used for detecting various pavement markings and signages.

公路隧道入口区域驾驶人吸睛效应综合评价

为全面和系统评价公路隧道入口区域视觉吸引对驾驶人吸睛效应视觉表现的影响,本文招募30名被试开展自然驾驶实验,采集驾驶人在公路隧道入口区域不同视觉吸引条件下的眼动数据,基于因子分析法选取驾驶人吸睛效应敏感评价指标,并分别构建线性混合效应模型和数据包络分析模型,识别和探究公路隧道入口区域视觉吸引对驾驶人吸睛效应视觉表现的影响特征和作用机理。结果表明:因子分析结果显示,驾驶人吸睛效应敏感视觉指标为注视持续时间、瞳孔直径、扫视持续时间和扫视幅度;公路隧道入口区域不同视觉吸引条件对驾驶人吸睛效应的视觉表现和综合效率有显著影响,且受驾驶人年龄和驾驶经验的个体特质因素影响显著,而性别因素对其没有显著性影响;视觉吸引的存在均会不同程度地损害驾驶人的正常视觉绩效,降低其合理有效性;提示标语视觉吸引条件下,驾驶人的视觉注意水平最差,视觉认知负荷程度最高,吸睛效应的负面影响最大,广告牌条件次之。

Dashboards for Monitoring Congestion and Crashes in Interstate Work Zones

Work zones present challenges to safety and mobility that require agencies to balance limited resources with vital traffic management activities. Extensive literature exists regarding the impact of congestion and recommendations for work zone design to provide safe and efficient traffic operations. However, it is often infeasible or unsafe to inspect every work zone within an agency’s jurisdiction, so it is important to obtain operational feedback regarding congestion and crashes in work zones to prioritize inspection activities. This paper outlines the use of connected vehicle speed data and crash report data to identify operational performance problems in work zones. This is a way to provide feedback to queuing models used to design maintenance-of-traffic (MOT) plans. A weekly work zone report and dashboards were developed for use by the Indiana Department of Transportation (INDOT) for the purpose of assessing and improving both mobility and safety in work zones. The study has developed a mile-hours of congestion graph, frequency of speed delta heat map, congestion profile graph, and the Route Builder interactive application to comprehensively visualize work zone performance. This weekly report provides a mechanism for agency staff to maintain situational awareness of which work zones were most challenging for queues and during what periods those were likely to occur. In one case study, the reports were used to identify and mitigate operational performance problems in a work zone within 4 weeks, reducing congestion and crash rates. The integration of these data provided project managers with quantitative information about traffic mobility and performance of work zones for informed decision-making during the construction season.

基于Topsis改进因子分析的公路隧道入口段视觉负荷研究

为探究直线公路隧道入口段驾驶者的视觉负荷,首先,通过实车试验采集5种视觉指标,采用Topsis改进因子分析法建立视觉负荷评价模型;然后,分析不同时间及位置下视觉负荷的变化特征,基于构建的视觉负荷曲线提出行车舒适评价标准,并运用已发表数据验证构建负荷模型的泛化能力;最后,通过敏感度分析探究视觉指标对视觉负荷的影响程度。结果表明:当驾驶者位于距洞口-13~55 m(12:00)、-10~49 m(15:00)时,视觉负荷超过临界值(0.906),驾驶者的行车舒适度和安全性极低;洞口驾驶者的视觉负荷值和接近度远大于洞内和洞外;18:00的视觉负荷和接近度远低于12:00和15:00。视觉指标的敏感度参数从大到小依次为注视时间、瞳孔面积、注视次数、扫视幅度、扫视速度。

城市道路网联混驾车辆分阶段动态轨迹控制方法

随着城市的进步和不断发展,智能驾驶车辆逐渐代替路段中的部分人工驾驶车辆,但在未来较长时间内人工驾驶车辆并不会被完全取代,此时出现网联车与人工驾驶车辆的混驾环境,即目前以及未来时间内我们面临的驾驶环境。网联车与人工驾驶车辆驾驶行为在路段内相互干扰,造成混合车流行驶效率低下。为减弱2种车辆间的相互作用,提出一种分离混驾环境下网联车和人工驾驶车辆的分阶段动态车道引导算法(dynamic lane guidance algorithm for separating CAVs and HDVs in mixed traffic environment,SCHME)。通过该算法分离在交叉口上游路段的混合流车辆集合,调整智能驾驶车辆的行驶路线并进行实时动态更新,在满足运动学约束收敛的条件下,人工驾驶车辆根据网联车的动态路线进行相应调整,实现在每辆车广义安全损失成本最小的情况下提高路段内混驾环境下车辆运行效率。通过MATLAB模拟车辆在进入交叉口前的车辆运行状态,结果表明,SCHME算法可在广义安全损失成本最小的情况下提高路段内平均车辆通行效率(17.29%),同时当车辆优化数组越大,车辆集合距离交叉口越远时,智能驾驶车辆渗透率越低,每辆车的道路广义安全损失成本越低。

基于元胞自动机的城市快速路长距离交织区运行仿真

为了研究城市快速路长距离交织区对交通流运行特性的影响,建立多车道元胞自动机模型.根据长距离交织区内不同位置的换道车辆,考虑其各自换道行为和换道需求强度,引入3种不同换道规则,并对长距离交织区进行分段设定.基于动态安全间距、车流管理策略双重要素,构建不同管理策略下的多车道元胞模型.仿真结果表明,长距离交织区内的强制性驶出换道行为容易引发局部拥堵,形成出入口瓶颈.虽然双虚线型策略能够提供更多驶出车辆换道机会,但随着占有率的增加,这种优势逐渐减弱,相比之下,虚实线型策略更加合理.虚实线型策略-主路优先机制保证主路驶出车辆换道路权,不可避免会牺牲部分辅路通行效率.考虑到辅路的间断交通流特性,虚实线型策略1(先出后入)仍具备一定的实施价值.

城市连续隧道交织区主线交织车辆换道点选择行为研究

基于城市连续隧道交织区分析主线交织车辆换道点选择行为,以实地采集的车行轨迹数据为基础,利用随机森林模型分析主线车辆换道点选择行为特征及影响行为决策的影响因素,而后分别采用支持向量机模型与随机森林模型进行换道点选择行为决策建模和对比分析。研究结果表明:影响主线交织车辆换道点选择的主要因素为目标车辆状态以及本车道的后车状态,且经特征筛选之后建立换道决策模型的精度更高,其中支持向量机模型可以较好的刻画换道行为,模型的预测精度不低于85%。研究成果有助于在仿真模型中更准确描述换道点选择行为,同时为城市连续隧道交织区的优化和辅助驾驶策略制定提供支撑。

精细化治理背景下的交通限行区分级管控合理性评估与优化——以杭州市为例

合理地划定限行区域,辅之以差异化的交通需求管理政策能够有效缓解城市拥堵、精准提升城市交通治理水平。以实时交通拥堵指数、OSM路网数据、公交线路和站点数据为研究数据,识别杭州市分级限行区内的拥堵区分布,分析拥堵区交通供给特征,在此基础上划分拥堵区类型并提出分类管控优化策略。研究发现,杭州市限行区分级较为合理,对浙A及区域号牌限行的拥堵区路网密度及其等级配置合理,公共交通供给略有错位与不足;对外地车辆限行的拥堵区路网供给不足,公交供给水平相对较高,但在精细尺度上存在交通供给要素的错位与替代性公共交通不足的问题;根据交通供给特征及限行政策将拥堵区划分为片区式、飞地式和节点式拥堵区,分别提出实施拥堵收费、优化路网结构、提高微循环能力、增设公交线路串点成线及引导公交出行等策略,以期为大城市交通精细化治理提供借鉴。

不同视线诱导系统下高速公路隧道入口减速行为试验研究

为分析驾驶人在隧道入口区域的减速行为特征,并定量评价不同视线诱导设施的调节作用,开展模拟试验,基于日间自由流状态构建场景1(行业标准、对照组)、场景2(2.5 m立面标记)、场景3(环形立面标记)、场景4(多层次视线诱导系统)4组试验场景,采用开始减速位置、减速度变化率、油门开度变化率等指标进行分析。试验结果如下:1)驾驶人速度变化呈现“平稳—下降—较平稳”趋势;2)在行业标准下开始减速位置较近,导致需采取较大减速度、较少减速阶段实现车速下降,行车舒适度低于、操纵危险度大于其他场景;3)2.5 m立面标记与环形立面标记均能使驾驶人提前辨识洞门,行车舒适区间占比有所提升;4)多层视线诱导系统表现最优,开始减速位置提前65%,行车舒适区间提升最大(13.1%),且其采用的控制油门减速策略,平均油门开度最大(0.095)、油门操纵危险度最小(0.13),是入口区域较适宜的减速模式。试验结果表明:隧道入口洞门采用环形立面标记、增设多层次视线诱导系统有利于驾驶人早发现、早减速、缓减速,能显著提升隧道入口区域行驶安全性与舒适性。

借用对向车道通行的高速公路施工控制区梯级限速研究

【目的】为使车辆平稳快速地通过借用对向车道通行的高速公路施工控制区,对施工控制区梯级限速方案进行了研究。【方法】首先,采集并分析不同施工控制区断面交通流速和车头时距变化;其次,根据车辆轨迹特征计算末级限速值,基于车辆减速运动特征和驾驶人注视特点制定施工控制区梯级限速方案;最后,构建驾驶模拟实验场景,通过安全与效率协调优化的评价指标对所建立的限速方案进行评价。【结果】结果表明:中分带开口区平均车速和车头时距最小。当中分带开口长度为70 m的两车道时,形成以40 km/h为最终限速值、以20 km/h为降速幅值、以过渡区起点上游50 m为最终限速标志位置的变间距高速公路施工控制区限速系统。【结论】驾驶模拟实验表明,同《公路养护安全作业规程》(JTG H30—2015)中的两级限速方案相比,所建立的梯级限速方案可使施工控制区综合效率指数提高9.15%,综合安全指数提高27.62%。

城市道路交通应对超标降雨的策略--以郑州“7·20”特大暴雨为例

城市道路是应急救援的重要载体,有效降低超标降雨带来的风险对于韧性城市建设至关重要。综合考虑降雨量、道路积水深度、最大允许退水时间,确定超标降雨的交通风险边界条件。基于郑州“7·20”特大暴雨的道路受灾状况、交通运行情况,分析超标降雨情况下的道路风险区,指出传统平坦低洼叠加高路基区域,城市易涝区叠加交通拥堵、高架快速路匝道等区域的灾时风险性较高。然后,从构建特级应急通道网络、完善应急疏散方案、道路行泄通道精细化设计等方面提出超标降雨情况下城市道路交通应急响应策略。最后指出,面临超标降雨等极端天气时城市道路交通应从顶层规划、精细化设计、应急管理等多环节着手,提高城市应对超标降雨的综合防灾能力。

基于改进K-means算法的通勤交通小区识别

通勤是具有周期性和稳定性的城市居民出行行为,是城市发展规划和公共交通管理的重要研究内容。出租车GPS(Global Position System,全球定位系统)轨迹数据在一定程度上反映了城市交通状况和市民出行模式。针对出租车区域性通勤模式识别问题,本文提出一种基于改进K-means算法的通勤交通小区识别方法。该方法主要包括3个步骤:划分交通小区、生成交通小区之间的流量转移矩阵和识别通勤交通小区对。参考现有的交通小区划分方法,本文提出一种基于细粒度单元的自下而上的交通小区划分方法。在通勤交通小区对识别模型中,以高峰时段的流量及其离散系数作为输入特征,基于改进K-means算法识别通勤交通小区对。最后,基于重庆市出租车GPS数据集进行实验验证,结果表明该方法效果显著。

基于交通模型的临空经济区道路交通运行评价

依托航空枢纽和综合交通运输体系,临空经济区逐渐发展为现代服务业、高新技术及高端物流等高质量产业聚集区,促进了地方经济增长。文章在定性分析临空经济区交通运行特征的基础上,以北京大兴国际机场临空经济区为例,应用四阶段法搭建交通模型定量分析,使用TransCAD软件直观展示其道路交通运行情况,提出交通改善措施并证明其有效性。所采用的方法对临空经济区交通规划具有一定的指导价值。

基于服务分区的灵活型公交路径优化方法研究

面对不断增长的乘客需求以及不断扩大的服务范围,需要利用更为高效的区域调度方法解决灵活型公交车辆的路径规划问题。文章针对大规模路网下灵活型公交系统的运营特性,考虑国内封闭式小区路网结构和乘客离散需求分布的特性,构建了基于服务分区的二阶段灵活型公交系统路径优化方法,协同规划服务子区之间及其内部车辆服务路径。同时,提出了强制式、半强制式、灵活式3种路径优化策略,用于校验不同策略下的模型目标值和求解效率。结果表明:服务子区的划分符合客流的时空集聚特征,能够兼顾路径规划的灵活度和乘客需求响应的效率,可应用于求解大规模路网下灵活型公交路径规划设计问题。

城市快速路出口匝道至平面交叉口段治堵的研究

由于交通量的增长和变化,城市快速路出口匝道至平面交叉口段常常成为城市道路上的堵点。针对此类问题,本文分析了产生拥堵的原因,提出治理拥堵的方法,并根据交通工程理论,采用通行能力分析方法,验证快速路出口匝道连接段和下游交叉口改造方案的合理性。快速路出口匝道连接段的治堵,主要使下游交叉口的通行能力大于上游路段的通行能力,连接段中的交织区段长度和排队长度满足使用需求。

基于SUMO软件的公路作业区行车风险仿真分析

文章基于SUMO仿真软件,参照《公路养护安全作业规程》(JTG H30—2015)关于作业区各个区域长度的设定要求,在SUMO中构建仿真环境。试验工况为:封闭右侧单车道。结合实际工况,交通量和大车比例均分为三种情况,采用TTC和DRAC作为评价指标。实验结果表明,在任意工况和任意交通量条件下,车辆进入上游过渡区所形成的“TTC风险墙”、“DRAC风险墙”位置均随着大车比例的上升而提前,其相应厚度也同时增加。

成都市低排放区限行措施方案研究

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