The impacts of connected vehicle technology on network-wide traffic operation and fuel consumption under various incident scenarios

ABSTRACT

Incidents are a major source of traffic congestion and can lead to long and unpredictable delays, deteriorating traffic operations and adverse environmental impacts. The emergence of connected vehicles and communication technologies has enabled travelers to use real-time traffic information. The ability to exchange traffic information among vehicles has tremendous potential impacts on network performance especially in the case of non-recurrent congestion. To this end, this paper utilizes a microscopic simulation model of traffic in El Paso, Texas to investigate the impacts of incidents on traffic operation and fuel consumption at different market penetration rates (MPR) of connected vehicles. Several scenarios are implemented and tested to determine the impacts of incidents on network performance in an urban area. The scenarios are defined by changing the duration of incidents and the number of lanes closed. This study also shows how communication technology affects network performance in response to congestion. The results of the study demonstrate the potential effectiveness of connected vehicle technology in improving network performance. For an incident with a duration of 900?s and MPR of 80%, total fuel consumption and total travel time decreased by approximately 20%; 26% was observed in network-wide travel time and fuel consumption at 100% MPR.     

Modal shift from road haulage to short sea shipping: a systematic literature review and research directions

ABSTRACT

Modal shift from road haulage to short sea shipping (SSS) has been advocated by authorities and researchers for more than two decades. This paper provides a review of literature on modal shift and pinpoints paths for future research on topics in six categories: (1) factors influencing SSS competitiveness, (2) the policy-oriented perspective, (3) environmental legislation, (4) SSS performance, (5) port characteristics, and (6) the multi-agent perspective. In particular, we propose first, in evaluating the performance of SSS versus road haulage in different trade corridors, three performance-related dimensions – the economic dimension (e.g. external costs), the environmental dimension, and the dimension of service quality – should be considered. Second, researchers should use rich, real-world, numerical data and operational research techniques to identify the relative importance of individual drivers and barriers for a modal shift from road haulage to SSS. Third proposed direction is related to assessing which groups of actors certain policies should target. In doing so, researchers should extend their policy-related focus beyond the European Union, which has long encompassed the major geopolitical scope of research on the modal shift. Fourth, to moderate the adverse impact of environmental legislation on SSS, strategic solutions need to be identified. Fifth, we also suggest that the influence of contingencies, particularly port strikes and cyberattacks, on SSS operations and approaches for managing them should be investigated. Sixth, the economic and financial advantages of coordination and alliance for each transport chain agent need to be evaluated.     

双块式点支撑浮置板环境振动影响研究北大核心

针对钢弹簧浮置板道床结构因采用混凝土短轨枕而难以到达设计减振效果的问题,借鉴高速铁路建设经验,将双块式轨枕与点支撑道床有效结合,研发出适用于城市轨道交通的新型双块式点支撑浮置板道床结构。通过数值模拟和现场试验,对该系统的减振效果进行验证。结果表明:双块式点支撑浮置板道床结构有利于轨底坡的保持,便于轨排的组装,可以改善轮轨受力;车速80~120 km/h时,双块式点支撑浮置板道床结构试验段的减振效果达到14 dB以上,减振效果良好;该系统具有显著的经济和社会效益。     

摩托车平顺性的道路模拟试验研究

运用谐波叠加法建立了C级路面模型,通过模拟迭代将路面不平时间历程转化为激振器的驱动信号,并应用于道路模拟的摩托车平顺性试验测试中。采用两通道轮胎耦合道路模拟试验机对摩托车系统进行了振动试验,分别对驾驶员座垫、脚踏、手把和行李箱位置的振动加速度进行了测试,测试结果表明,行李箱处的振动最大,手把位置和脚踏位置的振动次之,座垫处的振动最小。     

深厚沉积层大直径钢管桩承载特性试验研究

结合某港口工程桩基试验项目,对2组大直径钢管桩进行了竖向承载力静载试验,并通过桩身预埋的应变式钢筋计测试桩身轴力分布,分析了深厚沉积层中大直径钢管桩的轴向承载性状和荷载传递机理。     

汽车钢板弹簧产品技术发展趋势研究

通过对欧洲商用车钢板弹簧产品与国内产品技术对比分析,在平顺性、工作应力、附件选用、产品结构设计和极限应力五个方面进行了详细的技术分析,得出了钢板弹簧产品技术面临高性能、高应力、轻量化及结构异型化的发展趋势的结论。并结合国内钢板弹簧行业的发展现状,为钢板弹簧产品的技术发展指明了一个参考方向。     

提高政府投资监管效率机制研究

政府投资监管是一项重要的政府公共管理职能。该文对提高政府投资监督效率机制作了研究。通过建立职能定位清晰、分工科学合理、协调运转高效的政府投资监管机制,发挥政府投资监管有关各部门的职能作用,提高政府投资监管效率,促进政府投资项目的科学决策和规范管理,提高公共政策的效应和政府投资的效益。     

混凝土预制块铺面接缝渗水特性试验研究

混凝土预制块铺面被广泛应用于城市人行道、小区、公园和景区路面铺装,预制块铺面存在大量不连续接缝,致使其渗水特性与传统的沥青路面和水泥路面有很大不同。针对混凝土预制块铺面接缝的渗水特性开展试验研究,研究接缝材料和接缝宽度对渗水系数的影响,实测不同类型接缝在不同时间段内的渗水量,在此基础上提出预制块铺面的设计渗水系数和渗水量计算方法。通过室内模拟降雨试验研究预制块铺面的排水特性,针对混凝土预制块用于高速公路紧急停车道提出典型的路面结构内部排水方案。     

长大铁路隧道机械化施工配套技术经济分析研究

为研究长大隧道大型机械化施工建造费用确定的方法和途径,通过对隧道施工机械化配套技术研究及实际施工情况的调查与测定,对机械化施工进行工程经济分析研究,核算出隧道在不同围岩条件下的施工机械化配置,在合理的施工组织条件下的经济指标及所需要的工程费用。通过与普通钻爆法对比,长大隧道机械化施工配套能有效地加快施工进度,缩短工期,改善作业环境,保证施工质量,降低安全风险,虽然直接建造费用有小幅度增加,但综合效益显著。