Review of traffic safety evaluation at T-intersections using surrogate safety measures in developing countries context

In recent years, significant research has focused on traffic safety evaluations at unsignalized intersections due to complex and heterogeneous traffic movements as well as driver behaviour at such locations. However, at unsignalized T-intersections, priority traffic rules are less respected, which creates more conflicts. Further, multiple traffic movements such as right turns and through movements with varied driver behaviour results in increases the severity of conflicts. Many research studies have focused on the proactive safety measures in traffic safety evaluations as compared to crash-based analysis. Also, it is observed that Time to Collision (TTC) and Post Encroachment Time (PET) are the predominant types of surrogate safety measures in traffic safety evaluations. From the existing research outcomes, it is understood that these surrogate safety measures may give a better understanding of chain events for crash occurrences, collision mechanisms, and resulting consequences. However, further research is required in order to understand the suitability of such surrogate safety measures based on the complexity of heterogeneous traffic as well as driver behaviour with considerations of turning vehicles, particularly at T-intersections. In this context, this paper critically reviews the recent developments in Surrogate Safety Measures (SSM) and their applications at unsignalized intersections, with a particular focus on the T-intersection. This paper also brings attention to T-intersection safety evaluation with SSM in a developing country context. The outcome of the present study is more useful in the evaluation of traffic safety at T-intersections and suitable safety indicators for the evaluation.     

沃尔沃卡车:突破商用车售后服务瓶颈

随着中国在短短五六年间一跃成为世界前三位的汽车市场,汽车业作为国民经济支柱产业的地位已经获得人们的共识.尤其是商用车市场,持续扩大的市场需求激发了产品品质的整体提升.但是销量的增长并不代表售后服务水平提高,商用车售后服务怎样突破瓶颈,达到世界先进水平,还需要我们认真思考.     

交通运输与物流业、旅游业发展耦合协调度分析——以武汉市为例

研究城市交通与其他系统间的协调性问题具有重要意义。为研究交通运输与物流业、交通运输与旅游业发展的协调程度, 构建反映3个系统发展水平的指标体系, 在此基础上构建耦合协调度模型、分析系统间的耦合协调状况。以武汉市2010-2017年交通运输系统与物流业、旅游业发展为例, 进行综合实证分析。结果显示, 3个系统之间综合评价值总体上均呈现出持续上升发展之势。其中, 交通运输业与物流业的协调耦合度从2010年的0.0841上升至2017年的0.9301, 交通运输业与旅游业的协调耦合度从2010年的0.1197上升至2017年的0.9314, 均经历了从严重失调到高度协调的阶段。研究结果与武汉市实际发展情况一致, 可证明所提方法的有效性。     

Socio-economic costs of road crashes in middle-income countries: Applying a hybrid approach to Kazakhstan

Information about road crash costs is a valuable input for road safety policy making and it is essential for conducting cost-benefit analysis of road safety interventions. This paper presents a methodology for assessing the socio-economic costs of road crashes as well as an estimate of the volume of these costs in Kazakhstan. Five costs components have been taken into account: medical costs, production loss, human costs, vehicle damage and administrative costs. A hybrid methodological approach has been used, which implies that three different types of methods have been applied to capture all costs: the human capital method (production loss), willingness to pay (human costs) and restitution costs method (other components). Input data were retrieved from existing databases from a variety of road safety stakeholders and other organizations. A household survey was conducted to collect additional information, including the willingness to pay for fatal crash risk reductions. Remaining data gaps have been bridged by using data from other countries. The socio-economic costs of road crashes in Kazakhstan are estimated at $6.8 billion in 2012, which corresponds to 3.3% of GDP. Human costs account for 81% of the total costs, vehicle damage for 11% and production loss for 6%. Administrative and medical costs are relatively very small cost components. More than half of the costs is related to injuries, while fatalities account for about a third of the total costs and property damage only accounts for approximately 10%.     

厦门翔安海底隧道过风化深槽施工

 根据厦门翔安海底隧道过风化深槽施工的工程实践经验，介绍了在可能发生灾害性的突泥、突水、塌方和诱发地面塌陷而导致海水下灌等地质灾害的情况下，如何采取超前地质预报、设置防水闸门、超前管棚及全断面帷幕注浆等施工辅助措施，从而保证了过风化深槽施工的顺利进行。     

Defining suitable Safe System projects: The experience of the SaferAfrica project in five African countries

When dealing with road safety in Africa, one should bear in mind that road safety problems need to be seen in their context as the solutions proposed to address them. While it is relevant to consider international good practices, African stakeholders should become owners of the interventions addressing their problems and take the responsibility for developing and implementing the appropriate solutions, taking advantage of suitable technical assistance, if needed. Based on these considerations, in this paper, a presentation is made of the process used in the European research project SaferAfrica to define suitable Safe System projects in Africa. This project aims at supporting policymakers and stakeholders with evidence on critical risk factors, related actions, and good practices drawn from high-quality data and knowledge. In the project, road safety and traffic management capacity reviews at the country level were carried out in five countries (Cameroon, Burkina Faso, Tunisia, Kenya, and South Africa), following the World Bank guidelines. After conducting such a capacity review, these guidelines recommend the preparation and implementation of Safe System projects, “stand-alone, multisector initiatives targeting high-risk corridors and areas, with outcomes large enough to be reliably measured.” In SaferAfrica, this approach aims at facilitating the implementation of Safe System projects in the considered countries, by identifying detailed short-term improvement plans and producing contextualized terms of reference for some interventions per selected country. These interventions are remedial, they address high-priority concerns and demonstrate the viability of high potential gains within current administrative and legislative frameworks. To design interventions suitable to the existing context, the transferability audit tool was adopted within a “participative” process, involving all possible interested parties, from the institutions to NGOs. Results from the process are presented and discussed.     

遵义市子尹路南延线长距离双连拱隧道快速施工技术

为解决双连拱隧道独头掘进不能提前施工中隔墙进而导致正洞无法开挖的问题,子尹路南延线隧道工程提出"三导洞+联络通道"的施工方法,这在国内尚属首次提出和应用。介绍该工法的基本原理,详细阐述其在子尹路南延线隧道工程中的实施过程。得到的主要结论如下:1)通过设置联络通道及组织洞内多次交通转换,使得中隔墙得以提前施工,实现了快速施工;2)通过确定合理施工步序,采用拱架密排对联络通道处加固、加强监测等措施确保了施工过程的安全。     

防汛预案的地位作用和编制原则

防汛预案在防汛法规中具有重要法律地位。历年防汛工作的实践证明防汛预案对推进防汛责任制的落实、防汛工作的规范化建设、以及迅速处置洪涝灾害、减轻灾害损失等方面都发挥着巨大的作用。防汛预案必须根据防汛专业规划、防汛工作设施防御能力和国家规定的防汛标准进行编制 ,做到切实可行 ,并不断修订完善。防汛预案编制完成后 ,还必须依法狠抓贯彻落实 ,才能使防汛预案发挥其应有的作用。     

企业导入逆向物流之考量因素——以纺织业为例

企业为发展经济效益时,在供应链架构中所产生的废弃物,碍於仓管空间的缺乏与处理中心技术之欠缺,逆向物流受到社会各界的广泛关注。为探讨企业导入逆向物流之考量因素,以传统产业——纺织业为例,透过问卷调查之结果,得到重要因素之权重,并透过企业访谈针对产业产品特性及现行逆向物流实施之流程。结果期能让企业在导入逆物流的同时,考量产业特性并重要考量因素投入适当资源,得到完整供应链循环。     

基于Synchro的相位差优化方法研究——以长安街交叉口为例

干道信号协调控制是提高干道通行能力的重要途径.以长安街交叉口为例.在分析数解法优化原理的基础上,剖析数解法存在的缺陷,并提出改进方法.利用Synchro软件进行交通仿真,结果表明,改进后的数解法更加合理有效.     

瘦西湖超大直径盾构隧道施工对周边环境影响分析

大直径曲线盾构隧道中,盾构掘进时盾构对其两侧和拱顶上方的土体作用不同,不同位置土体表现出不同的变形规律。为了保证曲线盾构隧道施工安全进行,并针对变形的差异性提出相应的解决方案,采用现场监测和FLAC 3D数值模拟相结合的方法,对超大直径曲线盾构隧道施工中周边土体变形进行分析,监测项目包括地表沉降、分层沉降、土体深层水平位移。研究结果表明:1)随着隧道掘进,地表沉降呈现反"S"形变形趋势,与3个变形阶段对应,即盾构切口到达时缓慢隆沉,盾构通过时沉降较快,盾尾脱出时沉降趋于稳定;2)横向沉降槽曲线中,掘进时隧道掘进方向曲线内侧沉降量比外侧对称位置沉降更大;3)土体水平位移在隧道掘进方向曲线内侧变形量小于外侧变形量。     

厦门东通道CRD法施工段中隔壁变形分析

针对目前国内采用CRD法修建隧道施工过程中对临时中隔壁的研究很少，结合厦门东通道（翔安）海底隧道现场监控量测数据，对施工过程中中隔壁的变形及其规律进行了分析，这为实现隧道的安全施工提供了依据，也为今后的相关工程积累了经验。     

成都地铁河中桥梁桩基托换施工技术

成都地铁2号线春熙路站-东门大桥站区间盾构隧道左线自东门大桥桩基中穿过,为保证盾构顺利通过并确保桥梁安全,采用托台换桩法对侵入隧道桩基进行托换处理。施工中采用河中围堰、帷幕注浆、降水、人工挖孔和静态爆破等辅助方法有效控制了地下水的影响和桥台沉降,确保了桥梁、管线安全及整个托换施工的顺利实施。     

城市居民使用共享单车意向研究——以合肥为例

为了探究共享单车使用意向的影响因素和因素间的作用关系,基于计划行为理论(TPB)构建了关于态度、主观规范、感知愉悦、灵活便捷和行为意向等潜变量的计划行为理论扩展模型.通过对问卷调查数据的信度和效度的分析,构建了共享单车使用意向的结构方程模型(SEM),得到各影响因素间的关系路径.结果表明,TPB理论可以很好地解释居民使用共享单车的行为意向,在共享单车的使用意向影响因素中,主观规范的影响最为显著,态度居其次,再次是感知愉悦,而灵活便捷对行为意向的影响作用相对较弱.     

从一起火灾事故应急救援过程谈在建隧道应急设施的设置

以一起在建特长隧道火灾事故为例,分析事故救援过程中存在的问题,认为在建长大隧道灭火、通讯、逃生、救援等应急设施的设置方案和对应急通道、通风和演练的要求,对在建隧道的火灾应急准备有现实指导作用。     

Characteristics of operating mode distributions of light duty vehicles by road type,average speed,and driver type for estimating on-road emissions: Case study of Beijing

Abstract

Researchers have collected extensive vehicle activity data in Beijing using GPS and attempted to develop a comprehensive database of facility- and speed-specific operating mode (OpMode) distributions of various vehicle types for estimating on-road vehicle emissions. This study developed the specific OpMode distributions of light duty vehicles (LDVs) for both restricted access and unrestricted access road types at various average speeds for characteristic analysis. (1) Strong patterns are found in the variations in OpMode distributions with the increase in the average speed: the time fraction of Decelerating/Braking remains less than 7%. The fraction of Idling decreases dramatically from 95% to 0%, while the fraction of Cruising/Accelerating increases from 2% to 94%. The fraction of Coasting increases to 28% and then decreases. (2) The time fractions for restricted access and unrestricted access are significantly different at the same average speeds, especially in Operating Modes #0, #1, #11, #12, #13, #14, #21, and #22, possibly causing an error of 20% in the emissions estimations. (3) Taxis show different OpMode distributions than those for private cars in the operating modes of Decelerating/Braking, Idling, and high-VSP modes, especially at low average speeds. The differences are derived from the more skillful driving behaviors of taxi drivers and may cause an estimation error of over 10%. Thus, the activities of taxis and private cars should be modeled separately for on-road emissions estimations.     

宝马4S维修站经典案例专辑（七）——宝马GT535i乘员保护系统故障检修1例

一辆2010年3月由德国宝马汽车集团丁格芬工厂生产的宝马535i,其车型系列为F07,车身类型为GT,底盘号为C530178,搭载N55发动机,已行驶1590 km。     

超前地质预报在连云港后云台山隧道围岩分级中的应用

针对连云港后云台山隧道可能会出现的各种地质灾害,为了在施工前期探明掌子面前方的复杂地质情况并进行稳定性预测分析,提出应坚持从工程实际出发、合理选择、综合使用有效的方法和手段,制定背景项目的超前地质预报工作方案。其能充分发挥各种方法和手段的特长,对隧道围岩等级进行预测评定,为隧道围岩的稳定和施工安全提供有力保证。并经实践证明,采用综合超前地质预报方法预测围岩等级,总体预报准确率达到80%以上。     

Investigating performance of a novel safety measure for assessing potential rear-end collisions: An insight representing a scenario in developing nation

Road safety is one of the major concerns in the ever-growing traffic network. In addressing this, surrogate safety measures play a critical role in identifying collision instincts. Besides the added advantage of quantifying collision instincts in advance, surrogate safety measures have their limitations. For example, in some instances, those measures tend to show erroneous results. In this paper, a new surrogate safety measure Instant Heeding Time (IHT), is presented based on follower vehicle attention in the traffic streams. This new measure is integrated with a distance gap and the vehicles' speeds to assess probable rear-end collisions. Further, along with other safety measures, the developed safety framework is tested over a study section, with the help of trajectory datasets at three traffic flow conditions (free flow, capacity, and congested) under prevailing heterogeneous (mixed) traffic conditions. Based on the safety framework, it is observed that, in the case of free flow and capacity conditions, 23 and 55 probable rear-end collisions points are detected. At the congested conditions, no rear-end collision points are observed. Further, smaller vehicles in the traffic stream are associated with a higher number of rear-end collision instincts than other vehicle categories. The conceptualized safety framework can be applied on a real-time basis for monitoring the safety measures for vehicles in a mixed traffic stream.