山区高速公路桥隧连接段直立高陡边坡防护

本文主要高以山区高速公路桥隧连接段直立高陡边坡防护施工技术方案的论证及比选,桥隧连接段的位置大多都所处地形地貌与地质状况相对比较薄弱环节,位于这种地形位置的边坡防护要求较高,且要满足该类型边坡防护的效果。根据工程实际因素,需要进一步加强和深化高陡坡隧道洞口与桥梁相接位置的安全防护勘察工作,经现场勘察及几种防护方案的必选与论证,试图从山区高速公路桥隧连接段直立高陡边坡防护方案优化设计的角度降低防护施工难度及成本。鉴于桥隧连接段及隧道洞口现状直立高陡边坡整体基本处于稳定状态,加接延长隧道洞口明洞工程,并采用SNS主洞防护网与被动防护网相结合的防护方案合理可行,该防护方案的施工工艺简单,易操作,施工成本与施工安全风险低。     

桥隧之间柔性短路基段变整体刚性路面段的设计与施工

针对宝天高速公路桥隧之间柔性短路基段可能潜的弊端及隐患阐述,取消传统的桥头搭板、短路基段和隧道混凝上过渡板的桥隧连接方式,改设钢筋混凝土厚整体式刚性路面,使之刚性过渡一致,衔接自然合理,实现行车平顺舒适,减少运营维护。     

山区高速公路桥隧连接工程关键性技术研究

为提高山区高速公路建设总体质量与效率,结合山区高速公路桥隧连接工程的类型与特点,对桥隧连接工程的现存问题、施工类型、施工特性进行分析,提出山区高速公路桥隧连接工程安全运行维护措施,以期提升我国山区高速公路桥隧连接工程关键性技术水平,促进我国山区经济发展。     

针对西南山区高地震烈度区复杂环境，如何建设桥隧安全监测系统？

正在我国西部艰险山区,公路桥梁安全运营所面临的主要风险,除了运营荷载与结构抗力之间的矛盾外,还要面对复杂恶劣的地质地形和水文气候条件带来的灾害风险。怎样通过监测手段,强化山区桥隧结构风险辨识,细化分析评估?保障中国山区桥梁与隧道结构安全,看看专家怎么说……     

山区桥梁建设期多因素风险评估方法研究

文章以贺州至巴马高速公路(都安至巴马段)桥梁工程建设项目为例,分析了山区桥梁工程建设过程中存在的风险因素,并对风险因素的评估方法进行了研究,以期为我国山区桥梁工程建设过程中的风险因素管理提供借鉴。     

山区公路行车视距分析

驾驶员应有足够的视距来判断车辆前方发生的变化,以便采取相应措施确保车辆安全行驶。从山区公路交通流特点和事故成因出发,对平面视距和纵面视距的行车安全性进行了分析,同时从保障行车安全角度总结了行车视距设置应考虑的影响因素,对山区公路路线设计起到一定的指导作用。     

山区公路路基翻浆成因及预防措施研究

为保证山区路面结构的稳定性和行车安全性,对山区公路典型病害——路基翻浆进行研究,分析路基翻浆产生的原因及主要影响因素,并详细介绍山区公路路基翻浆的相关处理方法及预防措施,以期保证公路路基质量,延长公路使用寿命,提高山区公路建设和管理水平。     

基于ANP与模糊理论的寒区隧道冻害风险评估与管理研究

冻害风险是寒区隧道工程建设中的常见灾害,其影响因素复杂,不确定因素较多。文章在广泛调研基础上,结合基于Likert量表的问卷调查建立了冻害风险评价指标体系,利用ANP综合分析各因素之间的相互影响度,计算出二级指标的整体权重,找出主要风险源;再运用模糊评价法分析处理专家评价意见,结合整体权重计算出冻害风险综合评价分值。昆仑山隧道实例证明,该体系具有针对性、客观性和可行性,可有效识别冻害风险影响因素;利用ANP与模糊综合评价可辨识出主要风险源并给出量化风险指标,可为实现有效的风险管理提供理论依据。     

山区高速公路桥隧毗邻项目群施工管理绩效评价研究

山区高速公路进程的加快,导致桥隧毗邻项目群施工备受关注。为提高桥隧毗邻项目群绩效管理水平,从而实现整个工程项目的集体效益合理化,以介绍桥隧毗邻项目群施工管理绩效评价程序为出发点,详细论述了绩效考评的具体内容、考核时间及作用,并以此提出改善桥隧毗邻项目群施工管理绩效的方法,以期为相关施工单位提供参考,促进工程的顺利开展。     

隆林-百色高速公路桥梁设计探讨

广西隆林-百色高速公路是一条典型的山区高速公路,具有地形地质条件复杂、桥隧比例较高、施工难度大的特点。文章结合隆林-百色高速公路项目施工设计图的情况,提出了山区高速公路桥梁设计的要求,并对几个设计典型问题进行了初步的探讨,为山区高速公路桥梁设计提供参考。     

Real-time crash prediction for expressway weaving segments

Weaving segments are potential recurrent bottlenecks which affect the efficiency and safety of expressways during peak hours. Meanwhile, they are one of the most complicated segments, since on- and off-ramp traffic merges, diverges and weaves in the limited space. One effective way to improve the safety of weaving segments is to study crash likelihood using real-time crash data with the objective of, identifying hazardous conditions and reducing the risk of crashes by Intelligent Transportation Systems (ITS) traffic control. This study presents a multilevel Bayesian logistic regression model for crashes at expressway weaving segments using crash, geometric, Microwave Vehicle Detection System (MVDS) and weather data. The results show that the mainline speed at the beginning of the weaving segments, the speed difference between the beginning and the end of weaving segment, logarithm of volume have significant impacts on the crash risk of the following 5–10 min for weaving segments. The configuration is also an important factor. Weaving segment, in which there is no need for on- or off-ramp traffic to change lane, is with high crash risk because it has more traffic interactions and higher speed differences between weaving and non-weaving traffic. Meanwhile, maximum length, which measures the distance at which weaving turbulence no longer has impact, is found to be positively related to the crash risk at the 95% confidence interval. In addition to traffic and geometric factors, wet pavement surface condition significantly increases the crash ratio by 77%. The proposed model along with ITS, e.g., ramp metering, Dynamic Message Sign (DMS), and high friction surface treatment can be used to enhance the safety of weaving segments in real-time.     

高速公路改扩建中车行天桥的拆除施工及安全管控研究

为最大限度降低高速公路改扩建工程非封闭路段原有上跨车行天桥拆除施工对车流通行的影响,并确保施工与交通安全,本文以成乐高速公路扩建试验段的5座旧桥拆除工程为例,针对现有施工技术对拆除作业及交通运行可能带来的风险因素,研究提出了分批次统一破碎拆除的施工方法和安全管控方案,通过合理的施工组织方案和施工工艺、全面的安全管控措施解决了破碎拆除法中可能出现的安全及环保问题。     

An optimal variable speed limits system to ameliorate traffic safety risk

Active Traffic Management (ATM) systems have been emerging in recent years in the US and Europe. They provide control strategies to improve traffic flow and reduce congestion on freeways. This study investigates the feasibility of utilizing a Variable Speed Limits (VSL) system, one key part of ATM, to improve traffic safety on freeways. A proactive traffic safety improvement VSL control algorithm is proposed. First, an extension of the METANET (METANET: A macroscopic simulation program for motorway networks) traffic flow model is employed to analyze VSL’s impact on traffic flow. Then, a real-time crash risk evaluation model is estimated for the purpose of quantifying crash risk. Finally, optimal VSL control strategies are achieved by employing an optimization technique to minimize the total crash risk along the VSL implementation corridor. Constraints are setup to limit the increase of average travel time and the differences of the posted speed limits temporarily and spatially. This novel VSL control algorithm can proactively reduce crash risk and therefore improve traffic safety. The proposed VSL control algorithm is implemented and tested for a mountainous freeway bottleneck area through the micro-simulation software VISSIM. Safety impacts of the VSL system are quantified as crash risk improvements and speed homogeneity improvements. Moreover, three different driver compliance levels are modeled in VISSIM to monitor the sensitivity of VSL effects on driver compliance. Conclusions demonstrated that the proposed VSL system could improve traffic safety by decreasing crash risk and enhancing speed homogeneity under both the high and moderate compliance levels; while the VSL system fails to significantly enhance traffic safety under the low compliance scenario. Finally, future implementation suggestions of the VSL control strategies and related research topics are also discussed.     

Safety outcomes of internationalization of domestic road haulage: a review of the literature

Abstract

The European Union (EU) promotes gradual lifting of restrictions on foreign hauliers involved in domestic road transport of goods (cabotage), and a major deregulation was scheduled in 2014. Due to complaints from several member states facing competition from new EU-countries with lower labour costs, this process was postponed until 2015. An important aspect related to such a deregulatory reform includes potential consequences for transport safety and accident risk factors. The main aims of the current paper are therefore to examine the potential transport safety outcomes of increasing internationalization of domestic road haulage, and to examine potential accident risk factors of foreign hauliers. This is done by reviewing the research literature. This paper shows that the heavy goods vehicle (HGV) accident risk varies with a factor of up to 10 in European countries, and that the accident risk of foreign HGVs is approximately two times higher than that of domestic HGVs in the studied European countries. The paper points to several risk factors and concludes that better data on accident risk and risk factors must be gathered in order to enable European authorities to correctly analyse and respond to this important traffic safety challenge.     

非灯控交叉口交通安全状况评价

非灯控交叉口是交通流中的节点,对非灯控交叉口的交通安全状况进行评价具有导向性意义。文章针对交叉口管控存在的问题,提出了交通安全状况评价原则和主要方法,阐述了非灯控交叉口交通安全的影响因素,并通过对沈阳市刘家窑十字交叉口进行交通安全状况评价,提出了具体的交叉口交通安全改善措施,以提高非灯控交叉口的交通安全性。     

Safer signalized junction design and self-optimizing control

The UK Transport Research Laboratory has long had a Worldwide reputation for contributions to the field of traffic signal control, especially as originators of the TRANSYT and SCOOT signal coordination methods. This article describes some less widely known work. Accident risk at urban junctions and on road links between them is related to a wide variety of factors including: traffic and pedestrian flows, signal control parameters, geometry, and other layout features. Comprehensive studies have derived, and are continuing to derive, quantitative risk relationships for use in off-line software. Those for individual signalized cross-roads have already been incorporated in the TRL's program OSCADY to assist junction design. Now, an area-wide safety model incorporating the CONTRAM traffic assignment program is being actively developed to provide a tool for evaluation of network traffic management schemes. For on-line signal control at individual junctions, the MOVA system has been developed to provide a delay-minimizing or capacity-maximizing control logic as appropriate. ‘Before and after’ comparisons with the UK's previous fully vehicle-actuated signal system are presented, including both delay and safety aspects.     

Assessing the impact of reduced visibility on traffic crash risk using microscopic data and surrogate safety measures

Due to the difficulty of obtaining accurate real-time visibility and vehicle based traffic data at the same time, there are only few research studies that addressed the impact of reduced visibility on traffic crash risk. This research was conducted based on a new visibility detection system by mounting visibility sensor arrays combined with adaptive learning modules to provide more accurate visibility detections. The vehicle-based detector, Wavetronix SmartSensor HD, was installed at the same place to collect traffic data. Reduced visibility due to fog were selected and analyzed by comparing them with clear cases to identify the differences based on several surrogate measures of safety under different visibility classes. Moreover, vehicles were divided into different types and the vehicles in different lanes were compared in order to identify whether the impact of reduced visibility due to fog on traffic crash risk varies depending on vehicle types and lanes. Log-Inverse Gaussian regression modeling was then applied to explore the relationship between time to collision and visibility together with other traffic parameters. Based on the accurate visibility and traffic data collected by the new visibility and traffic detection system, it was concluded that reduced visibility would significantly increase the traffic crash risk especially rear-end crashes and the impact on crash risk was different for different vehicle types and for different lanes. The results would be helpful to understand the change in traffic crash risk and crash contributing factors under fog conditions. We suggest implementing the algorithms in real-time and augmenting it with ITS measures such as VSL and DMS to reduce crash risk.     

道路环境对交通安全的影响及对策

交通安全,涉及到人、车以及道路和环境等很多因素。近年来,因为各种原因使得有关单位以及人员将更多的将精力放在人、车、道路这几个因素上,对道路交通环境没有过多的考虑和研究。深入研究道路交通环境,有利于道路交通的安全,文章通过对其的研究和分析,得出有关道路交通环境对交通安全的影响和解决措施,对于防止道路交通安全事故具有重要意义。同时为人们的生命财产的安全提供保障、对构建社会主义和谐社会具有很大帮助。     

公路隧道交通安全措施探索

保障公路隧道的交通安全不仅事关隧道内司乘人员的生命安全,对隧道本身的结构安全同样有很大的影响。从公路隧道的总体设计、交通工程设施、防火、隧道内装、洞口增减光设施、火灾的预防与救援、隧道的运营管理、宣传教育和交通法规等多方面对影响公路隧道交通安全的因素和相关措施进行了探讨,旨在为公路隧道交通安全措施的研究提供一些思路。     

Modeling the effect of electric vehicle adoption on pedestrian traffic safety: An agent-based approach

When operated at low speeds, electric and hybrid vehicles have created pedestrian safety concerns in congested areas of various city centers, because these vehicles have relatively silent engines compared to those of internal combustion engine vehicles, resulting in safety issues for pedestrians and cyclists due to the lack of engine noise to warn them of an oncoming electric or hybrid vehicle. However, the driver behavior characteristics have also been considered in many studies, and the high end-prices of electric vehicles indicate that electric vehicle drivers tend to have a higher prosperity index and are more likely to receive a better education, making them more alert while driving and more likely to obey traffic rules. In this paper, the positive and negative factors associated with electric vehicle adoption and the subsequent effects on pedestrian traffic safety are investigated using an agent-based modeling approach, in which a traffic micro-simulation of a real intersection is simulated in 3D using AnyLogic software. First, the interacting agents and dynamic parameters are defined in the agent-based model. Next, a 3D intersection environment is created to integrate the agent-based model into a visual simulation, where the simulation records the number of near-crashes occurring in certain pedestrian crossings throughout the virtual time duration of a year. A sensitivity analysis is also carried out with 9000 subsequent simulations performed in a supercomputer to account for the variation in dynamic parameters (ambient sound level, vehicle sound level, and ambient illumination). According to the analysis, electric vehicles have a 30% higher pedestrian traffic safety risk than internal combustion engine vehicles under high ambient sound levels. At low ambient sound levels, however, electric vehicles have only a 10% higher safety risk for pedestrians. Low levels of ambient illumination also increase the number of pedestrians involved in near-crashes for both electric vehicles and combustion engine vehicles.