基于EN 1317法规的汽车-护栏系统安全性能评估

汽车与路侧安全设施碰撞的单车事故数量逐年攀升,造成了大量的人员伤亡和财产损失。本文阐述了欧盟EN1317.2法规的技术要求和试验方法,涉及护栏防护等级与试验类型的规定,护栏自身特性、车辆及乘员安全性等性能评估指标。在此基础上,以N1型普通防护试验为例,选取某型乘用车与半刚性两波梁护栏实车碰撞,对护栏自身特性、试验车辆及车内乘员安全性进行了评估。研究成果对某型乘用车与半刚性两波梁护栏相关研究及研发具有指导意义。     

混凝土护栏的基础知识

论述了混凝土护栏的设计原理，对目前公路上采用的几种型式，进行了详细的分析论证，结论是就安全性能而言，高为1070mm的F型是当前最好型式的混凝土护栏。     

高缘石护栏安全性能研究

高缘石护栏以其造价低、易施工、后期养护费用低等优点在公路中得到广泛应用。文章通过计算机模拟仿真对高缘石护栏的安全性能展开研究,在AN-SYS/LS_DYNA环境下进行车辆护栏耦合体系的参数化建模与车辆运动轨迹及损害程度的计算分析,并比较了高缘石护栏和已经得到广泛应用的新泽西护栏的优劣,得出高缘石护栏是一种各项力学性能指标均符合要求的护栏型式。     

耒宜高速公路中央分隔带单坡面混凝土护栏改造方案设计探讨

耒宜高速公路路面大修导致原中央分隔带单坡面混凝土护栏有效高度减小,防护能力不足,因而需进行护栏改造设计。本文在理论上提出了3种改造方案并进行对比,对推荐方案进行计算机仿真及实车碰撞试验验证。本项目的设计及研究结论,对同类高速公路大修项目的护栏改造能起到一定借鉴作用。     

高速公路桥梁混凝土护栏防腐技术研究

高速公路桥梁混凝土防撞护栏病害在我国北方地区及高原地区较为严重,不仅影响护栏美观,更影响了混凝土护栏的防撞能力,增加了安全隐患。文章从混凝土防撞护栏施工、运营管养、病害防治措施等方面,研究混凝土护栏防腐技术措施,以减少护栏病害。     

钢筋混凝土防撞护栏的施工及裂缝治理

就钢筋混凝土防撞护栏裂缝情况进行了分析,并提出了避免措施、施工方法和应注意的常见问题.     

高速公路钢护栏改造碰撞实验研究

近几年国内很多高速公路在改造维护过程中对路面都进行了重新罩面，导致护栏板距地面高度降低，无法满足国家标准的要求。为方便旧护栏的再利用，提高经济性，采用计算机仿真技术进行方案初选后，由实车碰撞试验确定满足相关规范要求的护栏改造方案是评价护栏改造方案最直接、最有效的方法。通过此方法确定了一种施工简便且造价较低的护栏改造方案，该方案不仅简便，而且降低了护栏改造费用，减少了对运营的影响，适合应用于目前状况下我国高速公路护栏改造及再利用。     

山区公路路侧护栏等级选择方法

路侧护栏是高速公路、山区公路和桥梁路段最常用的安全保障措施。文章针对路侧安全防撞护栏等级设计中常出现的问题,提出护栏设置的六个参考准则,进而研究层次分析法(The analytic hierarchy process,AHP)在路侧护栏安全等级选择中的应用。     

我省高速公路交通工程设计方案有关问题的探讨

本文主要针对青海省高速公路交通工程在运营养护中存在的弊端,通过对中央分隔带设置防眩网或者绿化植树,以及高填方路基边坡外侧护栏设置加强型波形梁或者混凝土防撞墙两个方面的优缺点进行对比,阐明防眩网利于养护和运营安全,优点多于绿化植树;高边坡填土路基外侧护栏设置加强型波形梁,利于冬季降雪消融,行车安全,优点多于钢筋混凝土防撞墙。     

公路护栏碰撞分析及探讨

随着我国公路里程数和车辆保有量日益增长,道路交通事故中的公路护栏碰撞问题也层出不穷,迫切需要对交通安全设施工程进行专项研究。文章通过分析公路护栏问题存在的现状,研究国内外护栏规范水平差异、设计原则及影响因素,分析了护栏碰撞问题囊括的运动学、动量定理、质量及能量守恒法公式,并对车辆碰撞公路护栏的数值模拟进行研究,得出评价及建议,研究成果可为交安工程设计和施工提供参考。     

桥梁护栏涂层防腐处治实践

文章针对宣大高速公路沿线桥梁护栏的侵蚀性损伤,提出了涂层防腐处治方法,介绍了涂层防腐材料及其作用,并阐述了涂层防腐处治施工的工艺流程和技术要点。     

Green vehicle technology to enhance the performance of a European port: A simulation model with a cost-benefit approach

In this paper, we study the impact of using a new intelligent vehicle technology on the performance and total cost of a European port, in comparison with existing vehicle systems like trucks. Intelligent autonomous vehicles (IAVs) are a new type of automated guided vehicles (AGVs) with better maneuverability and a special ability to pick up/drop off containers by themselves. To identify the most economical fleet size for each type of vehicle to satisfy the port’s performance target, and also to compare their impact on the performance/cost of container terminals, we developed a discrete-event simulation model to simulate all port activities in micro-level (low-level) details. We also developed a cost model to investigate the present values of using two types of vehicle, given the identified fleet size. Results of using the different types of vehicles are then compared based on the given performance measures such as the quay crane net moves per hour and average total discharging/loading time at berth. Besides successfully identifying the optimal fleet size for each type of vehicle, simulation results reveal two findings: first, even when not utilising their ability to pick up/drop off containers, the IAVs still have similar efficacy to regular trucks thanks to their better maneuverability. Second, enabling IAVs’ ability to pick up/drop off containers significantly improves the port performance. Given the best configuration and fleet size as identified by the simulation, we use the developed cost model to estimate the total cost needed for each type of vehicle to meet the performance target. Finally, we study the performance of the case study port with advanced real-time vehicle dispatching/scheduling and container placement strategies. This study reveals that the case study port can greatly benefit from upgrading its current vehicle dispatching/scheduling strategy to a more advanced one.     

Simulator evaluation of incident detection by transponder-equipped vehicles

This paper explores the efficacy of the driver-based incident detection using the vehicle-to-roadside communication (VRC) system. The proliferation of vehicle tags in the US for automatic toll collection, traffic monitoring, and vehicle navigation and information systems has created an infrastructure capable of supporting a driver-based incident detection system. The research reported herein investigated the use of "activatable" vehicle tags by drivers to send an incident signal to the Traffic Management Center through VRC reader stations spaced uniformly on a highway. The simulation results showed that good detection performance was achieved even at lower levels of market penetration of vehicle tags. The results further showed that detection performance is significantly affected by the severity of the incident in terms of number of lanes closed, the spacing of the VRC reader stations, traffic volume at the time of the incident, and the reporting propensity of the traveling public.The performance of the VRC-based incident reporting system was compared to the performance of two incident detection algorithms that rely on traffic data collected through the automatic vehicle identification (AVI) system. The comparison showed that the VRC-based incident reporting system attained shorter detection times and higher detection rates under fairly similar simulated conditions. The paper also discusses issues that need further study through simulation and field experimentation of the VRC-based incident reporting system.     

Investigating the applicability of exclusive pedestrian phase at two‐phase actuated controlled intersections

The exclusive pedestrian phase (EPP) has been used in many countries to promote walking around downtown areas by increasing the ease and convenience of pedestrian crossing. However, its applicability has not been systematically demonstrated, especially when an intersection is operated in actuated mode. This paper presents an extensive simulation‐based analysis of the applicability of EPP as compared with a normal concurrent pedestrian‐phase pattern at an isolated intersection controlled by actuated logic. Actuated signal control logics for EPP‐actuated and conventional concurrent pedestrian phase‐actuated controls are developed. Both of these control logics consider pedestrian crossing demands and can adapt to changes in vehicle traffic to reduce vehicle delay as well. A simulation model of a two‐phase controlled intersection is built and calibrated based on field data using VISSIM (PTV Planung Transport Verkehr AG in Karlsruhe, Germany). Extensive analysis is conducted to reveal fully the applicable EPP domain in terms of vehicle traffic demand, pedestrian demand, vehicle turning ratio, and pedestrian diagonal crossing ratio. The results show that the performance and applicable domain of EPP are jointly determined by those five factors. EPP significantly outperforms concurrent pedestrian phase if the vehicle turning ratio is greater than 0.6 and the pedestrian diagonal crossing ratio is greater than 0.6. These results can help traffic engineers in choosing the appropriate pedestrian‐phase patterns at actuated signalized intersections. Copyright © 2015 John Wiley & Sons, Ltd.     

防风网工程防撞措施研究

防风网工程是一种应用于港口露天煤堆场的环保构筑物,然而煤堆场内转运煤炭的货车数量多且出入频繁,给道路周边的防风网带来了安全隐患。文章分析了港区货车撞击防风网等构筑物事故发生的原因,介绍了防撞措施的设置原则,提出了刚性防撞、柔性防撞、绿化带防撞、夜间防撞等被动防撞措施。     

CO2 emissions correction of light-duty vehicles based on an energy deviation analysis method

In present study, a total of 3 types of light-duty vehicles were tested for 7 types of driving modes by using a vehicle dynamics-based simulation method. Deviations between the target and actual test vehicle speed and inaccurate chassis dynamometer road load settings are selected as the two main factors affecting the CO₂ emission measurement test. 126 cases of simulations were conducted to analyze the effects of the deviation between the target and actual test vehicle speed on CO₂ emissions and 63 cases of simulation were conducted to analyze the effectiveness of inaccurate road load test conditions on CO₂ emissions. Then, the CO₂ correlation method proposed by World Forum for Harmonization of Vehicle Regulations (WP.29, UN) was applied for simulated results in original simulation cases, and a correction to performance was validated by comparative analysis. From the simulation results, it is revealed that velocity and road load deviation are related to distinct changes in fuel efficiency and CO₂ emission rates of test vehicles. Also, it is revealed that CO₂ correction method show good performance to reduce the relative error lower than 2% in all test cases.     

Vehicle actuated signal performance under general traffic at an isolated intersection

We study green extension of a two-phased vehicle actuated signal at an isolated intersection between two one-way streets. The green phase is extended by a preset time interval, referred to as critical gap, from the time of a vehicle actuation at an advance detector. The green phase switches if there is no arrival during the critical gap. We develop an exact model to study the intersection performance with traffic following Poisson processes. We further extend the model to approximate the case of general traffic. Our model in the general case works well compared with Monte Carlo simulation. A few major observations include: (1) The optimal critical gap decreases with the traffic; (2) The optimal critical gap can be much larger (up to 5 s) than the common presumption of 2–3 s; (3) Queue clearance policy is not nearly optimal in general even in the case of heavy traffic.     

Development of a simulation platform for safety impact analysis considering vehicle dynamics,sensor errors,and communication latencies: Assessing cooperative adaptive cruise control under cyber attack

While safety is one of the most critical contributions of Cooperative Adaptive Cruise Control (CACC), it is impractical to assess such impacts in a real world. Even with simulation, many factors including vehicle dynamics, sensor errors, automated vehicle control algorithms and crash severity need to be properly modeled. In this paper, a simulation platform is proposed which explicitly features: (i) vehicle dynamics; (ii) sensor errors and communication delays; (iii) compatibility with CACC controllers; (iv) state-of-the-art predecessor leader following (PLF) based cooperative adaptive cruise control (CACC) controller; and (v) ability to quantify crash severity and CACC stability. The proposed simulation platform evaluated the CACC performance under normal and cybersecurity attack scenarios using speed variation, headway ratio, and injury probability. The first two measures of effectiveness (MOEs) represent the stability of CACC platoon while the injury probability quantifies the severity of a crash. The proposed platform can evaluate the safety performance of CACC controllers of interest under various paroxysmal or extreme events. It is particularly useful when traditional empirical driver models are not applicable. Such situations include, but are not limited to, cyber-attacks, sensor failures, and heterogeneous traffic conditions. The proposed platform is validated against data collected from real field tests and tested under various cyber-attack scenarios.     

Evaluating the effects of bus design on passenger flow: Is agent-based simulation a feasible approach?

In this paper, we propose an agent-based simulation approach that is capable of simulating the flow of passengers on board buses and at bus stops. The intention is that it will be applied during vehicle development to analyze how vehicle design affects passenger flow, and thus also how it affects system performance such as dwell time. In turn, this could aid the developers in making design decisions early in the development process. Besides introducing the simulation tool itself, the paper explores the realism of the data generated by the tool. A number of passenger flow experiments featuring a full-scale bus mockup and 50 participants were carried out. The setup of these experiments mirrored a number of ‘bus journeys’ (regarding vehicle design, number of passengers boarding/alighting at each stop and so on) that had previously been simulated using the simulation tool. When the data from the simulations were compared with the data from the passenger flow experiments, it could be concluded that the tool is indeed able to generate realistic passenger flows, although with some errors when a large number of passengers board/alight. The simulated dwell times were rationally affected by the tested bus layout aspects. It was concluded that the tool makes it possible to evaluate how variations in bus layouts affect passenger flow, providing data of sufficiently high quality to be useful in early phases of vehicle design.