Vehicle Positioning for Improving Road Safety

Abstract

Vehicle positioning is a key requirement for many safety applications. Active safety systems require precise vehicle positioning in order to assess the safety threats accurately, especially for those systems which are developed for warning/intervention in safety critical situations. When warning drivers of a local hazard (e.g. an accident site), accurate vehicle location information is important for warning the right driver groups at the right time. Global positioning system and digital maps have become major tools for vehicle positioning providing not only vehicle location information but also geometry preview of the road being used. Advances in wireless communication have made it possible for a vehicle to share its location information with other vehicles and traffic operation centres which greatly increases the opportunities to apply vehicle positioning technologies for improving road safety. This paper presents a state‐of‐the‐art review of vehicle positioning requirements for safety applications and vehicle positioning technologies. The paper also examines key issues relating to current and potential future applications of vehicle positioning technologies for improving road safety.     

21世纪的轮胎维护

有一些汽修厂的老板或技师可能一直认为轮胎的日常维护没什么技术含量。但是轮胎中一些新技术的出现可能要更新这种的观念。[第一段]     

意大利安全投资中获利

意大利拥有欧洲最安全的官方铁路。来自国际铁路联盟的数字表明，意大利连续五年平均每百万列车公里的事故数．与其对手公司——西班牙Renfe公司最接近．并且其事故数大大低于奥地利联邦铁路和比利时国家铁路的事故数。     

Deployment of interurban ATT test scenarios (DIATS): Implications for the European road network

The paper summarizes the research results and implications from the DGVII-funded Fourth Framework research project Deployment of Interurban ATT Test Scenarios (DIATS). The objective of DIATS was to identify options available in the short and medium terms, for implementing advanced transport telematics (ATT) systems for motorway-type roads and to develop scenarios of 'highest potential impact' for each of the systems identified. Included are the results of a Delphi study into the most likely deployment scenarios for ATT technologies. The methodology developed to assess the organizational, social, environmental, efficiency, safety and legal concerns associated with new ATT systems is then described. This includes stated preference questionnaires, traffic simulation modelling, driver behaviour assessment using an instrumented vehicle, analysis of accident databases and literature reviews. A multicriteria analysis of the impacts of a range of ATT systems is then presented. In particular, the results discuss the potential impacts of new in-vehicle driver assistance devices such as adaptive cruise control on the operation and effectiveness of existing fixed-infrastructure systems. The paper concludes with a prioritized list of deployment strategies of maximum impact for all of the systems assessed. The research findings are already being applied nationally and a number of field trial assessments that will assist in this are also proposed.     

汽车新技术开发及推广(上)

在未来几年之内,汽车行业将会执行更加严格的燃油经济性法规。为此,汽车设计和结构制造技术都发生了显著的变化来适应未来新法规对燃油经济性的要求。各汽车厂商2011年的新车型已悉数在美国市场亮相,而其中一些改进后将被称为2012款新车型的产品也将按计划在未来的几个月内陆续在美国汽车市场发     

Fuzzy Logic Traction Controllers and their Effect on Longitudinal Vehicle Platoon Systems

This paper presents two fuzzy logic traction controllers and investigates their effect on longitudinal platoon systems. A fuzzy logic approach is appealing for traction control because of the nonlinearity and time-varying uncertainty involved in traction control systems

The fuzzy logic traction controllers we present regulate brake torque to control wheel slip, which is the normalized difference between wheel and vehicle speed. One fuzzy controller estimates the peak slip corresponding to the maximum tire-road adhesion coefficient and regulates wheel slip at the peak slip. The controller is attractive because of its ability to maximize acceleration and deceleration regardless of road condition. However, we find through simulations the controller's performance degrades in the presence of time-varying uncertainties. The other fuzzy logic controller regulates wheel slip at any desired value. Through simulations we find the controller robust against changing road conditions and uncertainties. The target slip is predetermined and not necessarily the peak slip for all road conditions. If the target slip is set low, stable acceleration and deceleration is guaranteed, regardless of road condition

We also study the effect of traction control on longitudinal vehicle platoon systems using simulations. The simulations include acceleration and deceleration maneuvers on an icy road. The results indicate traction control may substantially improve longitudinal platoon performance, especially when icy road conditions exist.     

The significance and measurement of variability in travel behaviour

It is argued that an understanding of variability is central to the modelling of travel behaviour and the assessment of policy impacts, and is not the peripheral issue that it has often been considered. Drawing on recent studies in the UK and Australia, in conjunction with a review of the literature, the paper first examines the policy and analytical rationale for using multi-day data, then illustrates different ways of measuring variability, and finally discusses issues relating to the collection of suitable data for such analyses. In a policy context, there is a growing need for multi-day data to examine issues that affect general rather than one-day behaviour (e.g. to assess the distribution of user charges for road pricing, or patterns of public transport usage); while analytically, multi-day data is needed to improve our ability to identify the mechanisms behind travel behaviour and to derive better empirical relationships. Three measures of variability are presented: a graphical form showing daily differences in behaviour at the individual level; an aggregate, similarity index; and a hybrid graphical/numerical measure, which provides new insights into variability in daily patterns of behaviour. The paper raises a number of issues for debate, probably the most crucial of which is: variability in what? The way in which behaviour is measured crucially affects our conception of stability and variability.     

列车维护保养的前沿技术

在诺撒姆(Nonham)列车维护中心，由计算机控制的高尖端设备已成为车辆维护的核心组成部分。除了列车维护车间所采用的普通设备外，诺撒姆中心的设施还包括3台铁路专用设备，即车轮旋床、转向架拆卸设备和车辆清洗机，它们在各自的领域均属于前沿技术。     

蓄电池主动负荷管理系统

汽车设计人员一直在不懈地努力,试图通过技术手段来提高车辆的燃油经济性。为此,也对蓄电池提出了更高的要求。新技术的发展将会从很多方面大大改进蓄电池的功能,使其具有更长的使用寿命。     

抑制点火系统产生的电磁干扰

有些人采取的屏蔽手段真令我啼笑皆非。最近我就见到一个车主,他的福特车采用的是插入式点火系统（点火线圈插在火花塞上,即COP）。这位车主把发动机上8个点火线圈都用铜色铝箔包上。我问他为什么这样做,他回答说是为了消除点火系统对无线电频率的干扰,使收音机能正常收听。