Point-to-point speed enforcement systems: Speed limits design criteria and analysis of drivers’ compliance

Point-to-point (P2P) speed enforcement is a relatively new approach to traffic law enforcement. Its technology allows vehicles whose average speed exceeds the speed limit over the controlled section to be fined. It therefore encourages compliance over distances longer than those where spot enforcement policies have been in place.In this paper, a procedure for consistently setting speed limits with such enforcement systems is proposed. Such a method has been applied to design the speed limits on two motorways in the district of Naples, Italy, where P2P enforcement systems became operational in 2009 and 2010. The speed limits, which were set using the Italian geometric design standard to assess vehicle stability and stopping sight distance, have been compared with those provided by using well-known international standards.The impact of the newly designed speed limits and of the P2P enforcement system on drivers’ speeding behaviour has been quantified for each highway section and vehicle type. In fact, accurate measurements of the average travel speeds of each vehicle crossing the enforced sections, before and after the activation of the system, were available. The migration from the old speed limits with spot speed enforcement to the new approach resulted in a notable increase in drivers’ compliance to the speed limits with a remarkable decrease in both the average of individual speeds and in their standard deviation.In addition, the analysis of 3 years of data shows that a gradual adaptation of drivers’ behaviour to the system took place. In particular, a decreasing compliance to the speed limits points to a non-optimal system management. Finally, the results of a revealed preference survey allowed us to make a behavioural interpretation regarding the significantly different impacts measured on the two motorways.     

Estimation of delay variability at signalized intersections for urban arterial performance evaluation

Urban arterial performance evaluation has been broadly studied, with the major focus on average travel time estimation. However, in view of the stochastic nature of interrupted flow, the ability to capture the characteristics of travel time variability has become a critical step in determining arterial level of service (LOS). This article first presents a stochastic approach that integrates classic cumulative curves and probability theories in order to investigate delay variability at signalized intersections, as a dominant part of the link travel time variability. This serves as a basis for arterial travel time estimation, which can be obtained through a convolution of individual link travel time distributions. The proposed approach is then applied in the estimation of travel time along one arterial in Shanghai, China, with abundant automatic vehicle identification (AVI) data sources. The travel time variability is evaluated thoroughly at 30-min intervals, with promising results achieved in comparison to the field measurements. In addition, the estimated travel time distributions are utilized to illustrate the probability of multiple LOS ranges, namely, reliability LOS. The results provide insights into how we might achieve a more reliable and informative understanding of arterial performance.     

基于SHEL和三角模糊数理论的地铁钻爆法施工安全评价方法研究

为合理应用决策数据中不同专家的背景知识,找出地铁施工过程中安全测评体系的关注重点,根据地铁施工的特点和SHEL安全模型理论,建立以人-软件(L-S)、人-硬件(L-H)、人-环境(L-E)和人-人(L-L)4个环节为基础的钻爆法地铁施工安全指标体系。请专家给出指标语义评价等级和指标权重语义评价等级,并根据其与三角模糊数的对应关系分别得出三角模糊数评价值。针对不同专家的重要性程度差异,提出基于三角模糊数的群一致性评价方法,得出专家综合权重,集结评价数据,最终得到安全评价结果。最后,对青岛地铁1号线过海段进行实例分析。结果表明,该方法可以解决群评价过程中专家个体权威与群体共识难以兼顾的问题,能够充分利用群决策中的原始评价信息,提高地铁施工安全水平评价的准确性。     

城市灯控平面交叉口的自行车交通设计研究

城市灯控平面交叉口混合交通流安全和效率的核心研究对象应该是自行车与机动车交通流间的相互影响。本丈在大量的理论分析和实践的基础上,探讨时空分离法的自行车交通设计的基本原则和交通空间设计方法,即自行车右转弯专用车道设计、左转自行车二次过街以及自行车与行人过街一体化设计,并进行了南京市太平北路与珠江路交叉口的应用实例分析。本文的城市灯控平面交叉口自行车的交通设计方法可为解决城市灯控平面交叉口混合交通问题提供借鉴。     

构建网络安全体系,保障电子政务畅通

构建安全的电子政务网络体系对于推动政府工作信息化、促进政务公开、提高政府办公效率、构建和谐社会是非常重要的.在详细介绍目前网络安全一些认识误区的基础上,结合实际工作经验,从技术实施、制度建设方面阐述了如何构建安全的网络体系的问题.     

平交路口远引掉头设置方法分析

平交路口远引是解决路口流向禁限后车流转向问题的有效方法。通过对掉头地点的选址规划以及交叉口之间的协调控制进行研究,提出最佳掉头位置应满足的条件以及交叉口协调控制的相位差计算方法。通过对掉头通道通行能力的分析,提出实施掉头信号控制条件和具体实施方法。     

一级公路交叉口设计中的交通安全问题及对策

一级干线公路由于开口较多,不可避免地存在较多的交通安全问题.文章以湖北荆监一级公路为例,针对交叉口设计中的交通安全典型问题,提出了改善方法及相关对策.     

福州市交通安全与智能交通系统探讨

智能交通系统是一个高科技集成系统,它综合运用各种高新技术于整个交通管理系统之中,可以系统、全面、高效地提高交通运输的安全性.文章阐述了智能交通系统在交通安全中的作用及在福州市的应用情况,指出了福州市发展智能交通的方向,以提高福州市的交通安全管理水平.     

基于FDS公路隧道火灾仿真研究

针对公路隧道突发火灾事故问题,采用模拟软件对隧道发生的火灾进行研究。分析火灾条件下公路隧道内被困人群的疏散行为特点,给出隧道内人员疏散的安全依据,按照隧道火灾条件下通风风速不同时火灾烟气蔓延情况,确定火灾可利用疏散时间(ASET),通过分析人员疏散特点计算出所需的疏散时间(RSET),通过对比得出:通风风速至少为3m/s时才能保证人员的安全疏散。     

厦门地铁2号线钻探工程海上通航安全评估

依据港口通航现状、港口发展规划、附近海域船舶交通现况,分析通航安全形势,预测厦门轨道交通2号线跨海路段施工期间,船舶交通流可能的变化和通航环境、通航秩序的适应能力,论证在施工期间存在的通航安全风险、主要问题及通航安全保障能力,并提出保障通航安全的可行性建议和措施.