通渭路黄河大桥交通影响评价

文章基于现阶段兰州市道路、桥梁交通量情况,对拟建的通渭路黄河大桥设计方案进行了交通影响评价,并探讨了项目建成后可能存在的问题及相应的解决措施。     

我国北极通航瓶颈问题分析

随着全球气温变暖趋势的显现,北极通航问题日益受到各方面的关注但是要实施北极通航,必须对可能面,临的困难和问题有清楚的认识文中从法律法规、环境保护、船舶和航行奈件,以及船员培训和认证等方面,对中国实施北极通航可能存在的一些瓶颈问题作了初步分析,可为从事北极通航问题研究人员提供参考     

大城市交通拥堵致因的故障树分析

为解决拥堵问题,提出将故障树分析法引入道路交通拥堵中。对道路拥堵故障树进行了相关说明,以北京丰台区广安路为例,构建道路拥堵的故障树模型,分析引起拥堵的所有可能原因,并通过定性和定量分析找出了主要拥堵原因,给出了解决道路拥堵的方案。     

单坡型桥梁混凝土护栏裂纹防撞性能影响分析

由于混凝土材料抗拉强度低的特点,单坡型桥梁钢筋混凝土护栏通常是带裂纹工作的。为了研究裂纹对于单坡型桥梁钢筋混凝土护栏防撞性能的影响,总结了单坡型桥梁钢筋混凝土护栏裂纹特点,并进一步分析了单坡型桥梁钢筋混凝土护栏裂纹的类型。在此基础上,本文采用文献资料调研、理论分析以及计算机仿真方法分析了单坡型桥梁钢筋混凝土护栏裂纹对其防护能力的影响,认为虽然混凝土材料在裂纹处不连续,但由于钢筋的存在,不会影响护栏作为纵向的连续结构整体发挥安全防护作用,因此裂纹对单坡型桥梁钢筋混凝土护栏的防护能力没有影响。本文最终通过实车碰撞试验对分析结果进行了验证。     

Is road pricing effective in abating pollution? Evidence from Milan

We estimate the effect of a road pricing policy introduced in Milan in 2008 on concentrations of benzene, carbon monoxide, particulates, nitrogen dioxide and sulphur dioxide. We found a sizeable effect of the Ecopass on air quality in terms of reduction in the concentration of carbon monoxide and particulates a few days after its introduction, although this effect disappeared after only one week. We interpret these results as indicative of an inefficient policy design: motorbikes were not charged and the treated area is too limited to generate positive outcomes for the whole city. Further evidence from a natural experiment given by a temporary suspension of the charge in 2012 confirms our hypothesis on the incentives for motorbike usage.     

论述智能网联汽车的发展

智能网联汽车越来越受人们的关注,文章介绍了智能网联汽车的背景以及国内外研究现状和对智能汽车的智能化等级划分标准,以及智能汽车的技术体系架构的组成,介绍了环境感知系统,智能汽车的检测方法及智能汽车在交通安全方面的应用,简介闯红灯提醒、盲区来车提醒、避撞提醒和紧急制动提醒等。最后就目前的发展状况,提出智能汽车发展过程中存在的安全问题。     

Controlling road congestion via a low-complexity route reservation approach

This work introduces a novel route reservation architecture to manage road traffic within an urban area. The developed routing architecture decomposes the road infrastructure into slots in the spatial and temporal domains and for every vehicle, it makes the appropriate route reservations to avoid traffic congestion while minimizing the traveling time. Under this architecture, any road segment is admissible to be traversed only during time-slots when the accumulated reservations do not exceed its critical density. A road-side unit keeps track of all reservations which are subsequently used to solve the routing problem for each vehicle. Through this routing mechanism, vehicles can either be delayed at their origin or are routed through longer but non-congested routes such that their traveling time is minimized. In this work, the proposed architecture is presented and the resulting route reservation problem is mathematically formulated. Through a complexity analysis of the routing problem, it is shown that for certain cases, the problem reduces to an NP-complete problem. A heuristic solution to the problem is also proposed and is used to conduct realistic simulations across a particular region of the San Francisco area, demonstrating the promising gains of the proposed solution to alleviate traffic congestion.     

格尔木铁路综合客运枢纽交通规划及综合开发研究

为了实现格尔木铁路综合客运枢纽交通功能最优化与开发收益最大化,对枢纽交通规划及综合开发进行研究意义重大。枢纽交通规划从客流预测、交通换乘、设施规模预测、设施布局、车场布置、客流组织、外部道路交通优化分析,枢纽综合开发从业态需求、业态定位、地块价值、业态布局、收益测算研究。研究表明,格尔木铁路综合客运枢纽在可实现交通功能最优的同时,确保综合开发盈利弥补建设运营的亏损,为类似项目提供借鉴参考。     

简析广州大学城交通

区域的发展，离不开交通的支撑，交通问题成了影响大学城可持续发展的重要因素之一。本文简述广州大学城交通具有道路网密集、停车场存在供求矛盾等特点，并概括大学城师生表现出学生以公共交通出行为主、师生出行耗时长、换乘不便等出行特征，由此揭示大学城存在公交班次设计不尽合理、超载现象时有发生等问题，最后提出根据客流情况而适当增加班次、设置进入校园的路标指示牌、实行必要交通管制等建议与对策。     

A multi-class model-based control scheme for reducing congestion and emissions in freeway networks by combining ramp metering and route guidance

The paper proposes a multi-class control scheme for freeway traffic networks. This control scheme combines two control strategies, i.e. ramp metering and route guidance, in order to reduce the total time spent and the total emissions in a balanced way. In particular, the ramp metering and route guidance controllers are feedback predictive controllers, i.e. they compute the control actions not only on the basis of the measured system state, but also on the basis of the prediction of the system evolution, in terms of traffic conditions and traffic emissions. Another important feature of the controllers is that they have a multi-class nature: different classes of vehicles are considered and specific control actions are computed for each class. Since the controllers are based on a set of parameters that need to be tuned, the overall control framework also includes a module to properly determine the gains of the controllers. The simulation analysis reported in the paper shows the effectiveness of the proposed control framework and, in particular, the possibility of implementing control policies that are specific for each vehicle type.