交通拥堵智能监测的车联网环境构建

车联网是互联网以及物联网通讯技术引入交通领域而发展出来的一类智能交通应用技术。本文在解析车联网基本架构体系的前提下,围绕交通拥堵智能监测的优化实现,基于V2V模型,构建一种智能监测的车联网典型应用环境,并参考车联网基本特征,探讨定义智能监测条件下的交通拥堵评价基准。     

Network-wide traffic and environmental impacts of acceleration and deceleration among Eco-Driving Vehicles in different road configurations

Eco-Driving, a driver behaviour-based method, has featured in a number of national policy documents as part of CO₂ emission reduction or climate change strategies. This investigation comprises a detailed assessment of acceleration and deceleration in Eco-Driving Vehicles at different penetration levels in the vehicle fleet, under varying traffic composition and volume. The impacts of Eco-Driving on network-wide traffic and environmental performance at a number of speed-restricted road networks (30?km/h) is quantified using microsimulation. The results show that increasing levels of Eco-Driving in certain road networks result in significant environmental and traffic congestion detriments at the road network level in the presence of heavy traffic. Increases in CO₂ emissions of up to 18% were found. However, with the addition of vehicle-to-vehicle or vehicle-to-infrastructure communication technology which facilitates dynamic driving control on speed and acceleration/deceleration in vehicles, improvements in CO₂ emissions and traffic congestion are possible using Eco-Driving.     

A commuting model for the analysis of the impacts of a tramway project: application to the Lens area

Road congestion is not only an issue for major European urban agglomerations, but also for smaller ones. It is also the case of the Lens urban area, where car use is much higher than the average for medium-sized urban agglomerations in France. Local authorities put forward tramway projects to deal with the strongly negative externalities of congestion: travel time losses and pollution. To analyse its medium-term impact, we have developed a commuting with congestion model, inspired by the four-step traditional model, but with data made available from an origin–destination matrix. The results are encouraging but insufficient, and it is necessary to adopt supplementary measures in order to retrieve and justify the sizeable investments needed. Some measures prove to be very efficient, such as parking fees and urban tolls. Other measures, such as the subsidization of public transport, are partially efficient since they have an impact mainly on intra-urban commutes.     

城市道路交通拥堵评价和判定标准研究

随着汽车保有量的增加,城市交通需求量也持续膨胀,使得交通拥堵成为城市发展亟须解决的问题。鉴于此,首先,以车道占有率和速度跃迁概率为基本指标,提出一种新的交通流状态划分方法。随后,研究了交通流参数时变特性及不同车道间的交通流特性,提出了交通拥堵状态的判定算法和指标。最后,分析了城市道路交通拥堵评价层次和评价体系(指标),并得到了评价特定区域内交通拥堵严重程度的城市交通行程时间指数模型。     

城市宏观交通组织思路及方法

阐述了城市宏观交通组织对解决城市交通问题的意义,在此基础上,从道路可接受服务水平、交通组织措施优选和拥堵范围3个角度分析了城市宏观交通组织方案的设计思路,给出了较完整的交通组织方案设计流程,并将其模拟应用于重庆朝天门地区交通组织方案优化。     

基于VISSIM的城市施工路段堵塞对策研究

以武汉市街道口施工路段为例,利用实地调查交通数据,得出拥堵车辆中小汽车为大多数,并采用交通仿真软件VISSIM模拟不同交通状况下交通流运行情况,在保证施工顺利进行和正常交通秩序的前提下,分析并提出了建造临时桥梁以解决施工路段堵塞的方法。     

居民出行时间选择及拥挤收费政策

应用基于活动的出行需求预测方法,分析了居民出行的时间分布规律与影响居民出行时间选择的因素,分别建立了出发和到达时间选择模型,用长春市居民出行调查数据对模型进行了标定和验证。用已建模型对比评价了两种拥挤收费政策,证明了调整高峰时段小汽车出行费用策略不仅可以使居民的高峰时段出行减少大约18％,而且可以抑制小汽车出行,调整城市交通方式分配结构,说明已建模型可以全面有效地进行交通需求管理政策的评价。     

兰州市“畅交通”工程旧城道路抢修设计与施工

该文介绍了兰州市天水中路道路路面拓宽、非机动车道及人行道提升改造、缓解交通拥堵、各类检查井覆盖及提升、更换收水井等旧城道路改造工程中的一些经验和做法,可供同行参考。     

城市快速路交通拥挤形成时机判定及其控制策略研究

通过对城市快速路交通拥挤特性的分析,提出了交通拥挤形成时机判定的思想,力争在拥挤产生之前就对交通流加以控制,避免交通拥挤的产生;并从全局最优的角度,提出了以路段服务流量最大为目标的可变限速和入口匝道联合控制策略,建立了相应的模型及算法;最后对该方法进行了仿真试验,并与原始方法进行对比.结果表明,这一方法将城市快速路的服务流量提高11.3%,可避免拥挤的产生,维持车流的稳定.     

双振捣轴加工工装的改进方案

用车床和外圆磨床组合的方式经济而高效地生产摊铺机双振捣轴,加工工装起着十分重要的作用。介绍了现有的2种不同工装的工艺及特点,通过分析,推荐了一种优先采用的方案。