A model of the vicious cycle of a bus line

It has been frequently noted that in a non-regulated environment the development of public transport service is self-adjusting: Faced with decreasing demand, operators will tend to reduce service to cut costs, resulting in a decrease in the level-of-service, which then triggers a further drop in demand. The opposite may also occur: high demand will induce the operator to increase supply, e.g. through an increase in frequency, which results in a higher level-of-service and a subsequent increase in passenger numbers, triggering another round of service improvements. This paper adds to the literature by presenting an analytic model for analyzing these phenomena that we call vicious and virtuous cycles. Based on field data regarding passengers’ variation in willingness-to-wait for a public transport service, we investigate the dynamics of the line service and show how the emergence of a vicious or virtuous cycle depends on the total number of potential passengers, the share of captive riders, and bus capacity. The paper ends with a discussion of the implications of the findings for the planning of public transport services.     

城市轨道交通直流牵引监控系统的研究

阐述直流牵引供电系统是城市轨道交通供电系统中一个特殊重要的部分,直流牵引系统监控自动化是整个供电系统自动化工程实施的核心.分析直流牵引系统的功能需求,提出CAN总线与以太网相结合的直流牵引监控系统设计方案,并详细讨论系统设计的硬件组成与软件结构.     

客车结构杆连接的真实形状对结构计算的影响

本文应用有限元分析法，研究了承载式客车底加中４种基本结构的杆连接的真实形状对结构扭转变形和应力计算的影响。     

客车车身蒙皮的预应力张拉工艺

介绍了客车预应力蒙皮的张拉工艺及其在丹东汽车制造厂的应用情况。采用整张预应力张拉蒙皮，可使客车外蒙皮产生一定的内应力，使其蒙皮表面绷紧，平整光滑，流畅美观；同时可消除客车行驶过程中蒙皮产生振颤噪声和鼓动声，使乘客乘坐舒适。     

大型客车车外噪声测试分析与控制

对大型豪华客车的车外噪声进行了研究，用声强法对车外噪声的主要声源进行了鉴别。对发动机及辅助装备的工作室声学特性进行了测试分析，提出了控制车外噪声的相应策略，并作了遮蔽发动机噪声的模拟试验。     

波哥大市快速公交系统建设经验

南美洲国家哥伦比亚的首都波哥大曾以交通严重堵塞、城市环境恶化而著名,被认为是一个几乎没有希望的城市.从1998年开始,波哥大实行全新的交通改革策略.3年后,它完全改变了对大众运输系统的传统观感,成功建立了一套具有特色的快速公交系统,为全球树立了城市快速公交的"波哥大模式".     

燃料电池混合动力中巴的整车设计及其能量分配控制策略

由于燃料电池技术的日臻成熟，这种清洁、高效的新型动力源正逐渐被广泛地应用在车辆领域中．因此提出了燃料电池电动中巴车的整车设计构架及其能量分配控制策略，文章主要阐述了在现有中巴车体基础上对燃料电池发动机、蓄电池以及电力驱动系统进行的优化布置，并着重对燃料电池车辆电力驱动系统的配置、车辆控制系统、蓄电池的管理系统以及车辆的能量分配控制策略作了详细论述．     

城市主干道快速公交（BRT）系统合理站距规划布局

快速公交系统充分利用道路资源，形成大容量、快捷、舒适的公交服务体系，将是承担我国大中城市出行交通的主体，是解决当前大中城市交通问题的重要途径。论文在研究城市主干道交通流行驶特性的基础上，结合城市道路网及交通特性分析、城市主干道快速公交（BBT）系统的交通功能及主干道沿线用地特征分析，提出了城市主干道快速公交（BBT）系统规划布局的合理站距。     

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回顾了公交收费理论的发展历程和研究前沿，分析了公交收费的实践经验，研究了我国城市公交收费中存在的问题，提出了相应的改革建议，用以有效地利用现有道路资源，最大限度地提高道路设施的通行能力，提供优质高效的公交服务.     

Development of a probabilistic model to optimize disseminated real‐time bus arrival information for pre‐trip passengers

In the advent of Advanced Traveler Information Systems (ATIS), the total wait time of passengers for buses may be reduced by disseminating real‐time bus arrival times for the next or series of buses to pre‐trip passengers through various media (e.g., internet, mobile phones, and personal digital assistants). A probabilistic model is desirable and developed in this study, while realistic distributions of bus and passenger arrivals are considered. The disseminated bus arrival time is optimized by minimizing the total wait time incurred by pre‐trip passengers, and its impact to the total wait time under both late and early bus arrival conditions is studied. Relations between the optimal disseminated bus arrival time and major model parameters, such as the mean and standard deviation of arrival times for buses and pre‐trip passengers, are investigated. Analytical results are presented based on Normal and Lognormal distributions of bus arrivals and Gumbel distribution of pre‐trip passenger arrivals at a designated stop. The developed methodology can be practically applied to any arrival distributions of buses and passengers.