基于数据流集成回归的短时交通流预测

传统的交通流预测技术使用静态和离线算法,无法对模型的参数值和内部结构进行在线调整.然而,交通流变化具有明显的动态性,其内在模式会随时间发生变化,导致构建好的模型准确度下降.针对上述问题,提出了基于数据流集成回归的短时交通流预测模型.将不断产生的交通流数据划分成数据块,每个数据块训练1个基础回归模型,然后加权组合为集成模型.通过不断训练新的基础模型,并置换出集成模型中准确度最差的基础模型,实现在线更新.在实测数据上的对比实验结果表明,与静态离线的BN模型相比,模型的均方根误差降低了19.5%,运算时间降低了48.7%,并能够快速适应交通状况发生明显变化的情况,适用于城市主干道路的短时交通流预测问题.      

Traffic flow consideration in design of freight distribution system

This study is part of a series of research projects on a distribution system we developed to deal with cases in a state-owned company. It concerns the design of the Public Service Obligation State-owned Company (PSO-SOC) distribution system. The intrinsic features of PSO-SOC are distributing strategic commodities and having subsidies within the cost function. Hence their distribution flow has to be secured under consideration of moving the commodities within road networks that have traffic flow dependency. This paper focuses on the solution of the proposed model which represents traffic flow dependency within a freight distribution network.The mathematical formulation takes the form of a Minimum Cost Multicommodity Flow (MCMF) problem. Traffic flow dependency is incorporated into the model by introducing a coefficient of speed, which is derived from the traffic assignment of ordinary traffic associated with the transportation of the type of freight under consideration The solution of the proposed model is formulated by Network Representation (NR), in which all of the components of the mathematical model are represented in the form of dummy links and nodes added to the original (physical) network. It is to be noted then, that the traffic flow on each road or link is represented by a link performance function (LPF), depicting traffic flow dependent travel time and consequent cost. The MCMF problem of NR is further solved by a Primal-Dual Algorithm.Finally, an illustrative example is exercised to show how the proposed step-wise solution works.     

自动化公路货物运输量统计方法

为了提高中国公路货运统计的真实性和统计效率，利用自动化交调、轴载检测、高速公路计费、联网联控货车以及国家道路货运量专项调查等数据，提出2种自动化公路货运量统计方法。2种方法均采用浮动检测数据与固定检测数据融合的原理，使用浮动车数据获得运输特征，分别使用高速计费数据及自动化交调数据获得运输规模。通过设备检测数据与人工调查数据的嵌套计算，解决分层统计中行业浮动车代表性不足的问题。通过数据的一致性分析，解决不同类型数据车型划分标准不同给数据融合带来的口径不一致问题。与传统方法相比，统计方式由人工统计转变为自动化统计；统计对象由营运性货车扩展为全社会货车；统计口径由按车籍地统计转变为按运输发生地统计；统计周期由月缩短为日。此外，实现了可按车辆类型、道路类型、运输成分及公路线路的精细化统计。以辽宁省路网和G102国道为例，给出区域公路网和公路线路的货运量统计结果。最后，以高速公路为统计对象，与计费数据获得的货运量对比，验证基于交调数据统计方法的准确性。结果显示，交调融合法的货运量统计误差为11.5%。对比2种方法，交调融合法具有更广泛的适用性和更高的灵活性，为中国公路运输统计现代化发展提供了技术方法，同时探索了利用设备检测数据和人工调查数据嵌套分析解决工程问题的方法。     

基于计划延误成本的出发时间选择模型

出行时间不确定性对出行者造成诸多负面影响,其中之一就是计划延误成本增加.向出行者提供交通信息可减少出行时间不确定性的负面影响,减少计划延误成本.为了估计其负面效应和出行时间信息的价值,研究了一个出行时间不确定性下的出发时间选择模型.假定在不同的出发时间下,出行时间分布的形式不同.模型中出行者可得到交通信息服务系统(A T IS)提供的基于平均出行状况的交通信息或基于当日出行状况的交通信息,同时他对得到的信息有自己的感知值,基于此感知预测出行时间并选择出发时间.用算例反映了出行时间不确定性、不同信息状况和信息预测的质量对出行者广义出行阻抗的影响.结果表明交通信息的收益不应该只表现为传统的出行时间节省,它还能减少约30% ~40% 的计划延误成本.      

Fusion de données pour l'estimation des temps de parcours via la théorie de l'évidence

The emergence of new information technologies and the transformation that has occurred in traffic management have both increased drivers' already considerable need for road traffic information. The travel time is one of the forms in which this information is presented, and a number of systems are based on its dissemination. In this context, this indicator is used as a measure of the impedance (or cost) of routes on the network and/or a congestion indicator. This raises the problem of estimating travel times with an acceptable degree of accuracy, which is a particularly difficult task in urban areas as a result of difficultes of a theoretical, technical and methodological nature. Thus, in order to find out the traffic conditions that prevail on an urban road, the traffic sensors that are usually used to measure traffic conditions are ineffective under certain circumstances. New measurement devices (cameras, GPS or cellphone tracking, etc.) mean that other sources of data are increasingly used in order to supplement the information provided by conventional measurement techniques and improve the accuracy of travel) time estimates. As a result, travel time estimation becomes a typical data fusion problem. This study deals with a multisource estimate of journey times and attempts to provide a comprehensive framework for the utilization of multiple data and demonstrate the feasibility of a travel time estimation system based on the fusion of data of several different types. In this case two types of data are involved, data from conventional induction loop sensors (essentially flow and occupancy measurements) and data from probe vehicles. The selected modelling framework is the Dempster-Shafer Evidence Theory, which has the advantage of being able to take account of both the imprecision and uncertainty of the data. The implementation of this methodology has demonstrated that, in each case, better results are achieved with fusion than with methods based on a single source of data and that the quality of the information, as measured by correctly classified rates, improves as the degree of precision required of the estimate is increased.     

北京市典型货车运输链分析研究

通过北京市开展多年的货运车辆抽样调查,总结了北京市搬家运输、混凝土运输、商品配送、油品运输、长途运输等典型货车运输链,分析运输规律,为城市中心区货运需求调查和货运运力配备需求测算奠定了基础.提出了货车运输链描述指标,并且指出要进一步加强信息化技术手段的应用,积极研究利用新技术、新手段,加强货车运输链深入总结归纳,进一步提高相关信息及管理决策的准确性、科学性,充分发挥决策支持功能.     

A novel arterial travel time distribution estimation model and its application to energy/emissions estimation

Arterial travel time information is crucial to advanced traffic management systems and advanced traveler information systems. An effective way to represent this information is the estimation of travel time distribution. In this paper, we develop a modified Gaussian mixture model in order to estimate link travel time distributions along arterial with signalized intersections. The proposed model is applicable to traffic data from either fixed-location sensors or mobile sensors. The model performance is validated using real-world traffic data (more than 1,400 vehicles) collected by the wireless magnetic sensors and digital image recognition in the field. The proposed model shows high potential (i.e., the correction rate are above 0.9) to satisfactorily estimate travel time statistics and classify vehicle stop versus non-stop movements. In addition, the resultant movement classification application can significantly improve the estimation of traffic-related energy and emissions along arterial.     

eTS fuzzy driver model for simultaneous longitudinal and lateral vehicle control

In this paper, evolving Takagi-Sugeno (eTS) fuzzy driver model is proposed for simultaneous lateral and longitudinal control of a vehicle in a test track closed to traffic. The developed eTS fuzzy driver model can capture human operator’s driving expertise for generating desired steering angle, throttle angle and brake pedal command values by processing only information which can be supplied by the vehicle’s on-board control systems in real time. Apart from other fuzzy rule based (FRB) models requiring human expert knowledge or off-line clustering, the developed eTS driver model can adapt itself automatically, even ‘from scratch’, by an on-line learning process using eTS algorithm while human driver is supervising the vehicle. Proposed eTS fuzzy driver model’s on-line human driver identification capability and autonomous vehicle driving performance were evaluated on real road profiles created by digitizing two different intercity express ways of Turkey in IPG© CarMaker® software. The training and validation simulation results demonstrated that eTS fuzzy driver model can be used in product development phase to speed up different tests via realistic simulations. Furthermore eTS fuzzy driver model has an application potential in the field of autonomous driving.     

Characteristic analysis for cognition of dangerous driving using automobile black boxes

Automobile black boxes are devices that collect information regarding vehicle operation and the driver’s operating situation in the case of a traffic accident. The information collected from the automobile black box, which can also be used during normal driving, can provide information about dangerous driving cognition. This study was designed to analyze characteristics of dangerous driving data and build a dangerous driving cognition system as follows. First, dangerous driving is divided into four types by considering the vehicle’s movement, such as acceleration, deceleration, turning and statistical data of traffic accidents. Second, dangerous driving data were collected by vehicle tests using the automobile black box, and characteristics of the driving data were analyzed to classify dangerous driving. Third, a standard threshold was chosen to recognize dangerous driving, and an algorithm of dangerous driving cognition was created. Finally, verification was conducted by vehicle tests with automobile black boxes embedded with the developed algorithm. The presented recognition methods of dangerous driving can be used for on/off-line management of drivers and vehicles. Scientific traffic accident databases can be built with this driving and accident information, and can be used in various industrial areas.     

高速公路突发事件救援车辆诱导

为了提升高速公路突发事件应急救援效率,将交通状况、在途潜在风险等信息纳入高速公路突发事件救援车辆诱导研究中,基于实时和时变路网环境下的交通信息,以车辆出行时间最小,路径可靠性最强为目标,构建基于在途时间和路径可靠性的车辆诱导最优化模型。设计一种实时信息和时变信息结合策略,使模型规划路径随路网交通量变化而相应做出阶段性调整,采用滚动时域策略将该动态决策问题转化为一系列离散时间点的静态决策问题,用于计算应急救援路径时间;在此基础上,考虑到高速公路突发事件发生后路网交通事故率升高,同时容易发生拥堵的状况,进一步将救援规划路径可靠性作为决策目标,即应急救援车辆规划路径在面对道路中断或者严重拥堵时是否拥有更多的调整策略,更新救援路径尽快完成救援任务;为了便于量化计算将上述目标转化为统一的价值成本,共同决定救援车辆的行驶路径。研究结果表明：当行驶路段交叉口间距离较长,中间无其他道路连通,行驶过程中由于突发事件破坏趋势蔓延导致道路中断或拥堵等意外发生时,无法更新调整救援路径,最终导致救援延误;因此,基于救援时间和路径可靠性的车辆诱导最优化模型能够克服以上问题,进一步提高救援效率。     

基于多方式广义费用模型的超级交通网络需求预测技术应用

针对综合交通网络规划各方式缺乏有机融合问题，通过建立以虚拟概化线连接的铁路、公路、水运、民航各方式交通线网和火车站、港口、机场等枢纽节点一体衔接的超级交通网络模型，运用广义费用函数计算客货在路网、枢纽及虚拟概化线上流动产生的广义费用，实现各方式交通网络融合。考虑公路客货运周转量占全方式总量比例高，但客货运平均运距短，以县级行政单元为基础将全国划分为2 540个综合交通小区，获取2018年各运输方式全年客货运起讫点（OD）数据，通过聚合、拆分等方法，将各方式OD表叠加形成现状综合交通小区客货运输量OD表；采用总量预测、自上而下分层控制的技术路线，对2050年全国总量、分区域总量和综合交通小区客货运发生吸引量进行预测，计算2050年综合交通小区客货运输量OD，实现各方式运输需求融合。基于Fisk模型，构建组合出行情况下多方式、多类别随机用户均衡分配模型（SUE），采用连续权重平均（MSWA）法对模型进行求解，并通过算例验证了模型和算法的有效性。结果表明：模型能够体现“宜铁则铁、宜公则公、宜水则水”的规划理念，实现乘客组合出行和货物多式联运，预测精度较高。研究成果可应用于宏观交通趋势判断，为实现综合交通网络规划中各方式有机融合提供借鉴，并成功应用于国家综合立体交通网规划研究中。     

高速公路运输量研究

提出了高速公路运输量的统计方法,并以南京—上海高速公路为例,首次统计了中国高速公路的客运量、货运量、客运周转量、货运周转量以及客、货运输密度。研究表明:在南京—上海通道内,高速公路和铁路起着同样的关键作用;货运方面,高速公路和铁路运送货物价值相差很大,两者是互补性的,客运方面,高速公路客运量中个性化出行与铁路是互补性的,而群体性出行与铁路是替代性的。对高速公路上运行的车辆状况进行了分析,指出货运量主要是由四轴的半挂列车和两轴的单车完成的。客运中个性化出行的乘客占40%,车数占88%。     

Multi-objective optimal predictive control of signals in urban traffic network

Traffic congestion in urban network has been a serious problem for decades. In this paper, a novel dynamic multi-objective optimization method for designing predictive controls of network signals is proposed. The popular cell transmission model (CTM) is used for traffic prediction. Two network models are considered, i.e., simple network which captures basic macroscopic traffic characteristics and advanced network that further considers vehicle turning and different traveling routes between origins and destinations. A network signal predictive control algorithm is developed for online multi-objective optimization. A variety of objectives are considered such as system throughput, vehicle delay, intersection crossing volume, and spillbacks. The genetic algorithm (GA) is applied to solve the optimization problem. Three example networks with different complexities are studied. It is observed that the optimal traffic performance can be achieved by the dynamic control in different situations. The influence of the objective selection on short-term and long-term network benefits is studied. With the help of parallel computing, the proposed method can be implemented in real time and is promising to improve the performance of real traffic network.     

Improved Speed Estimation From Single-Loop Detectors With High Truck Flow

Single-loop detectors are the most common sensors employed by freeway traffic management agencies. The data are used for traffic management and traveler information. Single-loop detectors can only measure flow and occupancy. Although speed is often the most useful metric, it can only be estimated at conventional single-loop detectors. Typically this estimate comes from the quotient of flow and occupancy multiplied by the fixed, assumed average effective vehicle length. This conventional approach is limited because the actual average effective vehicle length will vary from sample to sample. Many researchers have proposed alternatives to address this problem, and although many of the methods work well under normal conditions, there has been limited research into methods that yield reliable estimates under heavy truck traffic. Heavy truck flows may arise as a function of location or time of day, for example, with proximity to a trucking facility or in early mornings when the number of passenger vehicles drops, respectively. This article presents a new methodology to estimate speed from single-loop detectors in conditions where trucks comprise a large percentage of the fleet. While the focus is on single loop detectors, the work is equally applicable to side-fire microwave radar detectors that emulate single-loop detectors.     

基于车辆轴型分类的公路货运车辆运营成本研究

针对目前公路货运车辆运营成本分析中车型分类与装载量确定方法的不足,提出了基于车辆轴型分类的运营成本研究模式,在按轴型划分的交通量和轴载调查的基础上通过建立轴载分布模型确定分析车型与其装载量,并根据政府政策和车辆装载量的影响程度分类统计分析车型的单位运营成本。使用安徽省调查数据推导出了公路货运车辆运营成本与装载量之间的经验公式。结果表明:该省公路货运车辆的平均单位运营成本在0.253-0.756元/t·km之间,与市场运价基本一致。     

基于船舶AIS及签证数据的长江内河货运阻抗及分布模型研究

为了研究长江内河各航段复杂多变的航道环境对水路货物运输的影响,根据船舶AIS数据及三峡船闸过闸数据建立一种考虑不同月份、不同航段的船舶逆水而上、顺流而下2种情况的货运阻抗函数,并基于Matlab求解得到长江内河重要港口节点之间不同月份的时间阻抗矩阵.以2010年10月船舶签证数据为例,结合距离阻抗矩阵和时间阻抗矩阵,标定阻抗函数为幂函数和指数函数下的重力模型的参数,建立相应的货运分布模型.并在不同模型下分别预测了2012年10月货运量分布情况.对货运实际观测值和模型预测值结果进行货运距离分布(trip length distribution,TLD)方法检验.结果显示,以时间为阻抗指标的幂函数和指数函数重力模型预测结果的重合率(coincidence ratios,CR)值分别为0.83和0.86,比对应的以距离为阻抗指标的预测结果的CR值0.81和0.82要高,所建立的以时间阻抗模型更能反映长江内河货运实际情况.      

信号交叉口右转机动车与行人和非机动车冲突研究

研究的主要内容为:未设置右转专用相位的信号灯控制道路交叉口右转机动车流与行人和非机动车的冲突行为,包括冲突数据的采集和提取、右转车流受到干扰前后速度与过街时间对比分析以及机非冲突速度-距离模型。以现实交通数据为基础,通过软件提取右转机动车与行人和非机动车冲突数据,建立标准统一的冲突数据库,以此为基础对比分析右转车流正常行驶状态和受到干扰情况下通过道路交叉口时的车速和过街时间,并建立右转车辆距离机非冲突点不同位置时所对应不同速度的统计模型。研究结果对右转专用相位设立标准的建立和相应信号配时方案的设计具有一定的工程指导意义。     

区域综合货运OD推算方法及信息价值研究

结合区域公路、铁路货运的特点,对可获取的多来源信息进行了分析,并用于基年货运OD矩阵的推算.建立了基于模糊规划理论的多源数据OD推算模型及算法,并通过江苏省综合货运OD推算的实例对多源信息的信息价值进行了分析,用于反馈指导多源信息的进一步收集.结果表明,模糊数学的引入有助于解决多源数据带来的不确定性问题,提高OD推算精度.另一方面,路段流量、子区域OD量,以及集计OD量的数值价值相对较大,而且路段流量当中,高流量数据较随机流量数价值更高.     

基于提取PMP控制规则的FCHEV能量管理策略

针对FCHEV的能量管理问题,提出一种基于提取PMP控制规则的FCHEV能量管理策略.利用PMP优化算法解出的车辆在CHTC_C工况下离线最优控制序列,从最优控制序列中提取控制规则,实现能量管理策略的在线化.在MATLAB/Simulink上建立车辆模型,对所提能量管理策略进行仿真验证.仿真结果表明:所提能量管理策略能...     

车辆轴限对钢筋混凝土桥梁可靠度和加固费用的影响

为了分析车辆限载对钢筋混凝土桥梁可靠度和加固费用的影响,基于实测车辆动态称重数据和可靠度理论,研究了桥梁可靠度及其年均加固费用与车辆轴限值的关系。首先根据车辆动态称重数据统计得到交通荷载资料,在保持车货运输总重不变的前提下,采用蒙特卡罗法模拟不同轴限值约束下的随机车流。然后,计算桥梁在不同轴限值下的时变可靠度,结合不同加固方案所引起的可靠指标变化确定桥梁剩余使用寿命及其年均加固费用,并拟合确定轴限值与年均加固费用的关系曲线。最后,以湖南某地区的实测车辆动态称重数据及一座典型的钢筋混凝土简支T梁桥为例进行分析说明。研究结果表明：对桥梁进行限载可以减缓桥梁可靠指标的下降速率;在车货运输总重保持不变的条件下,轴限值越大,桥梁的可靠指标下降越快,桥梁使用寿命越短;当轴限值不超过10 t时,桥梁使用寿命可以达到设计使用年限,而当轴限值超过16 t后,桥梁结构的可靠指标随时间下降明显,在达到设计使用年限之前需要采取加固措施;采用3种常见的方案对桥梁进行加固后,桥梁剩余使用寿命随轴限值的增加均呈明显的下降趋势;随着轴限值继续增大,3种加固方案对桥梁剩余使用寿命的影响越来越小,而桥梁年均加固费用却随轴限值的增大呈指数型增长。