面向车辆行驶过程的舒适性评价指标体系

从机动车行车过程的舒适性角度出发,介绍了车辆行驶舒适性概念,通过分析单个车辆的行驶状态突变特征,构建了面向车辆行驶过程的适用于城市道路的舒适性评价指标体系。     

混合交通流条件下基于路内停车设置的路段车速阻滞模型

提出机非混合交通流条件下路内停车带设置后的机动车速阻滞模型。以一幅道路断面形式为前提,将混合交通和车辆停放的驶入、驶出对路段车流运行状态的影响表述为摩擦和阻滞效应,引入时间障碍率和空间障碍率参数加以量化分析,选择6条典型路段进行数据调查,在验证基本路阻函数可行性的基础上,分别建立路内停车摩擦效应和阻滞效应影响下的机动车速度-交通流模型。针对模型参数的复杂性特点,设计参数指标聚类和分阶段标定方法,并对一幅道路单向通行和双向通行的相关模型进行具体参数的计算。将实测数据和模型计算结果进行对比可以发现,整体拟合效果良好,能够反映混合交通流条件下路内停车设置对机动车交通运行的实际状态。     

城市信号交叉口人行横道通行能力研究

通过对交叉口过街混合交通流过街特性、过街需求、过街效率指标的分析,得到了人行横道混合交通流相对于行人的通用折算方法,同时提出一种针对我国人行横道交通特征计算行人通行能力的新方法,具有一定的实用价值。     

论混合交通的危害与对策

现阶段在我国，混合交通一般有三种情况：一是在单幅路上通行不同类型的机动车辆；二是在一条道路上不但行驶不同类型的机动车，同时还行驶着各种类型的非机动车辆；三是指在城市某些支路上行驶着机动车、非机动车和行人。我们一般所指的混合交通是后两二种。目前我国城市道路绝大多数都是混合交通，交通秩序非常混乱，交通事故急剧增加，城市环境不断恶化，运输效益下降，因此，如何从道路建设，整顿交通秩序，科学交通管理，加强交通安全教育等措施来改善混合交通具有十分重要意义。1混合交通所产生的危害1．1交通秩序更加混乱混合交通本…     

城市道路交通分析

城市道路是城市交通的重要基础设施,通过对城市道路交通中人、车辆、道路以及交通流的特性为基础,本文分析了城市道路交通的交通功能、需求、安全性以及环境,提出了城市道路交通设计的相关政策、基本原则和技术路线。     

大型车比例对城市道路机动车速度-流量模型的影响分析

交通流组成中的大型车比例是城市道路机动车速度-流量关系建模的重要影响因素,以往研究成果对此考虑不够。以四幅路和三幅路为对象,在大量实测数据基础上采用双因素方差分析法表明机动车流量和大型车比例均对车流速度产生显著影响。由BPR模型拓展得到各类道路速度-流量模型的通用形式,进而利用实测数据从统计学角度进行变量筛选和参数标定,最终建立各类道路不同大型车比例下的机动车速度-流量模型。该模型既可服务于宏观交通流分析,又可以为制定城市道路大型车限行或分流措施等提供参考。     

对城市道路设计中几个问题的思考

对城市道路设计中存在的忽视交通分析、缺乏自主创新与灵活性以及无障碍设计、机动车设计车辆尺寸、机动车车道宽度等问题进行了研究和思考,以期设计工作早日适应新形势的需要。     

城市道路中转弯情况下的拐点补传触发条件

研究车辆行驶状况通常引入车辆轨迹回放,即车辆在行驶过程中所经过的路线,其包含了所走过的每一个GPS卫星数据点。然而,车辆行驶在城市道路中所面临的是弯道直路交错的复杂路况。因此,当行驶速度较快时,将出现一些弯道的轨迹被拉成直线的问题,影响研究数据。因此,需要在弯道和直路交叉变换等复杂路况拐点补传,论文针对城市道路弯道中的拐点补传触发条件进行研究。     

楚雄市城市道路交通现状及对策研究

基于文献阅读、资料查询、实地调查等,对道路网现状、车辆保有量现状、道路交通流构成对楚雄市城市道路交通现状进行了研究,研究表明目前楚雄市城市道路交通存在人车混行严重,车多路窄、行车困难等问题,最后针对这些问题提出了相应的对策。     

也谈对超重货运车辆的认定与处理——与苏云利同志商榷

《城建监察》杂志2004年第11期上发表了烟台市城管执法支队苏云利同志《对行驶在城市道路上的货运车辆的超重如何认定》一，该在对行驶在城市道路上超重的货运车辆的认定上叙述了两种不同意见后，又对超重的货运车辆提出了“如果查获的货运车辆既超出该车的载质量，又超出该路段的承重标准，我们(指城管执法部门，笔注)即可按照国务院《城市道路管理条例》第四十二条之规定对其进行处罚。     

Effect of Pulse‐and‐Glide Strategy on Traffic Flow for a Platoon of Mixed Automated and Manually Driven Vehicles

The fuel consumption of ground vehicles is significantly affected by how they are driven. The fuel‐optimized vehicular automation technique can improve fuel economy for the host vehicle, but their effectiveness on a platoon of vehicles is still unknown. This article studies the performance of a well‐known fuel‐optimized vehicle automation strategy, i.e., Pulse‐and‐Glide (PnG) operation, on traffic smoothness and fuel economy in a mixed traffic flow. The mixed traffic flow is assumed to be a single‐lane highway on flat road consisting of both driverless and manually driven vehicles. The driverless vehicles are equipped with fuel economy‐oriented automated controller using the PnG strategy. The manually driven vehicles are simulated using the Intelligent Driver Models (IDM) to mimic the average car‐following behavior of human drivers in naturalistic traffics. A series of simulations are conducted with three scenarios, i.e., a single car, a car section, and a car platoon. The simulation results show that the PnG strategy can significantly improve the fuel economy of individual vehicles. For traffic flows, the fuel economy and traffic smoothness vary significantly under the PnG strategy.     

基于WIM的典型城市桥梁车辆荷载状况分析

基于安装在杭州石祥路留石高架上的动态称重系统（WIM）采集的交通流和车辆荷载数据,通过对交通流量、车辆构成、轴重、车辆总重等进行分析,获取了其概率统计特性及分布规律,建立了轴载谱和车辆总重谱,并与相关文献、规范进行了比较。结果表明：一天中各时段的交通流量具有很强的潮汐规律性;2.86%的车辆轴重超过了10 t的超载标准,最大的单轴重量达39.5 t,最大车辆总重达115 t,后半夜车辆恶性超载严重;2轴车车辆总重表现为单峰分布,3轴以上车辆的总重均表现为多峰分布,5轴车和6轴车的总重表现为3峰分布;轴重大的车辆主要是超载的2轴、3轴车辆,这部分车辆对桥梁等基础设施的危害较大。这些车辆荷载特征的获取有助于区域既有桥梁安全性的合理评估,为超重车辆治理和桥梁安全管理提供帮助。     

Modelling instantaneous traffic emission and the influence of traffic speed limits

This paper considers the effect of active speed management on traffic-induced emissions. In particular, the traffic emissions caused by acceleration and deceleration of vehicles are modelled based on an instantaneous emission model integrated with a microscopic traffic simulation model. The emission model is based on empirical measurements which relate vehicle emission to the type, the instantaneous speed and acceleration of the vehicle. The traffic model captures the second-by-second speed and acceleration of individual vehicles travelling in a road network based on their individual driving style, the vehicle mechanics, and their interaction with other traffic and with traffic control in the network. The integrated model is applied to test a new technology to actively manage the driving speed of the vehicles in an urban network. Their impacts on vehicle emission in the network are assessed to give an indication of the relative effectiveness of the different technological designs and different levels of driver responses. The results show that, while the speed management has effectively reduced the average speed of the traffic, their impact on vehicle emissions is complex. For the study network, the frequent acceleration and deceleration movements in the network has significantly reduced the effect of the reduced average speed on emission. The net results are that the active speed management has no significant impact on pollutant emissions. The study suggests that the analysis of the environmental impacts of any traffic management and control policies is a complex issue and requires detailed analysis of not only their impact on average speeds but also on other aspects of vehicle operation such as acceleration and deceleration.     

Detecting and tracking vehicles in traffic by unmanned aerial vehicles

Using unmanned aerial vehicles (UAV) as devices for traffic data collection exhibits many advantages in collecting traffic information. This paper introduces a new vehicle detecting and tracking system based on image data collected by UAV. This system uses consecutive frames to generate vehicle's dynamic information, such as positions and velocities. Four major modules have been developed: image registration, image feature extraction, vehicle shape detecting, and vehicle tracking. Some unique features have been introduced into this system to customize the vehicle and traffic flow and to jointly use them in multiple consecutive images to increase the system accuracy of detecting and tracking vehicles. Field tests demonstrate that the present system exhibits high accuracy in traffic information acquisition at different UAV altitudes with different view scopes, which can be used in future traffic monitoring and control in metropolitan areas.     

城市道路桥梁的疲劳荷载谱

我国针对公路及城市道路桥梁疲劳设计的车辆荷载谱还是个空白,本文以上海市内环线中山路3号桥地面道路桥梁为例,对城市道路桥梁的疲劳荷载作了研讨.在1994年和1995年两次交通调查的基础上,得到了由18类日常典型的运营车辆组成的荷载频值谱.依据等效的疲劳损伤原理,将实测的车辆荷载频值谱简化成由6类模型车辆组成的具有实用性的荷载频值谱.所建立的模型车辆荷载频值谱,对于日常车辆交通构成与本文状况相类似的其它城市道路桥梁的疲劳损伤度验算,可作为参考.     

Lossless Compression of All Vehicle Trajectories in a Common Roadway Segment

This article describes a method for compressing position and identification data for files containing comprehensive trajectory records of all vehicles traversing the same roadway segment over an arbitrary time period, in such a way that no loss of information content occurs. Such complete trajectory records are important for the study of traffic flow theory and could become increasingly relevant as test data against which to study the behavior of autonomous vehicles in a mixed traffic environment. Compression steps include differential encoding, motion prediction, and parsimonious binary storage, plus steps that are unique to the context of vehicle trajectories, including vehicle ID numbers and lane occupancy. The effectiveness of the compression is due, in part, to the strong correlations between positions (and speeds) of vehicles traveling near each other, as well as recognition that certain trajectory artifacts change with spatial and temporal frequencies much lower than the sampling rates. The algorithm is demonstrated on two sets of publicly available complete trajectory records, and compression performance statistics are given. Compression ratios in the range 10:1 to more than 20:1 are achieved for the sample files.     

Signal timing at an isolated intersection under mixed traffic environment with self-organizing connected and automated vehicles

This study provides a signal timing model for isolated intersections under the mixed traffic environment consisting of connected and human-driven vehicles (CHVs) and connected and automated vehicles (CAVs). Different from existing studies, CAVs are not controlled by traffic controllers and conduct trajectory planning themselves, which are called self-organizing CAVs (SOCAVs). The specific trajectory planning strategies of SOCAVs are not accessible to traffic controllers either. The signal optimization problem is formulated as a mixed integer linear programming (MILP) model for total vehicle delay minimization. The states of SOCAVs and CHVs passing the stop bar are predicted without prior information of the trajectory planning strategies of SOCAVs. SOCAVs can lead approaching platoons to pass the intersection effectively, and such “leading effects” of SOCAVs are utilized. Phase sequence and duration are optimized with the “structure-free” phasing scheme. A parallel particle swarm optimization algorithm with a grouping strategy is designed to solve the optimization model at a reduced scale for computational efficiency. Numerical studies validate that (1) the proposed algorithm significantly outperforms the benchmark method, which directly solves the proposed MILP model using the solver Gurobi 9.0, under medium and high traffic demand; and (2) the proposed model significantly outperforms fixed-time and vehicle-actuated signal control in terms of vehicle delay and throughput. Sensitivity analysis shows that the SOCAV penetration rate of 30% is sufficient to guarantee satisfactory performance of the proposed signal timing model.     

车辆荷载作用下高速公路路基路面动力研究

车辆与道路之间动荷载问题是一个非常复杂的相互过程,在充分考虑振动荷载产生机理的基础上,从车辆荷载的重要形式、车辆荷载的模拟、路基有限元模型的建立等方面,研究了路面在车辆动载作用下的动态响应特征。     

道路平面交叉口次路远引几何参数设置及通行效率研究

次要车流的左转和直行对交叉口车辆运行影响较大,特别是主路交通流量较大时尤为明显,通过次要道路车流远引的方式可以减少交叉口车辆冲突,有利于提高交叉口运行效率。分析了平面交叉口次路远引适用条件与车流组织方法,以延误最小为目标,构建了远引回转车流掉头位置、远引车辆掉头排队车道长度、远引掉头处开口长度与宽度等关键几何参数计算模型,提出了次路远引交叉口延误和通行能力等计算方法。结合实例验证了上述方法的可行性,仿真显示,在一定条件下平面交叉口次路远引可有效减少信号相位数和车辆平均延误,表明了平面交叉口次路远引的交通组织方法对优化城市道路交叉口设计有较好的应用价值。     

对我国城市混合交通问题的思考

剖析了我国城市机动车与非机动车混合交通的形成原因及混合交通所带来的交通问题,通过对道路交叉口和路网交通组织规律的分析,提出了构建机非路网分流体系的基本思路和今后研究的重点.