城市地下快速路驾驶模拟仿真试验方法研究

城市地下快速路具有设计指标宽容性低、多点进出、交通组织复杂等特点。针对待建的城市地下快速路,如何通过科学的方法获取地下快速路车辆运行数据是当前研究的难点。首先,结合城市地下快速路BIM模型,介绍高逼真驾驶模拟场景搭建过程及常见问题解决方法;随后,针对试验行驶路径、交通流量等要素制订驾驶模拟试验方案;最后,计算合理的试验样本数,利用试验获得的数据,提出驾驶模拟数据分析流程与方法。为了充分探究驾驶模拟仿真试验设计方法,通过驾驶模拟手段获得城市地下快速路驾驶行为数据,可为地下快速路驾驶行为特性研究、安全性评价及运营管理策略制订提供支撑。     

关于城市快速路出入口间距的研究

城市快速路作为长距离、大容量的通过性道路,兼顾了服务地块功能,是缓解交通瓶颈、提升整体路网服务水平、提高人均道路占有率的利器.为保证快速路交通功能的充分发挥,合理控制出入口间距、降低出入口范围的交通延误显得尤为重要.通过查阅相关规范,发现城市快速路对于出入口间距的要求与公路存在一定差异性.该文针对城市快速路出、入口最小间距展开研究,结合公路规范要求及计算模型,通过分析城市快速路与公路的差异性,提出了减小城市快速路连续出、入口对主线交通流影响的建议,可对今后快速路的设计、运营及管理提供参考.     

公路隧道交通拥堵疏散决策技术研究

针对公路隧道发生事故后交通拥堵疏散问题,结合隧道事故等级、事故处理时间、车辆行驶速度,引入交通流、交通波模型,依托重庆某特长公路隧道实际交通量数据,建立公路隧道交通拥堵疏散决策模型,分析公路隧道交通拥堵状态下的疏散控制,通过实例计算和模型仿真,验证了模型的准确性和适用性。结果表明:公路隧道交通拥堵疏散决策模型可非常准确地预判隧道发生各级事故后交通拥堵时间、排队长度等交通特征,依托模型预测结果,可快速制定高效交通诱导方案,实现交通管控和疏散,让公路隧道及所属路段快速恢复高效运行,为公路隧道的安全、高效运营管理提供决策支持。     

路网容量法在城市用地与交通规划宏观分析中的应用

路网容量法包括路网设计容量法和路网实际容量法两种计算模型,后者还包括区域路网实际容量计算模型和城市总路网实际容量计算模型.路网容量法是进行城市及区域用地、交通方面宏观分析研究的一种方便、有效的理论方法.通过路网容量计算,可进行路网服务水平评价、交通模式研究、人口及机动车发展规模测算、城市用地与交通规划调整.     

MATLAB在结构状态预测中的应用

结构的输出数据能从一定程度上反映结构的状态,而输出数据是一段时间序列,通过对时间序列的分析,也就能够得到结构的状态信息.首先叙述了MATLAB的语言特点和时间序列模型的建模过程,然后给出了利用MATLAB系统辨识工具箱进行建模和预测的方法和步骤,最后对一段模拟数据建立AR模型并进行数据预测,结果说明该方法对于系统状态的预测是可行的.     

基于因子分析与改进K-means聚类的交通状态判别

为了提高城市快速路交通运行状态判别的精确度,提出一种基于因子分析与改进K-means聚类的城市快速路交通状态判别方法。首先运用因子分析对流量、速度、占有率、密度、行程时间、饱和度、占有率/流量、占有率/速度等8个交通流参数进行了相关性分析及适用性检验,提取了流量、速度和占有率/速度3个交通状态判别指标;其次通过建立交通状态综合评价函数对K-means聚类算法进行改进,将快速路交通状态聚簇为4类;最后使用快速路的实测数据完成算法的实例验证和对比分析。结果表明,基于因子分析与改进Kmeans聚类算法的快速路交通状态判别率为97.21%,误判率为0.74%,相对于传统K-means聚类算法判别精度提高了8.13%,误判率降低了1.05%。     

城市快速路交通组织设计思路研究

结合蚌埠市中环线工程交通组织设计实例,探讨了城市快速路交通组织设计中的要点和关键,包括功能定位,设计原则,设计思路等内容,以期科学合理设计城市快速路,有效缓解路网拥堵现状。     

业界动态

<正>上海整合交通监控系统平台日前,"公路网交通监控系统和城市快速路交通监控系统应用平台整合完善工程"项目通过上海市交通指挥中心验收。为适应机构管理体制改革和路网一体化管理的需要,该工程计划在已建成的两个监控中心、两套交通监控系统的基础上,建立面向全路网统一的业务平台和基础资源库;构建面向高速公路、城市快速路、虹桥枢纽、普通国省干线公路等全路网的一体化交通运行监测业务管理平台;调整优化两个监控中心主干通信网络,并适应数字高清     

基于“服务水平”概念的路网总体容量计算模型

引入"路网服务水平"概念,建立不同路网服务水平条件下的交通网络总体容量计算模型;根据交通流基本参数速度—流量—密度之间的基本关系,建立不同服务水平下各级道路的车流密度计算模型;进而确定道路交通网络系统所能承受的车辆数以及交通系统所能适应的交通需求总量,并结合青岛市城市综合交通规划,给出了路网容量计算实例.     

上海市快速路(高架)系统交通路网的配套研究

针对目前上海市快速路系统交通路网存在的突出问题,从整个路网结构出发,提出充分挖掘高架系统配套路网的交通潜力,采用建立主干路机动车专用路网、配套非机动车通道路网、主干路交叉口整治和渠化等手段,增加交通疏解能力,缓解高架快速路系统日益增加的交通压力。     

突发事件下城市快速路网分流模型研究

通过对城市快速路网中突发事件路段的研究,建立了事件路段的分流模型,根据事件延误与绕行延误的关系,决定是否诱导出行者使用最短路径进行分流,从而有助于出行者选取最佳分流路径,减少因路网事件而造成的交通延误。     

A Dynamic Route Choice Model Considering Uncertain Capacities

Abstract: The standard assumption in (dynamic) traffic assignment models is that route choice is solely determined by a (perceived) deterministic travel time. However, recently, there is a growing interest in (dynamic) equilibrium route choice models in which travelers not only select their paths based on an estimated deterministic travel time, but also based on travel time reliability, in this article defined as the probability that the actual travel time deviates from the anticipated value. We extend the linear programming cell transmission model‐based dynamic traffic assignment (LP CTM‐DTA) model to account for travelers’ consideration of uncertainty regarding saturation flow rates (in this article referred to as capacities). It is shown that these reliability considerations can be accounted for by simply reducing the road capacities appearing in the constraint set of the classical LP CTM‐DTA model. More importantly, we provide results on the amount of capacity reduction necessary to ensure a certain reliability level. Although in the proposed model any probability distribution can be used to model the uncertainty, the selection of a specific probability distribution can potentially be burdensome for the modeler. To this end, we also present results on the class of symmetric probability distributions that has been particularly popular in the robust optimization literature. Properties for this broad class of distributions will be derived within the context of the introduced model. In numerical case studies, the model predicts that travel patterns can be significantly different when accounting for travelers’ reliability considerations.     

上海市高架道路宏观稳态交通流建模及应用

利用宏观交通流模型对高架道路的运行状况进行了评价。在模型的选择上包括三个基本模型:递推模型、起始—到达模型、起始—终点模型。利用递推模型分析了上海市中心城区高架道路交通流状态。并与实际运行情况基本吻合。可见模型从宏观层次上能充分反映高架交通流随时间和空间的变化及分布规律,从而分析、评价了高架道路各路段的交通运行状态,指出了高架道路的交通瓶颈所在。     

Methodology for spatio‐temporal predictions of traffic counts across an urban road network and generation of an on‐road greenhouse gas emission inventory

On‐road emission inventories in urban areas have typically been developed using traffic data derived from travel demand models. These approaches tend to underestimate emissions because they often only incorporate data on household travel, not including commercial vehicle movements, taxis, ride hailing services, and other trips typically underreported within travel surveys. In contrast, traffic counts embed all types of on‐road vehicles; however, they are only conducted at selected locations in an urban area. Traffic counts are typically spatially correlated, which enables the development of methods that can interpolate traffic data at selected monitoring stations across an urban road network and in turn develop emission estimates. This paper presents a new and universal methodology designed to use traffic count data for the prediction of periodic and annual volumes as well as greenhouse gas emissions at the level of each individual roadway and for multiple years across a large road network. The methodology relies on the data collected and the spatio‐temporal relationships between traffic counts at various stations; it recognizes patterns in the data and identifies locations with similar trends. Traffic volumes and emissions prediction can be made even on roads where no count data exist. Data from the City of Toronto traffic count program were used to validate the output of various algorithms, indicating robust model performance, even in areas with limited data.     

A Bayesian mixture model for short-term average link travel time estimation using large-scale limited information trip-based data

Accurate estimation and prediction of urban link travel times are important for urban traffic operations and management. This paper develops a Bayesian mixture model to estimate short-term average urban link travel times using large-scale trip-based data with partial information. Unlike typical GPS trajectory data, trip-based data from taxies or other sources provide limited trip level information, which only contains the trip origin and destination locations, trip travel times and distances, etc. The focus of this study is to develop a robust probabilistic short-term average link travel time estimation model and demonstrate the feasibility of estimating network conditions using large-scale trip level information. In the model, the path taken by each trip is considered as latent and modeled using a multinomial logit distribution. The observed trip data given the possible path set and the mean and variance of the average link travel times can thus be characterized using a finite mixture distribution. A transition model is also introduced to serve as an informative prior that captures the temporal and spatial dependencies of link travel times. A solution approach based on the expectation–maximization (EM) algorithm is proposed to solve the problem. The model is tested on estimating the mean and variance of the average link travel times for 30 min time intervals using a large-scale taxi trip dataset from New York City. More robust estimation results are obtained owing to the adoption of the Bayesian framework.     

城市交通网络设计问题中的双层规划模型

城市交通网络设计问题的主要内容就是通过规划的思想建立数学模型,通过优化计算方法寻找最优的用于道路网络新建或改善的交通建设投资决策方案,即研究如何能用最少的资金投入达到使整个交通网络中某种指标最优的目的。这些具体的系统性能指标可以是使整个网络中的系统总阻抗最小、交通拥挤程度最低、能源消耗最少等,从而为交通规划部门和决策人员提供科学、系统、合理、有效的决策方案和决策数据,使政府有限的资金投入能取得最佳的投资效益。本文首先简单介绍了城市交通网络设计问题研究的主要内容,然后给出了城市交通网络设计中一般形式的双层规划模型及其推广形式。     

An optimization‐based traffic diversion model during construction closures

During major highway construction, when lanes or entire highway sections must be temporarily closed, traffic managers would like to inform motorists of alternative routes around the construction site well in advance of the project location. This study develops a traffic diversion model to propose an optimum alternate route to drivers during a construction activity. The models and algorithms developed in this study assess a potential diversion route to optimize network performance while considering the drivers’ behaviors in following the proposed alternate route during a closure. A bilevel optimization model is proposed to minimize the total travel time of the affected network considering the link closure and a proposed alternate route for the travelers. A travelers’ route choice decision is modeled based on the user equilibrium traffic assignment, whereas a certain percentage of drivers are assumed to divert to the recommended alternate route. A sufficiently large subnetwork is selected, and a path selection method is proposed to reduce the computational effort required to optimize the model. A set of simulation experiments is conducted using the Tarrant County network in north Texas. The results show the ability of the model to improve the overall network performance during hypothetical closure scenarios.     

宝鸡市道路几何网络模型研究

本文主要是结合MapGIS6.5软件对宝鸡市道路网进行网络分析,进而在此基础上对该系统进行二次开发,建立道路网数据库,为宝鸡市的城市建设、交通规划以及道路管理提供空间数据;同时也为人们的旅游出行等提供方便;更为智能交通和"数字宝鸡"的建设提供地理空间基础框架数据.通过对宝鸡市几何道路模型的研究,探索出一条适合中小城市空间信息应用和地理数据资源集成共享的模式与解决方案.     

双层轿厢电梯运行周期参数研究进展

指出电梯运行周期和电梯种类、服务方式、运行模式有关．主要由电梯可能停站数决定。用统计方法给出双层轿厢电梯在单层运行．准双层运行和双层运行模式下．在有．无层间交通时的可能停站数表示．给出电梯运行周期表示式．并举例说明。这对于双层轿厢电梯和多轿厢电梯系统的交通配置应用研究有推进作用。