基于贝叶斯网络模型的交通状态预测

城市的交通状态是可以预测的.有效的交通状态预测能从很大程度上优化交通状态,减少交通阻塞.贝叶斯网络(Bayesian Networks,BN)是目前不确定知识和推理领域最有效的理论模型之一.提出了一种基于贝叶斯网络模型理论的交通状态预测方法.综合考虑交通阻塞成因的基础上构建网络模型,在已有的交通状态数据的基础上提出基于贝叶斯法则的学习算法,并通过计算变量间的条件概率来计算交通阻塞发生的可能性,达到预测的目的.     

基于聚类分析的交叉口状态识别方法

针对城市交叉口交通状态有效识别的问题,建立了三种交叉口交通状态识别方法。结合实际交通流数据,利用模糊聚类传递闭包法、K均值聚类算法和模糊C均值聚类算法对交叉口交通流周期平均速度、排队长、平均车头时距等向量进行聚类分析,给出适合城市交叉口交通流特点的交通状态划分方法,能够实时、准确、全面地识别城市交叉口的运行状态,为城市交通管理部门交通控制、交通诱导、交通指挥等提供数据基础。定性定量分析的影响,所得结论对城市道路路内停车设施优化具有重要的参考作用。     

基于贝叶斯网络模型的交通状态预测

城市的交通状态是可以预测的。有效的交通状态预测能优化交通状态,减少交通阻塞。贝叶斯网络(Bayesian Networks,BN)是目前不确定知识和推理领域最有效的理论模型之一。文章在综合考虑交通阻塞成因的基础上构建网络模型,在已有的交通状态数据的基础上提出基于贝叶斯法则的学习算法,并通过计算变量间的条件概率来计算交通阻塞发生的可能性,达到预测的目的。     

交通现代化指标体系的基本框架

本文提出交通设施设备现代化、交通运营管理现代化、交通制度现代化和交通可持续、交通意识现代化等四个综合交通现代化总体目标,初步探讨了由总体目标层、功能状态层和要素变量层构成的三层次综合交通现代化指标体系。     

基于交通大数据的动态交通状态预测及全局路径规划研究

为提高动态交通状态预测的准确性,对基于交通大数据的动态交通状态预测及全局路径规划进行研究。以交通大数据为基础,获取指定路段的属性信息与采集信息,通过对样本数据进行描述,得到该路段的试验数据。在具体的预测和分析阶段,构建基于交通大数据的预测模型,实现对动态交通状态的可靠预测。试验结果表明,时间特征值对交通流量的影响较大,某一时间段的交通状态数据可为全局路径规划提供数据源,有利于相关人员作出科学决策,可更好地满足当前智慧交通管理新需求。     

城市路网连贯流交通信号控制策略研究

为了从路网整体战略角度出发考虑不同的交通状态针对性的设计信号控制方案,本文在未饱和状态"连续流"绿波的基础上,提出了"连贯流"交通的概念,分别针对准饱和、过饱和状态提出了连贯流信号控制方法。首先提出连贯流的概念,对其交通特性进行分析,并提出相应的控制目标;然后分别针对准饱和、过饱和状态提出了连贯流信号协调控制方法、连贯流边界信号控制以及连贯流信号疏导方法,建立了一套区域连贯流交通信号协调控制方法体系。     

后疫情时期城市轨道交通客流特征与韧性探讨

在新冠疫情防范常态化的后疫情阶段，城市轨道交通系统频繁受到疫情的影响，提高城市轨道交通系统韧性具有重要意义。本文结合上海市轨道交通疫情及后疫情期间客流量数据，通过使用LSTM模型量化疫情对城市轨道交通系统的影响，验证了城市相关管控策略对轨道系统韧性具有明显影响，提供合理的管控策略对提高城市交通系统韧性具有重要意义。本文结合城市交通韧性理论和交通系统在疫情期间各阶段状态，提出了城市轨道交通韧性治理的相关对策及建议，为疫情防范常态化阶段提高城市轨道交通韧性和精准管控提供参考。     

城市交通需求管理的必要性及政策建议

交通需求管理(TDM)政策通过合理调节和科学引导交通需求,使道路交通资源得到有效利用,交通系统的供需维持在较稳定的动态均衡状态。国际上已经有许多城市通过实施有效的交通需求管理政策缓解交通拥堵,收到很好的效果。我国的很多大城市尤其是特大型城市近年来社会经济快速发展,机动化进程加快,同时面临着资源紧缺和交通拥堵频发的形势,本文论述了在我国大城市实施交通需求管理的必要性和可行性,在此基础上,以北京市为例,提出了当前实施交通需求管理政策的相关建议。     

北京奥运会交通运行组织与管理的经验分析

北京奥运会是一次非常成功的大型国际赛事,其交通组织管理经验对国际大型体育比赛项目的交通组织与管理具有重要参考价值。本文分析总结了北京奥运会交通组织规划及交通组织运行经验启示。     

欧盟《可持续和智能交通战略》要点及启示

欧盟委员会基于2011年版交通白皮书目标任务进展有限,以及交通运输业可持续发展压力加大、新技术带来机遇挑战和新冠肺炎大流行要求交通具有更大韧性等新形势,在2020年12月发布《可持续和智能交通战略》,将发展可持续、智慧和韧性交通等三方面作为战略要点,重点推动交通向零排放时代转型,实现交通无缝、安全和有效链接,促进交通一体化、公平和无障碍发展。借鉴欧盟经验,为支撑我国交通强国建设和实现交通减碳目标,建议我国应深化重要交通政策文件评估管理,科学审慎制定交通运输减碳计划和政策体系,推动新技术率先在交通运输业探索应用,全方位提高交通运输韧性保障水平。     

交通事故预警系统构建

针对交通安全现状及国内外交通预警发展现状的分析,阐明建立交通事故预警系统的必要性。分析了基于人、车、路、环境四要素的道路交通事故的成因,根据交通事故预警系统设计原则和建立预警系统的目的,采用相关理论,选用合适的交通信息采集技术,建立了交通事故预警系统。该系统包括驾驶员预警子系统、车辆防撞预警子系统、车辆状况预警子系统、道路安全预警子系统和交通气象预警子系统。     

道路交通事故发生机理与实例分析

交通事故发生机理是认识道路交通事故发生过程、交通事故预防和改善交通安全的基础。文章以道路交通系统为研究对象,分析道路交通事故的形成过程,将交通事故发生机理分为驾驶行为差错类事故发生机理、外部因素突变类事故发生机理、综合性事故发生机理三类,并在此基础上绘制了道路交通事故发生机理图,同时结合国道109线兰州八盘村路段进行了实例分析。     

桂林市老城区分流交通保护圈规划设计

文章基于桂林市老城区交通现状,分析了老城区交通存在的主要问题,提出了桂林市老城区分流交通保护圈规划的总体思路,并根据这一思路设计出具体的老城区分流交通保护圈规划方案,为桂林市老城区交通系统规划提供决策依据。     

A real-time traffic signal control system: architecture, algorithms, and analysis

The paper discusses a real-time traffic-adaptive signal control system referred to as RHODES. The system takes as input detector data for real-time measurement of traffic flow, and “optimally” controls the flow through the network. The system utilizes a control architecture that (1) decomposes the traffic control problem into several subproblems that are interconnected in an hierarchical fashion, (2) predicts traffic flows at appropriate resolution levels (individual vehicles and platoons) to enable pro-active control, (3) allows various optimization modules for solving the hierarchical subproblems, and (4) utilizes a data structure and computer/communication approaches that allow for fast solution of the subproblems, so that each decision can be downloaded in the field appropriately within the given rolling time horizon of the corresponding subproblem. The RHODES architecture, algorithms, and its analysis are presented. Laboratory test results, based on implementation of RHODES on simulation models of actual scenarios, illustrate the effectiveness of the system.     

Adapt-Traf: An adaptive multiagent road traffic management system based on hybrid ant-hierarchical fuzzy model

Usually, road networks are characterized by their great dynamics including different entities in interactions. This leads to more complex road traffic management. This paper proposes an adaptive multiagent system based on the ant colony behavior and the hierarchical fuzzy model. This system allows adjusting efficiently the road traffic according to the real-time changes in road networks by the integration of an adaptive vehicle route guidance system. The proposed system is implemented and simulated under a multiagent platform in order to discuss the improvement of the global road traffic quality in terms of time, fluidity and adaptivity.     

Efficient multiple model particle filtering for joint traffic state estimation and incident detection

This article proposes an efficient multiple model particle filter (EMMPF) to solve the problems of traffic state estimation and incident detection, which requires significantly less computation time compared to existing multiple model nonlinear filters. To incorporate the on ramps and off ramps on the highway, junction solvers for a traffic flow model with incident dynamics are developed. The effectiveness of the proposed EMMPF is assessed using a benchmark hybrid state estimation problem, and using synthetic traffic data generated by a micro-simulation software. Then, the traffic estimation framework is implemented using field data collected on Interstate 880 in California. The results show the EMMPF is capable of estimating the traffic state and detecting incidents and requires an order of magnitude less computation time compared to existing algorithms, especially when the hybrid system has a large number of rare models.     

Dynamic charging-while-driving systems for freight delivery services with electric vehicles: Traffic and energy modelling

This paper presents a research on traffic modelling developed for assessing traffic and energy performance of electric systems installed along roads for dynamic charging-while-driving (CWD) of fully electric vehicles (FEVs).The logic adopted by the developed traffic model is derived from a particular simulation scenario of electric charging: a freight distribution service operated using medium-sized vans. In this case, the CWD service is used to recover the state of charge of the FEV batteries to shortly start with further activities after arrival at the depot.The CWD system is assumed to be implemented in a multilane ring road with several intermediate on-ramp entrances, where the slowest lane is reserved for the dynamic charging of authorized electric vehicles. A specific traffic model is developed and implemented based on a mesoscopic approach, where energy requirements and charging opportunities affect driving and traffic behaviours. Overtaking manoeuvres as well as new entries in the CWD lane of vehicles that need to charge are modelled according to a cooperative driving system, which manages adequate time gaps between consecutive vehicles. Finally, a speed control strategy is simulated at a defined node to create an empty time-space slot in the CWD lane, by delaying the arriving vehicles. This simulated control, implemented to allow maintenance operations for CWD that may require clearing a charging zone for a short time slot, could also be applied to facilitate on-ramp merging manoeuvres.     

福州市交通安全与智能交通系统探讨

智能交通系统是一个高科技集成系统,它综合运用各种高新技术于整个交通管理系统之中,可以系统、全面、高效地提高交通运输的安全性.文章阐述了智能交通系统在交通安全中的作用及在福州市的应用情况,指出了福州市发展智能交通的方向,以提高福州市的交通安全管理水平.     

“互联网+”交通信号辅助优化机制探索

为优化城市道路交通信号控制方法,本文结合交通信号控制系统建设发展现状,分析当前各大城市交通信号控制系统普遍存在的问题,立足于互联网环境下的浮动车数据,提出基于互联网平台大数据的交通信号控制辅助优化机制。研究发现可利用互联网路口拥堵报警数据及时有效发现问题路口,利用路段拥堵指数及路口交通流参数变化趋势辅助评估配时方案的优化效果,并通过成都市应用实例证明该机制适用于当前交通控制场景需求,可有效辅助交通信号优化工作,是传统交通模式向真正智能交通模式过渡的阶梯。     

Link-based day-to-day network traffic dynamics and equilibria

A general dynamical system model with link-based variables is formulated to characterize the processes of achieving equilibria from a non-equilibrium state in traffic networks. Several desirable properties of the dynamical system model are established, including the equivalence between its stationary state and user equilibrium, the invariance of its evolutionary trajectories, and the uniqueness and stability of its stationary points. Moreover, it is shown that not only a link-based version of two existing day-to-day traffic dynamics models but also two existing link-based dynamical system models of traffic flow are the special cases of the proposed model. The stabilities of stationary states of these special cases are also analyzed and discussed. In addition, an extension is made to the case with elastic demand. The study is helpful for better understanding the day-to-day adjustment mechanism of traffic flows in networks.