A new fuzzy approach to estimate the O–D matrix from link volumes

Abstract

Estimation of the origin–destination (O–D) trip demand matrix plays a key role in travel analysis and transportation planning and operations. Many researchers have developed different O–D matrix estimation methods using traffic counts, which allow simple data collection as opposed to the costly traditional direct estimation methods based on home and roadside interviews.

In this paper, we present a new fuzzy model to estimate the O–D matrix from traffic counts. Since link data only represent a snapshot situation, resulting in inconsistency of data and poor quality of the estimated O–Ds, the proposed method considers the link data as a fuzzy number that varies within a certain bandwidth. Shafahi and Ramezani's fuzzy assignment method is improved upon and used to assign the estimated O–D matrix, which causes the assigned volumes to be fuzzy numbers similar to what is proposed for observed link counts. The shortest path algorithm of the proposed method is similar to the Floyd–Warshall algorithm, and we call it the Fuzzy Floyd–Warshall Algorithm. A new fuzzy comparing index is proposed by improving the fuzzy comparison method developed by Dubois and Prade to estimate and compare the distance between the assigned and observed link volumes. The O–D estimation model is formulated as a convex minimization problem based on the proposed fuzzy index to minimize the fuzzy distance between the observed and assigned link volumes. A gradient-based method is used to solve the problem. To ensure the original O–D matrix does not change more than necessary during the iterations, a fuzzy rule-based approach is proposed to control the matrix changes.     

漠河的那山,那人,那路

漠河北极村是中国最北部的一个边陲小村,它的最大特点就是,随意一个地方,都可以说是中国最北端的:中国最北之家、最北的邮局、最北的小学、最北的乡政府……甚至还有最北的厕所。中国最北之家据说是经专家通过经纬度测定验证最北的一户人家,是北极村的地标性建筑。来这里的人,临走前都不忘在中国最北端的邮局里买张明信片,盖上最北端的邮戳,留作纪念。     

继续深化改革,统筹规划,加快交通运输发展

<正> 1995年是我国第八个五年计划的最后的一年,是制定“九五”计划及2010年发展规划、实现90年代我国第二步发展战略目标承前启后的重要一年。为此,党中央召开了经济工作会议,提出了1995年经济工作总的指导思想和主要任务:继续深化改革,扩大开放,保持国民经济持续、快速、健康的发展。交通运输战线的广大干部和职工认真学习贯彻党中央经济工作的指导方针,振奋精神,再接再励,在新的一年里为加快交通运输的发展作出新的贡献。     

认清形势,集中力量,加快交通基础设施建设

<正> 一、“八五”成就与问题 交通运输是我国国民经济和社会发展以及国防现代化建设的重要基础设施。“八五”是我国交通运输发展最快、经验最多的时期。经过“八五”时期的建设和发展,我国综合交通运输网络建设有了长足的进步。到“八五”期末,全国铁路营业里程由5万公里增加到6万公里,新建和改建公路9.2万公里,公路通车里程达到     

车展,车展,还缺些啥?

轰轰烈烈的车展季节又来了,而且很快就要过去。参与其中,置身其中,热热闹闹的人来人往,可是一旦离开现场,新闻同行间彼此互相聊起来,却又不记得车展到底看到了些什么,感受了什么,车展,难道真的就是一个形式、一个过场?前几年,谈起车展,所有厂商都兴致盎然,大规模的来,大规模的展示,大规模的去,而从2009年开始,车展逐渐沦     

未来,将来

正新时期对交通运输所提出的,是升级了的更高层次的需求;对交通人所提出的,是更专业化、更精细化、更具人文关怀的要求。积极推进供给侧结构性改革,要求全体交通人在新的一年大力推进交通基础设施"补齐短板"、物流业"降本增效"和客运服务"提质升级"。科幻电影《我,机器人》里,2035年令人眼花缭乱的未来城市蓝图中,新鲜而炫目的交通方式最让人难以忘怀。这并不仅仅是空想,很显然,伴随着资源的日渐枯竭以及环境污染的日益严重,寻求新的交通运输发展模式业已成为了迫     

A network‐based model for estimating the market share of a new high‐speed rail system

This paper presents a novel application of static traffic assignment methods, but with a variable time value, for estimating the market share of high‐speed rail (HSR) in the northwest–southeast (NW–SE) corridor of Korea currently served by air, conventional rail and highway modes. The proposed model employs a time–space network structure to capture the interrelations among competing transportation modes, and to reflect their supply‐ and demand‐side constraints as well as interactions through properly formulated link‐node structures. The embedded cost function for each network link offers the flexibility for incorporating all associated factors, such as travel time and fare, in the model computation, and enables the use of a distribution rather than a constant to represent the time–value variation among all transportation mode users. To capture the value‐of‐time (VOT) of tripmakers along the target corridor realistically, this study has developed a calibration method with aggregate demand information and key system performance data from the NW–SE corridor.     

Do new sources of traffic data make the application of Chaos Theory to traffic management a realistic possibility?

Current signal systems for managing road traffic in many urban areas around the world lack a coordinated approach to detecting the spatial and temporal evolution of congestion across control regions within city networks. This severely inhibits these systems’ ability to detect reliably, on a strategic level, the onset of congestion and implement effective preventative action. As traffic is a time-dependent and non-linear system, Chaos Theory is a prime candidate for application to Urban Traffic Control (UTC) to improve congestion and pollution management. Previous applications have been restricted to relatively uncomplicated motorway and inter-urban networks, arguably where the associated problems of congestion and vehicle emissions are less severe, due to a general unavailability of high-resolution temporal and spatial data that preserve the variability in short-term traffic patterns required for Chaos Theory to work to its full potential. This paper argues that this restriction can now be overcome due to the emergence of new sources of high-resolution data and large data storage capabilities. Consequently, this opens up the real possibility for a new generation of UTC systems that are better able to detect the dynamic states of traffic and therefore more effectively prevent the onset of traffic congestion in urban areas worldwide.     

Is a new applied transportation research field emerging?––A review of intermodal rail–truck freight transport literature

Intermodal freight transport has developed into a significant sector of the transport industry in its own right. This development has been followed by an increase in intermodal freight transportation research. We contend that a new transportation research application field is emerging; and that, while still in a pre-paradigmatic phase, it is now time to move on to a more mature independent research field. An independent research field can be justified because intermodal transport is a complex system that has characteristics which distinguishes it from other transport systems. We have reviewed 92 publications in order to identify the characteristics of the intermodal research community and scientific knowledge base. This paper will discuss aspects of this research, assessing the status quo and seeking directions for the future. To conclude, we will propose an intermodal research agenda which can direct the intermodal research field towards a period of “normal science”.     

三足,名稳

正一个多月前,国家发改委、交通运输部联合印发了《交通基础设施重大工程建设三年行动计划》。《计划》指出,"十三五"时期是交通基础设施重大工程建设的重要阶段,2016年至2018年拟重点推进铁路、公路、水路、机场、城市轨道交通项目303项,总投资4.7万亿。其中兴建和改扩建铁路两万公里,新建和改扩建公路六千公里,新建城市轨道交通线路2000公里。     

足迹所至,观念更新

<正>2011年3月15日,全国道路客运"海格智慧"科技助力行动如一粒火种,足迹所至,观念更新。2011年12月13日,燃遍全国的火种,在交通运输部机关落地。上午,镁光灯闪耀之下,交通运输部副部长冯正霖轻点鼠标左键,一辆营运客车的实时运行画面立即出现在厅内的显示屏上,车辆驾驶区、乘客区、上下车门的状况和前方路况让在场的200多人一目了然。短短9个月里,科技助力行动如飓风登岸,波澜壮阔,席卷车队,覆盖到全国19个省(市、自治