基于广义费用的城市轨道交通客流分配

为了更加客观全面地反映城市轨道交通出行者决策行为，提升城市轨道交通客流预测准确性，缓解线路运营面临的高峰时段客流拥挤现象，从出行广义费用角度出发，开展城市轨道交通客流分配研究。综合考虑票价、出行时间、舒适度、准时性等因素，构建了城市轨道交通乘客出行广义费用计算模型；以北京地铁5号线为例，将广义费用作为出行阻抗引入客流分配之中，构建了基于广义费用的随机用户平衡条件下的城市轨道交通客流分配模型，并提出了嵌套Logit模型的迭代加权法用以求解模型；基于分配模型及算法，对不同票价和列车容量条件下的城市轨道交通客流分配结果进行了对比分析。结果表明，基于广义费用的城市轨道交通客流分配模型能够实现对轨道交通流量的有效预测，可对各类缓解高峰时段拥挤措施的实施效果进行评估，辅助城市轨道交通领域相关决策。     

TOD理念对公交都市建设的启示

反思小汽车导向的城市发展模式20世纪80年代开始国内外城市规划、交通工程等领域的学者开始对以小汽车为导向的城市发展模式进行反思,发现这种交通发展模式下带来的城市问题不仅越来越多,而且后果越来越严重。交通拥挤愈发严重特大城市大部分地区高峰时段道路交通量接近饱和,有的城市中心区交通已接近半瘫痪,部分特大城市已经从上下班拥堵,扩展到不分时段、场合的拥堵。随着个人小汽车进入家庭,交通拥堵正在从特大城市迅     

伦敦城市交通理念与交通管理透视

本文对英国伦敦的交通理念进行了分析,总结和阐述了伦敦交通的特点,并重点介绍了伦敦拥挤收费的交通政策。     

拥挤收费:缓解我国道路交通拥堵的有效途径

随着经济的发展,交通拥挤已成为一个困扰世界各国大中城市的严重问题。本文从理论和现实两方面分析了道路拥挤收费在我国实施的必要性和可行性,并从我国城市交通实际出发,借鉴国外的经验,提出了以道路拥挤收费为主导的交通拥挤治理思路。     

城市交叉口交通拥挤最大排队长度估算模型

文章针对交通波模型应用于城市道路排队长度估算所存在的问题，评述了累计到达-离去模型应用的优势。通过对累计到达-离去模型的三种变形形式的分析比较，选用出其中的一种模型为基础模型进行改进，得到城市交叉口交通拥挤最大排队长度估算模型，并通过VISSIM仿真实验验证了这一改进模型的实用性。     

呼和浩特市交通拥挤收费必要性与可行性分析

文章基于拥挤收费理论基础,针对呼和浩特的市区交通拥挤问题,从呼和浩特市机动车增长迅速、人口分布不均衡、交通供给增加的潜力小和严重的拥堵现状等方面出发分析了拥挤收费的必要性,并从政策和经济潜力方面进行了可行性分析,同时给出了实行拥挤收费技术模式的相关建议。     

网络化运营模式下城市轨道交通客流分布特性

本文从网络化运营角度,以实际运营网络客流数据为基础,对城市轨道交通客流时间和空间分布特性进行了综合分析。时间分布上主要分析了日客流、周客流、月客流和年客流四个层面的客流特性,空间分布上主要采用了全网客流、高峰断面方向、进出站方向等指标来分析客流分布不均衡性。     

临沂市道路交通发展初探

通过对临沂城市道路交通拥挤状况的阐述，提出以可持续发展的观念分析解决城市道路交通中的问题。     

城市公交密集线路设站方式探讨

针对公交线路重复,站点密集,导致多车停靠产生交通拥挤的现象,对公交站点的设置形式进行研究,以平均排队长度作为评价指标,运用Vissim加以仿真,得到不同情形下适合的站点选型。     

"科技奥运"确保高水平交通服务

科学确定奥运交通需求 利用智能交通理论和技术手段,对奥运会期间社会交通和奥林匹克大家庭成员及大量志愿者、工作人员、观众交通运行建立模型,进行计算机模拟仿真;对组委会几千辆直接为贵宾、运动员、媒体等不同类型的客户群体服务的车辆组织和调度系统进行优化设计;对服务于观众的公交专用线路进行配置优化;对可能发生的问题和不利影响进行全面的风险评估.以此为基础,确定了奥运会期间包括要员贵宾、运动员、技术官员、赞助商、媒体在内的奥林匹克大家庭成员以及工作人员、志愿者、观众等不同交通服务客户群体的交通需求和服务标准,奥运交通服务任务、内容和指南,在此基础上制定奥运交通运行和实施计划.     

Empirical assessment of urban traffic congestion

This paper presents an empirical assessment of urban traffic congestion in Central London, UK. Compared with freeways or motorways, urban networks are relatively less studied because of its complexity and availability of required traffic data. This paper introduces the use of automatic number plate recognition technology to analyze the characteristic of urban traffic congestion in Central London. We also present the use of linear regression to diagnose the observed congestion and attribute them to different causes. In particular, we distinguish the observed congestion into two main components: one due to recurrent factors and the other due to nonrecurrent factors. The methodologies are illustrated through a case study of Central London Area. It is found that about 15% of the observed congestion in the region is due to nonrecurrent factors such as accidents, roadwork, special events, and strikes. Given the significance of London, the study will be valuable for transport policy evaluation and appraisal in other global cities. Copyright © 2013 John Wiley & Sons, Ltd.     

Characterization and comparison of traffic flow on reversible roadways

Reversible traffic operations have become an increasingly popular strategy for mitigating traffic congestion associated with the directionally unbalanced traffic flows that are a routine part of peak commute periods, planned special events, and emergency evacuations. It is interesting that despite its widespread and long‐term use, relatively little is known about the operational characteristics of this form of operation. For example, the capacity of a reversed lane has been estimated by some to be equal to that of a normal lane while others have theorized it to be half of this value. Without accurate estimates of reversible lane performance it is not possible to confidently gauge the benefits of reversible roadways or model them using traffic simulation. This paper presents the results of a study to measure and evaluate the speed and flow characteristics of reverse‐flow traffic streams by comparing them under various operating conditions and locations. It was found that, contrary to some opinions, the flow characteristics of reverse‐flowing lanes were generally similar to normally flowing lanes under a variety of traffic volume, time‐of‐day, location, and type‐of‐use conditions. The study also revealed that drivers will readily use reversible lanes without diminished operating speeds, particularly as volumes increase. Copyright © 2010 John Wiley & Sons, Ltd.     

Traffic control in over‐saturated conditions

This paper presents a review of traffic control as applied to congested or over‐saturated conditions. The paper begins with an introduction to traffic control in general, it then goes on to describe types of congestion, objectives for congestion control and some approaches to congestion control. Although the paper is mainly concerned with traffic signal control, other measures such as road pricing are described briefly.

More and more, traffic engineers have realized that existing traffic signals fail to perform satisfactorily under prolonged congestion or over‐saturated conditions. The paper identifies a number of theoretical studies which attempt to deal with such problems. It then describes the following traffic control systems, OPAC, PRODYN, SAGA, SCATS, SCOOT, STAUKO and UTOPIA, some more developed than others, and discusses their ability to deal with congestion. The paper presents the author's conclusions and recommendations for future research in the development of over‐saturation strategies.     

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.     

A dynamic evacuation model for pedestrian–vehicle mixed-flow networks

In urban emergency evacuation, a potentially large number of evacuees may depend either on transit or other modes, or need to walk a long distance, to access their passenger cars. In the process of approaching the designated pick-up points or parking areas for evacuation, the massive number of pedestrians may cause tremendous burden to vehicles in the roadway network. Responsible agencies often need to contend with congestion incurred by massive vehicles emanating from parking garages, evacuation buses generated from bus stops, and the conflicts between evacuees and vehicles at intersections. Hence, an effective plan for such evacuation needs to concurrently address both the multi-modal traffic route assignment and the optimization of network signal controls for mixed traffic flows. This paper presents an integrated model to produce the optimal distribution of vehicle and pedestrian flows, and the responsive network signal plan for massive mixed pedestrian–vehicle flows within the evacuation zone. The proposed model features its effectiveness in accounting for multiple types of evacuation vehicles, the interdependent relations between pedestrian and vehicle flows via some conversion locations, and the inevitable conflicts between intersection turning vehicle and pedestrian flows. An illustrating example concerning an evacuation around the M&T stadium area has been presented, and the results indicate the promising properties of our proposed model, especially on reflecting the complex interactions between vehicle and pedestrian flows and the favorable use of high-occupancy vehicles for evacuation operations.     

Analyzing the impact of a planned transit-oriented development on mode share and traffic conditions

ABSTRACT

Transit-oriented development (TOD) is a popular planning strategy used to maximize accessibility to transit for various trip purposes. The quantitative effects of TOD on travel mode shift and traffic congestion have not been extensively tested in the current literature. This paper utilizes a seemingly unrelated regressions (SUR) mode share model and a mesoscopic dynamic traffic assignment (DTA) model to analyze the impact of a planned TOD in Maryland. The proposed model aims at improving the understanding of the quantitative impacts of such a TOD on mode share and traffic congestion. The main result of the mode share model indicates that the increase in transit ridership for a transit accessible shopping center is not that significant. Local traffic conditions will deteriorate due to a lack of investment in road infrastructure planned for the TOD area. The proposed method could be a valuable tool for other indicative land development or transportation policy analyses.     

Bottleneck congestion and distribution of work start times: The economics of staggered work hours revisited

Since the seminal work of Henderson (Henderson, J.V., 1981. The economics of staggered work hours. Journal of Urban Economics 9 (3), 349–364), a number of studies have examined the effect of staggered work hours by analyzing models of work start time choice that consider the trade-off between negative congestion externalities and positive production externalities. However, these studies employed flow congestion models to describe traffic congestion. This study develops a model of work start time choice with bottleneck congestion and discloses the intrinsic properties of the model. To this end, this study extends Henderson’s model to incorporate bottleneck congestion. By utilizing the properties of a potential game, we characterize equilibrium and optimal distributions of work start times. We also show that Pigouvian tax/subsidy policies generally yield multiple equilibria and that the first-best optimum must be a stable equilibrium under Pigouvian policies, whereas the second-best optimum in which policymakers cannot eliminate queuing congestion can be unstable.     

Including congestion effects in urban road traffic CO2 emissions modelling: Do Local Government Authorities have the right options?

Tailpipe emissions from vehicles on urban road networks have damaging impacts, with the problem exacerbated by the common occurrence of congestion. This article focuses on carbon dioxide because it is the largest constituent of road traffic greenhouse gas emissions. Local Government Authorities (LGAs) are typically responsible for facilitating mitigation of these emissions, and critical to this task is the ability to assess the impact of transport interventions on road traffic emissions for a whole network.This article presents a contemporary review of literature concerning road traffic data and its use by LGAs in emissions models (EMs). Emphasis on the practicalities of using data readily available to LGAs to estimate network level emissions and inform effective policy is a relatively new research area, and this article summarises achievements so far. Results of the literature review indicate that readily available data are aggregated at traffic level rather than disaggregated at individual vehicle level. Hence, a hypothesis is put forward that optimal EM complexity is one using traffic variables as inputs, allowing LGAs to capture the influence of congestion whilst avoiding the complexity of detailed EMs that estimate emissions at vehicle level.Existing methodologies for estimating network emissions based on traffic variables typically have limitations. Conclusions are that LGAs do not necessarily have the right options, and that more research in this domain is required, both to quantify accuracy and to further develop EMs that explicitly include congestion, whilst remaining within LGA resource constraints.     

Time-dependent congestion pricing system for large networks: Integrating departure time choice,dynamic traffic assignment and regional travel surveys in the Greater Toronto Area

Congestion pricing is one of the widely contemplated methods to manage traffic congestion. The purpose of congestion pricing is to manage traffic demand generation and supply allocation by charging fees (i.e., tolling) for the use of certain roads in order to distribute traffic demand more evenly over time and space. This study presents a framework for large-scale variable congestion pricing policy determination and evaluation. The proposed framework integrates departure time choice and route choice models within a regional dynamic traffic assignment (DTA) simulation environment. The framework addresses the impact of tolling on: (1) road traffic congestion (supply side), and (2) travelers’ choice dimensions including departure time and route choices (demand side). The framework is applied to a simulation-based case study of tolling a major freeway in Toronto while capturing the regional effects across the Greater Toronto Area (GTA). The models are developed and calibrated using regional household travel survey data that reflect the heterogeneity of travelers’ attributes. The DTA model is calibrated using actual traffic counts from the Ontario Ministry of Transportation and the City of Toronto. The case study examined two tolling scenarios: flat and variable tolling. The results indicate that: (1) more benefits are attained from variable pricing, that mirrors temporal congestion patterns, due to departure time rescheduling as opposed to predominantly re-routing only in the case of flat tolling, (2) widespread spatial and temporal re-distributions of traffic demand are observed across the regional network in response to tolling a significant, yet relatively short, expressway serving Downtown Toronto, and (3) flat tolling causes major and counterproductive rerouting patterns during peak hours, which was observed to block access to the tolled facility itself.     

Transportation planning and institutional rigidities in Surat,India

This paper while reviewing the prevalent traffic and transportation problems in a metropolitan city of India namely Surat, identifies certain institutional rigidities which mar prospects of planned improvements. The old city of Surat known as the Walled City is the center of chronic traffic congestion which is due to a variety of causes. Owing to the past neglect and the on-going developments, the Walled City is beset with numerous traffic and transportation as well as other problems. Based on an indepth analyses of field data, a series of short and long term remedial measures were worked out to cope with the immediate and the future travel demands. Of the proposals made, the traffic management scheme is designed to optimize the use of available infrastructural facilities with a thrust towards bus transportation. However, the success of these measures depends on the relaxation of the outdated practices which could stifle the implementation of the suggested solutions.