多种交通方式下的城市空间分配

从集计角度分析了运行多种交通方式的城市交通系统。利用目前已受关注的宏观基本图（简称MFD）,描述城市交通的整体特性。以旧金山某区为例,使用现有数据,通过仿真论证如何应用MFD监管真实交通网络。然后讨论了同一路网中不同交通方式间如何相互作用,以及如何将这些作用纳入包含多种交通方式路网的MFD。研究得到的两个主要结论是：1）证实了已有研究猜想——对市区拥挤区域限行,可提高包括被限行者在肉的所有出行者的机动性;2）公交方式提供专用道路空间可提高所有交通方式的可达性。     

基于AFC系统的苏州市轨道交通网络化客流特征分析及启示

从运营轨道线网客流中找寻规律,可以有效指导城市科学合理地预测轨道交通客流。本文根据目前苏州市AFC系统运营数据积累,从网络、线路、车站三个层面探讨苏州市轨道交通客流特征,分析目前线网客流特征,为后续预测模型的参数选择提供参考和依据,并且针对轨道交通规划设计及运营提出相关工作建议。     

重庆市轨道交通网络化新形势下的地面常规公交转型发展对策研究

近年来,随着轨道交通的大规模建设和交通出行方式的多样化,给地面常规公交带来了前所未有的挑战和压力,常规公交客流呈现下降趋势已经成为普遍现象.本文主要以重庆为例,基于轨道交通网络化发展,探究在轨道网发展过程中常规公交面临的困境,提出在新常态下常规公交的发展定位和发展策略,构建"以轨道为骨干,常规公交为基础"的公共交通一体化网络,从而实现地面公交服务效率和品质的全面提升,使其最终实现成功转型发展.     

Environmental innovation and the role of stakeholder collaboration in West Coast port gateways

The paper explores the role of stakeholder collaboration in the adoption of innovations as part of the environmental and sustainability agenda of port gateways. We do this through a comparative assessment of the port of Vancouver, British Columbia, and the twin ports of Los Angeles and Long Beach, California. An inductive research approach is used to identify and assess the initiation and implementation process behind exemplary innovations. Innovation includes new technologies and processes for handling and moving cargo, mechanisms for planning and policy making, as well as financing, implementing, upgrading, managing and operating infrastructure systems. A relatively new arena for competition on the basis of innovation concerns environmental performance. The conceptual framework and empirical evidence suggest that while there may be intense demand for and supply of innovation in port gateways, the complex dynamics of the logistics chain are such that successful innovation requires conscious involvement and collaboration of stakeholders.     

Rail infrastructure,ITS and access charges

This paper presents an overview of the principles and technologies relating to railway infrastructure. Specifically this paper includes rail–wheel contact, inspection and maintenance of rail. Intelligent transport systems (ITS) and their applications for the purposes of the railway transport in Europe are discussed. The potential, levels of development, technological and operational characteristics of the European Railway Traffic Management System (ERTMS) are presented. Finally, a discussion on methodologies, principles and current practices for access charging in Europe is provided.     

Numerical prediction of the modal response of flexible cylinders in cross-flow with a current dependent form of damping

A quadratic eigenvalue problem (QEP) was posed in order to study the dynamics of flexible cylinders in cross-flow, simulating slender offshore structures such as risers, catenaries or tendons. The Euler–Bernoulli equation was used to model the structure assuming a fluid loading model, and yielding a quadratic eigenvalue problem that included a form of damping dependent not only on the structural damping itself, but also on the free stream velocity and the fluid force coefficients. We solved the QEP using the finite element method. We also derived a simplified analytical solution in this work for comparison with the QEP, however this solution does not consider changes in tension along the length of the cylinder as the QEP does. In our study, the QEP solutions were first validated against the simplified analytical solution, and also against a well-known experimental dataset obtained in 2003, in which a flexible circular cylinder model was used to model the dynamics of a riser undergoing multi-mode vortex-induced vibrations.     

EFD and CFD for KCS heaving and pitching in regular head waves

The KCS container ship was investigated in calm water and regular head seas by means of EFD and CFD. The experimental study was conducted in FORCE Technology’s towing tank in Denmark, and the CFD study was conducted using the URANS codes CFDSHIP-IOWA and Star-CCM+ plus the potential theory code AEGIR. Three speeds were covered and the wave conditions were chosen in order to study the ship’s response in waves under resonance and maximum exciting conditions. In the experiment, the heave and pitch motions and the resistance were measured together with wave elevation of the incoming wave. The model test was designed and conducted in order to enable UA assessment of the measured data. The results show that the ship responds strongly when the resonance and maximum exciting conditions are met. With respect to experimental uncertainty, the level for calm water is comparable to PMM uncertainties for maneuvering testing while the level is higher in waves. Concerning the CFD results, the computation shows a very complex and time-varying flow pattern. For the integral quantities, a comparison between EFD and CFD shows that the computed motions and resistance in calm water is in fair agreement with the measurement. In waves, the motions are still in fair agreement with measured data, but larger differences are observed for the resistance. The mean resistance is reasonable, but the first order amplitude of the resistance time history is underpredicted by CFD. Finally, it seems that the URANS codes are in closer agreement with the measurements compared to the potential theory.     

Are Longer and Heavier Vehicles (LHVs) Beneficial for Society? A Cost Benefit Analysis to Evaluate their Potential Implementation in Spain

Abstract

In this paper we carry out a thorough review of the current research related to the benefits and costs arising from the implementation of longer and heavier vehicles (LHVs). From this review we concluded that despite the many studies available, little has been said about the sensitivity of the benefits and costs to the ultimate performance of the key variables related to the evolution of the economy, road transport performance, safety, and so on. In order to fill this gap, we have designed a sensitivity approach based on a cost benefit analysis tool to determine which variables demonstrate the greatest influence on the benefits and costs stemming from the implementation of LHVs. In order to test the methodology, we have used it in an analysis of the Spanish trunk network. The results show that the benefits of LHVs for society are significant. Even in the least favorable scenario, the economic benefits are greater than €3500 million over 15 years, and the environment enhanced as well, for CO₂ emissions are reduced by 2 Million tonnes. Overall we noted how the results are not very sensitive to the evolution of key variables in determining the final outcome. However, we found that the variables that have the greatest affect on the final benefit, such as traffic growth and social discount rate, depend basically on the performance of the overall economy. Moreover, the private cost for haulers seems to be more important in determining the final benefit than externality costs.     

Workplace travel plans: can they be evaluated effectively by experts?

Employers are regularly involved in transport planning and characteristic workplace-oriented tools include: (1) travel plans for building projects, (2) mandatory travel plans, (3) subsidies to employers with an advanced travel plan and (4) best travel plan awards. In all cases, experts judge the level of car use. We argue that decision-makers might benefit from a multiple regression-based benchmark modelling tool that estimates the expected share of the car. In this paper, we estimate the share of car users in the commuting modal split at workplaces. However, since the amount of information available to experts differs, we gradually add information to the model to measure the impact of data availability. Without historic data on modal split, the current share can only be predicted moderately well, i.e. within a 20% range. Besides adding the past, results improve by using homogenous and regional subsamples. Nevertheless, quantitative analyses do not make expert knowledge obsolete.     

A Modeling Framework for Bus Rapid Transit Operations Evaluation and Service Planning

Abstract

In this paper, we present a dynamic traffic assignment-simulation modeling framework (DYNASMART-P) to support the evaluation and planning of Bus Rapid Transit (BRT) services in urban transportation networks. The model represents the different characteristics associated with BRT operations such as: exclusive right-of-way lanes, limited-stop service, signal prioritization at congested intersections, and enhanced bus stops to reduce passenger boarding times. A set of simulation experiments is conducted using the model to study the impact of introducing a hypothetical BRT service in the Knoxville area in the State of Tennessee. In these experiments, the different operational characteristics of BRT are evaluated in terms of potential impact on transit ridership and on the interacting auto traffic. The results illustrate the advantages of BRT for increasing transit ridership and improving overall system performance.