铁路客货列车分摊线路使用费比例的研究

客货列车均对线路造成损伤,但因运行速度、轴重和运量不同,则对线路损伤的程度不同,所承担线路使用费不同。从工务维修角度出发,以对线路使用费有决定性作用的钢轨抽换成本和轨道状态维修成本作为研究对象,建立客货列车线路使用费分摊比例的工程模型,对我国铁路进行大量现场调研,并用所建立的工程模型对现场调研数据进行处理,得到我国客运货运分摊线路使用费的比例。     

城乡结合部交通与枢纽规划研究

文章从城乡结合部和交通与枢纽的基本内涵出发,指出了城乡结合部存在的一些交通问题,同时针对城乡结合部已成为交通瓶颈,阻碍城市的对外经济联系和乡村经济发展等问题,提出了结合部交通与枢纽规划的优化设想。     

关于海事基础设施建设中的招投标管理

工程造价管理,贯穿于海事基础设施建设的全过程。而招投标阶段的造价控制,不仅能有效消除因项目前期深度、设计精度问题带来的造价不确定因素,也会为施工阶段的造价控制打下良好的基础,作者通过对影响招标投标阶段工程造价诸多因素的分析研究,提出有效控制工程造价的方法和建议,供广大同行参考。     

网络电话技术及应用

网络电话技术完全不同于传统的通信技术,是新的、纯粹的网络技术的应用,与IP电话也有本质的区别.概述当前的网络电话技术及相关的技术协议、标准,介绍3种网络电话应用软件特点及使用方法,并对网络电话的未来发展进行展望.     

铁路客运专线动车段检修信息系统需求分析与网络构建

分析了客运专线动车组检修作业信息流程,并从检修作业信息的建立、信息交换、信息处理、监控系统、网络系统5个方面,论述了检修信息系统的需求。     

Tradable emission permit system for urban motorists: The neo-classical standard model revisited

This article deals with the feasibility of a tradable emission permit system (TEPs) for urban motorists. The objective is to develop a new microeconomic theoretical model to reduce urban pollution. We suppose that the city's regulating authority sets up a tradable emission permit system based on the number of kilometres covered by private cars. By the use of a Constant Elasticity of Substitution (CES) function, we determine the equilibrium under an environmental constraint and analyse the effects of a TEPs on social welfare. The aim is to find the optimal quantity of permits leading to the desired environmental objective. The analytical and numerical results of the model show the instrument's feasibility and efficiency. An important variable in the model must be taken into account: the knowledge of environmental damage. This variable will clearly influence the tool's success.     

Assessment of policies and detection of unintended effects: Guiding principles for the consideration of methods and tools in policy-packaging

Single policies or entire policy packages are often assessed using different methods aiming at a quantification of effects as well as the detection of undesired outcomes. The knowledge of potential impacts is essential to take informed policy actions. Hence, there is a constant need for efficient assessment approaches to support policy decision-making. A broad range of such assessment methods is used in policymaking. Some of them are using quantitative data; others are characterized by qualitative information, observations or opinions. Practical experiences with transport policy prove that these methods all have their pros and cons, but none of them are able to detect the full range of effects. This leads to important questions this article deals with, such as what are the strengths and limitations of the different tools and methods for assessing impacts, and how should different approaches be integrated into the policymaking processes?We analyze the ability of assessment methods to detect different kinds of intended and unintended effects, and introduce the concepts of structurally open (mainly qualitative) and structurally closed (mainly quantitative) methods. It is argued that these concepts support making the pros and cons of the tools and methods more explicit and, thus, allow integrating the different tools and methods into the process of policy packaging. Based on a policy package example, we provide practical recommendations on how to integrate different assessment methods adequately and show that both quantitative and qualitative tools should be used in different phases of the process. The main recommendation is to alternate the application of assessment methods with structurally open methods used in the beginning and the end of the policymaking process and applying structurally closed methods in between.     

Transport network criticality metrics: a comparative analysis and a guideline for selection

ABSTRACT

Transport network criticality analysis aims at ranking transport infrastructure elements based on their contribution to the performance of the overall infrastructure network. Despite the wide variety of transport network criticality metrics, little guidance is available on selecting metrics that are fit for the specific purpose of a study. To address this gap, this study reviews, evaluates and compares seventeen criticality metrics. First, we conceptually evaluate these metrics in terms of the functionality of the transport system that the metrics try to represent (either maintaining connectivity, reducing travel cost, or improving accessibility), the underlying ethical principles (either utilitarianism or egalitarianism), and the spatial aggregation considered by the metrics (either network-wide or localised). Next, we empirically compare the metrics by calculating them for eight transport networks. We define the empirical similarity between two metrics as the degree to which they yield similar rankings of infrastructure elements. Pairs of metrics that have high empirical similarity highlight the same set of transport infrastructure elements as critical. We find that empirical similarity is partly dependent on the network’s topology. We also observe that metrics that are conceptually similar do not necessarily have high empirical similarity. Based on the insights from the conceptual and empirical comparison, we propose a five-step guideline for transport authorities and analysts to identify the set of criticality metrics to use which best aligns with the nature of their policy questions.