Incorporating spatial equity into interurban road network design

Methods for the road network design problem, typically, are based on optimization of the network efficiency measures (e.g. network-wide travel time) under a predefined budget. In these approaches, equity issues are not taken into account and, consequently, most of the road improvements are planned next to large cities. Thus, disparities between large and small cities increase, which does not conform to sustainable development objectives. In this paper, to overcome concerns associated with traditional methods, equity is incorporated into the interurban road network design problem. To this end, accessibility concepts are employed. However, unlike previous studies, instead of maximizing the total accessibility, a new definition is proposed for inaccessibility, and total inaccessibility is minimized throughout the network. Using this new definition not only is more compatible with the equity issue, but also helps to eliminate the nonlinearity of the problem. Average travel time to neighboring opportunities is utilized to propose this definition for inaccessibility, which captures the reality more effectively. With the aim of this definition, equity is incorporated into the road network design problem implicitly. This is another improvement over previous methods, where a new term in the objective function or a new constraint is added to include the equity. The proposed model is formulated as a mixed integer linear programming (MILP) problem, where the objective is to minimize the aggregate inaccessibility over all the population centers in the network. To illustrate the application of the model, the Northwest region of the United States is used as the case study. The respective exact solution of the example is found using a commercial solver (CPLEX). This new solution is also compared with the solutions from the traditional methods.     

沪通铁路建设背景下的南通区位形势及交通行业影响预测

沪通铁路建设的帷幕在南通提出加快沿江沿海开发和建设长三角北翼经济中心的背景下正式拉开。沪通铁路工程将对南通地方交通格局及交通运输行业形成重要影响。文章将首先对南通地方交通体系的历史和现状作简要陈述,在此基础上,围绕沪通铁路的建设对完善南通地方交通体系格局的作用展开分析,然后就该工程对南通地方交通行业的影响作综合分析和预测。     

高速磁浮列车技术及其在我国客运交通中的战略地位

高速磁浮列车是当前唯一能达到５００公里／时运营速度的地面交通工具．技术已经成熟．正进入实用运营线建造阶段，将在２１世纪高速客运中发挥重大作用。本文简要介绍了高速磁浮列车技术的发展情况与特点，分析了其在客运交通系统中的地位。从我国国情出发，本文论述了其在我国未来客运交通中的战略地位，并对我国当前发展磁浮列车技术提出了一些建议。     

AN INVESTIGATION OF THE VALUE OF CROSS‐DOCKING FOR SUPPLY CHAIN MANAGEMENT

Cross‐docking is the practice of transferring materials from an incoming shipment directly to an outgoing shipment without storing them at the transfer point. This essentially eliminates the inventory‐holding function of a warehouse and can reduce supply chain costs. We investigate the value of one type of cross‐docking in a variety of supply chain environments.     

A survey on pickup and delivery problems

This paper is the first part of a comprehensive survey on pickup and delivery problems. Basically, two problem classes can be distinguished. The first class, discussed in this paper, deals with the transportation of goods from the depot to linehaul customers and from backhaul customers to the depot. This class is denoted as Vehicle Routing Problems with Backhauls (VRPB). Four subtypes can be considered, namely the Vehicle Routing Problem with Clustered Backhauls (VRPCB – all linehauls before backhauls), the Vehicle Routing Problem with Mixed linehauls and Backhauls (VRPMB – any sequence of linehauls and backhauls permitted), the Vehicle Routing Problem with Divisible Delivery and Pickup (VRPDDP – customers demanding delivery and pickup service can be visited twice), and the Vehicle Routing Problem with Simultaneous Delivery and Pickup (VRPSDP – customers demanding both services have to be visited exactly once). The second class, dealt with in the second part of this survey, refers to all those problems where goods are transported between pickup and delivery locations. These are the Pickup and Delivery Vehicle Routing Problem (PDVRP – unpaired pickup and delivery points), the classical Pickup and Delivery Problem (PDP – paired pickup and delivery points), and the Dial-A-Ride Problem (DARP – passenger transportation between paired pickup and delivery points and user inconvenience taken into consideration). Single as well as multi vehicle versions of the mathematical problem formulations are given for all four VRPB types, the corresponding exact, heuristic, and metaheuristic solution methods are discussed.      

Distributional effects of environmental taxes on transportation: evidence from Engel curves in the United States

Indirect taxes on transportation activities that pollute can correct externalities and close the gaps between private and social costs. However, policy makers often find such Pigou taxes difficult to implement because of political resistance due to possibly adverse affects on equity. For this reason it is important to assess the distributional aspects of environmental levies. This article estimates properties of the demand for transportation in parametric and non-parametric analyses of Consumer Expenditure Surveys for the United States and finds patterns in the resulting set of Engel curves. Private transportation using air flights and new cars has Engel elasticity above unity while public transportation via mass transit has Engel elasticity below unity. The findings can be interpreted in an important way since they show that a differentiated scheme of environmental taxes on transportation may function progressively. A Pigou scheme with larger taxes on modes of transportation that pollute more appears to coincide with larger levies on luxury modes preferred by richer households.     

政府绩效审计“阶梯型”评价模式的构建与应用——以BRT公共交通投资项目为例

构建一套政府公共交通投资项目绩效审计评价模式是提高政府公共交通投资项目绩效审计效率和审计质量的关键,然而目前业界尚未对此形成统一认识。论文基于平衡计分卡理论从资源配置、职能行使、潜力发挥和贡献效益四个维度,构建了“阶梯形”政府公共交通投资项目绩效审计评价模式,并通过模糊评价对某市BRT项目调研数据对该模式进行了验证。     

基于物流视角的北宋粮食纲运分析

基于物流系统要素理论,从一般要素、功能要素、支持要素和物质基础要素四个方面分析了北宋粮食纲运系统,从纲制编排与纲运限程、纲运管押与催检、行运秩序与安全保障三个方面描述了北宋粮食纲运的管理过程,纲运过程存在着诸如纲物丢失、损坏、延期运抵等问题,造成这些问题的主要原因是在押纲、催检和起卸三个环节上的官吏腐败。     

厦门经济特区扩容背景下的城市交通战略规划探讨

在国务院批准厦门经济特区扩大到全市的背景下,结合分析厦门城市近年来交通现状的基础上,紧紧围绕“全城厦门的理念统筹城乡交通战略规划,积极推进岛内岛外交通一体化建设,构筑以公共交通为主体的可持续城市交通发展模式.