城市地铁车辆选型思考

以深圳市轨道交通为例,通过对深圳市地铁客流的分析,以及对A、B型车的建设成本与运营成本的比较,探讨城市轨道交通车辆选型的问题。最后得出结论：1）车辆选型应全线综合考虑,尽量选用建设及运营成本较经济的车型。针对局部区间运能不足的情况,应增强城市轨道交通线网布局,增强各运营线路的换乘节点数量,完善局部区域的城市综合交通体系,给市民的出行提供多种选择。2）车辆选型从节能方面应综合考虑整个运营期间的乘客满载率。3）因B型车车体的长度、宽度及线路曲线半经小于A型车,故从地铁站、区间、车辆段土建结构造价及工程拆迁成本,以及运营噪声和振动等方面考虑,如B型车能满足远期客流要求,选用B型车较A型车更能体现地铁绿色环保的价值。     

The distribution of crowding costs in public transport: New evidence from Paris

Whilst congestion in automobile traffic increases trip durations, this is often not the case in rail-based public transport where congestion rather leads to in-vehicle crowding, often neglected in empirical studies. Using original survey data from Paris, this article assesses the distribution of comfort costs of congestion in public transport. Estimating willingness to pay for less crowded trips at different levels of in-vehicle passenger density we cannot reject a simple linear relationship between crowding costs and density. We apply our results to the cost-benefit analysis of a recent Parisian public transport project.     

高聚物注浆技术处治高速公路病害的经济效益分析

高聚物注浆维修高速公路病害技术是公路养护维修技术领域的新成果，体现了非开挖、精细化的理念，具有施工快捷、根治病害等优点，与传统维修方式相比，体现了显著的经济效益和社会效益。以安新高速公路示范工程为例，从直接效益和间接效益两方面对高聚物注浆技术和常规开挖换填两种方案进行了分析评价，结果表明高聚物技术具有明显的经济效益，可节省费用10552．73万元，效益提高56．56％。     

基于动态规划模型的部队返程问题优化应用研究

简要介绍了动态规划的多阶段决策过程、最优性原理和最优性定理,并以某军区打靶部队返程运输为例,建立动态规划模型,优化运输计划,达到以尽可能小的代价完成部队返程运输保障的目的,为解决同类问题提供思路。     

浅议全球高油价背景下船舶降低燃油成本的对策

文章分析了船舶燃油管理及其消耗所存在的问题,并提出了降低船舶运营燃油成本的对策,以达到降低油耗、控制成本和节能减排的目的,对推动绿色航运具有一定的实践指导意义。     

The econometric estimation of airports’ cost function

The econometric estimation of cost functions has been proposed in the literature as a suitable approach in order to obtain estimations of marginal costs, efficiency levels and scale elasticities for transport industries. However, regarding the airport industry, no significant attention has been paid in developing an airport-specific estimation methodology rather than adapting the procedures applied to other industries. The lack of comparable airport data is one of the causes which could explain the scarcity of this literature in the past, as well as the use of very limited approaches to explain airport technology. This paper tries to overcome these limitations by developing an airport-specific methodology to estimate a multi-output long-run cost function using an unbalanced pooled database on 161 airports worldwide. The specification of hedonically-adjusted aircraft operations, domestic and international passengers, cargo and commercial revenues in the output vector, as well as the calculation of input prices are discussed. Both technical and allocative inefficiencies are specified in the model using a Stochastic Frontier method that has been estimated through Bayesian Inference and Markov Chain Monte Carlo methods.     

A set-covering model for a bidirectional multi-shift full truckload vehicle routing problem

This paper introduces a bidirectional multi-shift full truckload transportation problem with operation dependent service times. The problem is different from the previous container transport problems and the existing approaches for container transport problems and vehicle routing pickup and delivery are either not suitable or inefficient. In this paper, a set covering model is developed for the problem based on a novel route representation and a container-flow mapping. It was demonstrated that the model can be applied to solve real-life, medium sized instances of the container transport problem at a large international port. A lower bound of the problem is also obtained by relaxing the time window constraints to the nearest shifts and transforming the problem into a service network design problem. Implications and managerial insights of the results by the lower bound results are also provided.     

Generalized transport costs and index numbers: A geographical analysis of economic and infrastructure fundamentals

We rely on the economic theory approach to index numbers to improve the existing definitions and decompositions of variations in generalized transport costs (GTCs). As a value index, we decompose GTCs into price and quantity indices associated to economic—market—costs and infrastructure variables—distance and time within a network. The methodology allows the accurate identification of the sources of GTCs decline. We illustrate it for the case of road freight transportation in Spain between 1980 and 2007 and at a highly detailed geographical level. Average GTCs weighted by trade flows have decreased by 16.3%, with infrastructure driving that reduction. We find large territorial disparities in GTCs, but also significant geographical clusters where the market and network indices show spatial association.     

An advanced traveler general information system for Fresno,California

This study estimates the effects of an advanced traveler general information system (ATGIS), which includes fuel consumption and health-related emissions cost information on transportation network users’ travel choice behavior for recurrent congestion conditions. The effects are estimated using four different formulations based on four different behavioral assumptions. Incorporating stochastic features in link cost estimation rather than in route choice, we provide a novel modeling approach that enables us to use transportation planning models of major metropolitan areas without a need for major computationally-expensive changes in the existing models. We examined the effects of an ATGIS on the Fresno, CA, road network and found several interesting results. First, the ATGIS impact is closely related to pre-system (prior to the implementation of an ATGIS) perceived fuel and emissions costs. Total travel time in the city can be reduced by 17% (no pre-system perceived costs) to 1% (accurate pre-system perceived costs), and even increased by 1% (higher-than-actual pre-system perceived costs). Second, the addition of emissions costs, although negligible relative to fuel and time costs, can effectively reduce total system-wide travel time by up to 1% and fuel consumption by up to 0.6% during peak hours. Third, the ATGIS can reduce annual social costs by as much as $1053 million (high gas price, no pre-system perception) to $48 million (medium gas price, accurate pre-system perception), which are comparable to social cost savings by a congestion pricing (CP) scheme in the study area.     

Achieving environmental sustainability beyond technological improvements: Potential role of high-speed rail in the United States of America

In order to reduce energy use and cut emissions that contribute to climate change, countries need to radically reinvent their fossil-fuel intensive transportation systems. As a major consumer of energy and contributor to greenhouse gas (GHG) emissions, the U.S. transportation sector faces extraordinary challenges in the twenty-first century. Transportation in the U.S. depends heavily on fossil-fuel dependent cars and planes to the near exclusion of more energy-efficient electric trains. In order to address this concern, some policy makers refer to “technological optimism” which seeks no systemic change but instead focuses on employing technology to reduce the energy demand and environmental impact of the status quo. On the other hand, some researchers suggest a systematic paradigm shift away from cars and planes to intermodal systems that improve the sustainability of the system as a whole. High-speed rail (HSR) is arguably such an investment that can further this shift and help to achieve a more diversified and balanced transportation system. In this respect, by largely examining the role of the U.S. cars and planes “culture” in the economy, this paper elaborates on how building a HSR system may help U.S. advance towards environmental sustainability in transportation, make a break from the status quo, and create a more balanced, multimodal transportation system that will improve the quality and efficiency of travel.