The impacts of congestion on commercial vehicle tour characteristics and costs

Analytical modeling and insights, numerical experiments, and real-world tour data are used to understand the impact of congestion on urban tour characteristics, carriers’ costs, and distance/time traveled. This paper categorizes tours into three classes based on their tour efficiency and variable costs structure. Travel time/distance between customers and depot is found to be a crucial factor that exacerbates the negative impacts of congestion. Travel time variability is a significant factor only when travel time between depot and customers is considerable in relation to the maximum tour duration. For each customer, it is possible to define a dimensionless coefficient that provides an indication of the relative impact of congestion on routing constraints. Congestion also affects carriers’ cost structure, as congestion worsens the relative weight of wages and overtime escalates and the relative weight of distance related costs decrease.     

The impacts of Radio Frequency Identification (RFID) technology on supply chain costs

Radio Frequency Identification (RFID) is regarded as a promising technology for the optimization of supply chain processes since it improves manufacturing and retail operations from forecasting demand to planning, managing inventory, and distribution. This study uses a simulation model to calculate the expected benefits of an integrated RFID system on a three-echelon supply chain obtained through performance increases in efficiency, accuracy, visibility, and security level. The study investigates how the product value, lead time, and demand uncertainty affect the performance of the integrated RFID supply chain in terms of cost factors at the echelon level.     

A location-inventory-pricing model in a supply chain distribution network with price-sensitive demands and inventory-capacity constraints

This paper presents a location-inventory-pricing model for designing the distribution network of a supply chain with price-sensitive demands and inventory-capacity constraints. The supply chain has market power and uses markup pricing. An efficient Lagrangian relaxation algorithm is proposed to solve the model. Our numerical study shows that by moderately increasing the number of possible values for pricing decisions, the model can be used to find near-optimal solutions of a similar location-inventory-pricing problem with continuous pricing decisions. The approach used here to incorporate pricing decisions can be applied to other supply-chain design and planning problems with price-sensitive demands.     

Environmental impacts of commuting modes in Lisbon: A life-cycle assessment addressing particulate matter impacts on health

A life-cycle assessment of commuting alternatives is conducted that compares six transportation modes (car, bus, train, subway, motorcycle, and bicycle) for eight impact indicators. Fine particulate matter (PM_2.5) emissions and health impacts are incorporated in the assessment using intake fractions that differentiate between urban and nonurban emissions, combined with an effect factor. The potential benefits of different strategies for reducing environmental impacts are illustrated. The results demonstrate the need for comprehensive approaches that avoid problem-shifting among transportation-related strategies. Policies aiming to improve the environmental performance of urban transportation should target strategies that decrease local emissions, life-cycle impacts and health effects.     

The impacts of emerging aviation trends on airport infrastructure

The demands on airport infrastructure around the world are both growing and changing. This paper explores what problems these changing demands imply for airports, and how they are coping with them. Growth in demand imposes a problem of allocation of scarce capacity in the short run—how well mechanisms such as the slot system are coping with them is explored. In the long term, increases in capacity are warranted, and how the emerging ownership and regulatory environments for airports will handle these is examined. Changes in patterns of demand will come from new business models, such as low-cost carriers and from new aircraft types, such as the Airbus A380—the implications of these for airports of these are considered. Finally, the issue of airport cost efficiency, and how ownership and regulatory environment impact on it, is examined.     

Future accessibility impacts of transport policy scenarios: Equity and sensitivity to travel time thresholds for Bus Rapid Transit expansion in Rio de Janeiro

The accessibility impacts of transport projects ex-post implementation are generally evaluated using cumulative opportunity measures based on a single travel time threshold. Fewer studies have explored how accessibility appraisal of transport plans can be used to evaluate policy scenarios and their impacts for different social groups or examined whether the results of project appraisals are sensitive to the time threshold of choice. This paper analyzes how different scenarios of full and partial implementation of the TransBrasil BRT project in Rio de Janeiro (Brazil) will likely impact the number of jobs accessible to the population of different income levels. The analysis is conducted under various travel time thresholds of 30, 60, 90 and 120 min to test whether the results are sensitive to the boundary effect of the modifiable temporal unit problem (MTUP). Compared to a partial operation scenario, the full implementation of TransBrasil that extends this corridor into the city center would lead to higher accessibility gains due to network effects of connecting this BRT to other transport modes. Nonetheless, the size of the accessibility impacts of the proposed BRT as well as its distribution across income classes would significantly change depending on the time threshold chosen for the accessibility analysis. Considering cut-off times of 30 or 60 min, both scenarios of TransBrasil would lead to higher accessibility impacts in general and particularly for low-income groups, moving Rio towards a more equitable transportation system. However, under longer thresholds of 90 and 120 min, an evaluation of this project would find much smaller accessibility gains more evenly distributed by income levels. The paper highlights how time threshold choice in cumulative opportunity measures can have important but overlooked implications for policy evaluation and it calls for further research on the MTUP in future transport and mobility studies.     

Evaluation of wider economic impacts of light rail investment on cities

Transport plays a critical role in facilitating competitiveness in post-industrial economies. High quality transport services and infrastructure enhance internal and external connectivity. This research examines published and unpublished evidence of economic impacts of modern light rail (tram and light metro) systems in the United Kingdom and globally. Evidence is considered relating outcomes of investment in light rail systems to: unlocking previously hard to reach sites for development; triggering fresh growth through elimination of significant transport constraints; stimulation of inward investment; extension of labour market catchment areas; reorganisation or rationalisation of production, distribution and land use; and land and property value increase and capture. Urban light rail investment can help regenerate Central Business Districts and boost employment and property prices. Similar rail investments in different locations may not however have the same economic impacts — geography matters. Other conditions in addition to transport investment are required for positive externalities.     

Study design impacts on built environment and transit use research

The different factors examined in studies linking the built environment and transit use explain about half of the variability in findings for travel behavior. Despite many differences in the research design of these studies, it is not known if choices about study design impact theoretical consistency in results and account for some of the unexplained variance between studies. This gap exists because multiple studies must be analyzed together to explore the topic. This study aims to fill this gap, using a sample of data points and statistical models from 146 studies identified through a comprehensive database search.This paper first synthesizes the study design adopted in empirical studies of the built environment and transit use. Meta-regression is then used to identify study design aspects causing significant differences. Selective reporting bias appears to slightly exaggerate estimates for built environment Density and Accessibility. Over 40% of variability in findings for Density and Diversity was explained by study design aspects. These include whether collinearity of variables is accounted for, the specificity of the sample population and transit mode, catchment size; and the number of explanatory variables specified.Overall the average correlations for built environment and transit use are weak (<0.2). Predictions of transit ridership based on built environment factors are likely to be imprecise, so models should be carefully specified. Given the impact of study design, adherence to best practice conventions could reduce variance within studies and dispersion between studies. For ambiguous specification issues, sensitivity testing could be used to generate prediction intervals. Further investigation of factors such as transit mode and catchment size would be useful to determine if there is a theoretically plausible reason to favor certain specifications.     

对煤炭重载铁路车站设计的分析

目前煤炭重载铁路从装车地站型、中间越行站或会让站站型,直到卸车地站型,基本形成了较完善的固定模式,车站设计日渐成熟.分析重载铁路车站设计与普通铁路车站设计方法的共性与特点,对煤炭重载铁路中间站、越行站或会让站设计以及装车站和卸车站的设计进行研究,以利于车站设计更好地满足煤炭重载铁路的发展.     

北京市远景年客运交通模式优化研究

从可持续发展的角度出发,以交通效率为目标函数,以居民出行需求、可达性、道路资源、能源消耗、城市环境容许为约束条件,采用线性规划的方法,对北京市远景年客运交通结构模式进行优化,并根据优化结果提出北京发展客运交通的建议.     

Major environmental impacts of European tourist transport

By merging European passenger transport demand data with international tourism data, a new data model was created, giving insight in the environmental impacts of tourism transport between the places of residence of European Union citizens and their tourist destinations. Analysis with this data model shows that, of the environmental impacts considered (climate change, air quality, noise and nature/landscape), climate change generates more than half of the externalities of tourist transport. Policies with the objective of reducing the external cost of European tourism should focus on measures reducing the impacts of tourist air transportation and intercontinental tourism.     

Regional traffic impacts of logistics-related land use

The outsourcing of logistics activities to logistics service providers leads to a demand for new logistics-related land development. At the moment (minimising) regional traffic generation is not a major decision criterion for site selection and development. For a sound traffic impact assessment, information on trip generation of logistics facilities like transfer depots, distribution centres and warehouses is necessary. Surveys conducted in the case study region Hamburg, Germany, provide such information. Applying the survey results, different logistics land use development scenarios are assessed in this paper. The results show that strategic location of logistics areas can reduce traffic and traffic impacts.     

The possible negative impacts of volunteer tourism

Volunteer tourism is an increasingly popular form of travel that is attracting growing research attention. Nevertheless, existing research has focused primarily on the benefits of volunteer tourism, and many studies have simply involved profiling volunteers or investigating their motivations. However, there are numerous possible negative impacts of volunteer tourism that deserve increased attention from both researchers and project managers: a neglect of locals' desires, a hindering of work progress and completion of unsatisfactory work, a disruption of local economies, a reinforcement of conceptualisations of the ‘other’ and rationalisations of poverty, and an instigation of cultural changes. Copyright © 2009 John Wiley & Sons, Ltd.     

Exploring the dynamic impacts of COVID-19 on intercity travel in China

Many studies have explored the effects of transportation and population movement on the spread of pandemics. However, little attention has been paid to the dynamic impact of pandemics on intercity travel and its recovery during a public health event period. Using intercity mobility and COVID-19 pandemic data, this study adopts the gradient boosting decision tree method to explore the dynamic effects of the COVID-19 on intercity travel in China. The influencing factors were classified into daily time-varying factors and time-invariant factors. The results show that China's intercity travel decreased on average by 51.35% from Jan 26 to Apr 7, 2020. Furtherly, the COVID-19 pandemic reduces intercity travel directly and indirectly by influencing industry development and transport connectivity. With the spread of COVID-19 and changes of control measures, the relationship between intercity travel and COVID-19, socio-economic development, transport is not linear. The relationship between intercity travel and secondary industry is illustrated by an inverted U-shaped curve from pre-pandemic to post-pandemic, whereas that with tertiary industry can be explained by a U-shaped curve. Meanwhile, this study highlights the dynamic effect of the COVID-19 on intercity mobility. These implications shed light on policies regarding the control measures during public health events that should include the dynamic impact of pandemics on intercity travel.     

Investigating the impacts of built environment on traffic states incorporating spatial heterogeneity

Traffic state in the urban network is a direct reflection of the operational efficiency of the urban transportation system. As the busiest period of the day, traffic states during evening peak hours can effectively measure the capacity and efficiency of the transportation system. The primary objective of this study is to investigate how the potential factors affect traffic states during evening peak hours on weekdays. The geographically weighted regression (GWR) approach was proposed to model the spatial heterogeneity of traffic states and visualize the spatial distributions of parameter estimations. Four types of data including traffic state index (TSI) data, point of interests (POIs) data, road features data, and public transport facilities data were obtained from Shanghai in China to illustrate the procedure. According to the results, the GWR model outperformed the ordinary least square (OLS) model in the explanatory accuracy as well as the goodness of fit. The urban form was revealed to have a significant influence on traffic states and strong local variability for parameter estimations was observed. The number of public and commercial POIs, residential POIs, bus routes, bus stops, the average number of lanes, as well as average traffic volumes can significantly affect the traffic states spatially, and the estimated coefficients of each traffic analysis zone (TAZ) vary across regions. The conclusions of this study may contribute to making the planning and management strategies more efficient for alleviating traffic congestion.     

The impact of foldable containers on container fleet management costs in hinterland transport

This paper analyzes the possibility to save container fleet management costs in repositioning empty containers through the use of foldable containers. We model this entire empty container flow as an integer programming problem with different strategies in empty container flow itinerary. The model is used to carry out numerical experiments that optimize the empty container repositioning in the hinterland, where there are serious empty container repositioning problems caused by extremely imbalanced trades. The study finds that foldable containers can substantially save on repositioning costs compared to the use of standard containers.     

The effect of high fuel costs on liner service configuration in container shipping

For shipping activities, not least container shipping, bunker fuel is a considerable expense. In the last 5 years, bunker prices have risen considerably. An increasing bunker price in container shipping, especially in the short term, is only partially compensated through surcharges and will therefore affect earnings negatively. This paper deals with the impact of increasing bunker costs on the design of liner services on the Europe–Far East trade. The paper assesses how shipping lines have adapted their liner service schedules (in terms of commercial speed, number of vessels deployed per loop, etc.) to deal with increased bunker costs. The paper also includes a cost model to simulate the impact of bunker cost changes on the operational costs of liner services. The cost model demonstrates for a typical North Europe–East Asia loop that the current bunker prices have a significant impact on the costs per TEU even when using large post-panamax vessels. The model also shows shipping lines are reacting quite late to higher bunker costs. The reasons that explain the late adaptation of liner services relate to inertia, transit time concerns, increasing costs associated with fixing schedule integrity problems and fleet management issues.     

Travel-time reliability impacts on railway passenger demand: a revealed preference analysis

We study the impact of travel-time reliability on trips made by railway passengers. Unlike most of the studies in this area, which make use of stated preference survey data, we use a revealed preference data set obtained by measuring the railway reliability and the number of season-ticket holders on the Dutch railway network. We make use of six travel-time reliability indicators, including the standard deviation and the 80th minus the 50th percentile of travel time. Our results indicate that the 80th minus the 50th percentile indicator best explains the fluctuations in the number of season-ticket holders. A 10% improvement of this indicator results in a 1.47% increase in the number of season-ticket holders.