Impact of generalized travel costs on satellite location in two-echelon vehicle routing problem

In this paper we address the Two-Echelon Vehicle Routing Problem (2E-VRP), the variant of VRP where freight is delivered from depots to intermediate satellites, and then it is delivered to customers while minimizing the global routing costs of the overall two-echelon network. The goal of this work is to address more realistic situations in urban freight delivery where the travel costs are not only given by distances, but also by other components, like fixed costs for using the arcs, operational costs, and environmental costs. We introduce a generalized travel cost that may combine different components, e.g., operational, environmental, congestion, etc. We then analyze how the different components of the generalized cost affect the satellite location in the 2E-VRP and whether and under which conditions the Two-Echelon approach dominates the Single-Echelon on

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Technical Editors Paulo Armando Victória de Oliveira, Jorge Manuel Rodrigues Tavares, Paulo Belli Filho

TTI Researchers Develop Curriculum for Transportation Emissions and Health

Researchers in the Texas A&M Transportation Institute\u2019s (TTI\u2019s) Center for Advancing Research in Transportation Emissions, Energy, and Health (CARTEEH) have developed a cross-disciplinary course titled Traffic-Related Air Pollution: Emissions, Human Exposures, and Health. A Tier-1 University Transportation Center program, CARTEEH is funded by the U.S. Department of Transportation\u2019s Office of the Assistant Secretary for Research and Technology (OST-R) and focuses on the intersection of transportation and health, including the growing impact of transportation emissions (see figure 1) on human health. TTI leads the CARTEEH consortium, which consists of four partner universities: Johns Hopkins University, Georgia Institute of Technology, University of Texas at El Paso, and the University of California, Riverside. Transportation and health have historically been viewed as two distinct fields of education, research, and practice. Students, researchers, and practitioners in each field are typically taught their respective subject matter without touching on the other. There is a growing need, however, for cross-disciplinary training at the intersection of transportation and health. To deal with the complexities of how transportation impacts public health, we need new curricula that recognizes this relationship

Development of an Emission-Based Selection Algorithm to Optimize Variable Message Sign Locations

69A3551747128This project devised an optimization method to site variable message signs (VMSs) for traffic incident management. The optimization objective is to maximize the economic utility of each VMS, considering both the monetary value of time and value of emissions. The method includes an integrated traffic and emissions simulation module and an optimization module that stochastically sample from real-world incident data. The method was applied to El Paso, Texas, as a case study. The case study demonstrated convergence of the optimization process, arriving at a stable set of optimal sites given various input assumptions. The optimally sited VMSs showed favorable societal return on investment in congestion relief and emissions reduction

How market structure drives commodity prices

We introduce an agent-based model, in which agents set their prices to maximize profit. At steady state the market self-organizes into three groups: excess producers, consumers and balanced agents, with prices determined by their own resource level and a couple of macroscopic parameters that emerge naturally from the analysis, akin to mean-field parameters in statistical mechanics. When resources are scarce prices rise sharply below a turning point that marks the disappearance of excess producers. To compare the model with real empirical data, we study the relationship between commodity prices and stock-to-use ratios in a range of commodities such as agricultural products and metals. By introducing an elasticity parameter to mitigate noise and long-term changes in commodities data, we confirm the trend of rising prices, provide evidence for turning points, and indicate yield points for less essential commodities

Distance-based emission factors from vehicle emission remote sensing measurements

Vehicle emission remote sensing has the potential to provide detailed emissions information at a highly disaggregated level owing to the ability to measure thousands of vehicles in a single day. Fundamentally, vehicle emission remote sensing provides a direct measure of the molar volume ratio of a pollutant to carbon dioxide, from which fuel-based emissions factors can readily be calculated. However, vehicle emissions are more commonly expressed in emission per unit distance travelled e.g. grams per km or mile. To express vehicle emission remote sensing data in this way requires an estimate of the fuel consumption at the time of the emission measurement. In this paper, an approach is developed based on vehicle specific power that uses commonly measured or easily obtainable vehicle information such as vehicle speed, acceleration and mass. We test the approach against 55 independent comprehensive PEMS measurements for Euro 5 and 6 gasoline and diesel vehicles over a wide range of driving conditions and find good agreement between the method and PEMS data. The method is applied to individual vehicle model types to quantify distance-based emission factors. The method will be appropriate for application to larger vehicle emission remote sensing databases, thus extending real-world distance-based vehicle emissions information

Beyond the public and private divide: Remapping transnational climate governance in de 21th century

This article provides a first step towards a better theoretical and empirical knowledge of the emerging arena of transnational climate governance. The need for such a re-conceptualization emerges from the increasing relevance of non-state and transnational approaches towards climate change mitigation at a time when the intergovernmental negotiation process has to overcome substantial stalemate and the international arena becomes increasingly fragmented. Based on a brief discussion of the increasing trend towards transnationalization and functional segmentation of the global climate governance arena, we argue that a remapping of climate governance is necessary and needs to take into account different spheres of authority beyond the public and international. Hence, we provide a brief analysis of how the public/private divide has been conceptualized in Political Science and International Relations. Subsequently, we analyse the emerging transnational climate governance arena. Analytically, we distinguish between different manifestations of transnational climate governance on a continuum ranging from delegated and shared public-private authority to fully non-state and private responses to the climate problem. We suggest that our remapping exercise presented in this article can be a useful starting point for future research on the role and relevance of transnational approaches to the global climate crisis

Making New Mobility a Win for Public Health

69A3551747128Designing mobility interventions to improve public health requires a framework that formulates strategies for the deployment of mobility to maximize the potential for cross-cutting public health impacts. Researchers developed such a framework using a combination of epidemiology and simulation modeling. A case study is presented to demonstrate how a strategic dose of mobility could improve food access for the South Baltimore community of Cherry Hill

Forest regeneration on European sheep pasture is an economically viable climate change mitigation strategy

Livestock production uses 37% of land globally and is responsible for 15% of anthropogenic greenhouse gas emissions. Yet livestock farmers across Europe receive billions of dollars in annual subsidies to support their livelihoods. This study evaluates whether diverting European subsidies into the restoration of trees on abandoned farmland represents a cost-effective negative-emissions strategy for mitigating climate change. Focusing on sheep farming in the United Kingdom, and on natural regeneration and planted native forests, we show that, without subsidies, sheep farming is not profitable when farmers are paid for their labour. Despite the much lower productivity of upland farms, upland and lowland farms are financially comparable per hectare. Conversion to 'carbon forests' is possible via natural regeneration when close to existing trees, which are seed sources. This strategy is financially viable without subsidies, meeting the net present value of poorly performing sheep farming at a competitive $4/tCO2eq. If tree planting is required to establish forests, then ~$55/tCO2eq is needed to break-even, making it uneconomical under current carbon market prices without financial aid to cover establishment costs. However, this break-even price is lower than the theoretical social value of carbon ($68/tCO2eq), which represents the economic cost of CO2 emissions to society. The viability of land-use conversion without subsidies therefore depends on low farm performance, strong likelihood of natural regeneration, and high carbon-market price, plus overcoming potential trade-offs between the cultural and social values placed on pastoral livestock systems and climate change mitigation. The morality of subsidising farming practices that cause high greenhouse gas emissions in Europe, whilst spending billions annually on protecting forest carbon in less developed nations to slow climate change is questionable