National and international freight transport models: overview and ideas for further development

This paper contains a review of the literature on freight transport models, focussing on the types of models that have been developed since the nineties for forecasting, policy simulation and project evaluation at the national and international level. Models for production, attraction, distribution, modal split and assignment are discussed in the paper. Furthermore, the paper also includes a number of ideas for future development, especially for the regional and urban components within national freight transport models

Designing sustainable cold chains for long-range food distribution: Energy-effective corridors on the Silk Road Belt

Modern food production-distribution processes represent a critical stressor for the environment and for natural ecosystems. The rising flows of food across growing and consumption areas couple with the higher expectations of consumers for the quality of products and compel the intensive use of refrigerated rooms and transport means throughout the food supply chain. In order to aid the design of sustainable cold chains that incorporate such aspects, this paper proposes a mixed integer linear programming model to minimize the total energy consumption associated with the cold operations experienced by perishable products. This model is intended for food traders, logistics practitioners, retail managers, and importers collaboratively called to design and plan a cost and environmentally effective supply strategy, physical channels, and infrastructures for cold chains. The proposed model is validated with a case study inspired by the distribution of two example food products, namely fresh apples and ice cream, along the New Silk Road connecting Europe and China. The illustrated analysis investigates the effect of alternative routes and transport modes on the sustainability of the cold chain. It is found that the most energy-efficient route for ice cream is via rail over a northern route and, for apples, is via a southern maritime route, and, for these two routes, the ratios of the total energy consumed to the energy content of the food are 760 and 913, respectively. By incorporating the energy lost due to the food quality decay, the model identifies the optimal route to adopt in accordance with the shelf life and the conservation temperature of each product

Systemic design of multidisciplinary electrical energy devices: a pedagogical approach

In this paper, we present a complete educative project for illustrating the design and the analysis of hybrid electrical systems. It is based on the study of an ElectroHydrostatic Actuator for flight control application, fed by a power supply associating a PEM fuel cell with a ultracapacitor storage. This system is controlled to achieve a typical energy management strategy of this multi source structure. Step by step, student can faces typical issues relative to the design of heterogenous and multidisciplinary devices by achieving eight pedagogical objectives. These eight targets are focused on methodological approach for multi domain modelling (Bond Graphs), causal analysis, but also on simulation of complex heterogeneous systems. A typical hybrid system feeding an ElectroHydrostatic Actuator (EHA) for flight control application has to be designed which drives students towards other pedagogical objectives: system based device sizing (fuel cell and ultracapacitor), energy management, system analysis

New trends on urban goods movement: Modelling and simulation of e-commerce distribution

In this paper, a modelling framework to complete the recent scientific works on urban goods modelling is proposed. More precisely, we introduce a substitution procedure that estimates the number of trips and the corresponding travelled distances for shopping drive, home delivery and reception points' strategies. Moreover, an appraisal of scenarios is proposed in order to study how these three new forms of proximity delivery services impact on the overall urban goods movement distribution. Starting from four extreme situations, we introduce more realistic scenarios in order to find a suitable combination of delivery strategies. All the scenarios are simulated using the proposed framework, and the main traffic issues related to e-commerce distribution channel are discussed. The best realistic combination promotes the joint usage of home deliveries and proximity reception points and allows a reduction of about 13% of the road occupancy rates in urban areas.urban goods movement, modelling, shopping trips, e-commerce

Agro-terrorism and the Grain Handling Systems in Canada and the United States

The grain handling sector in Canada and the United States is vital to agriculture and trade. In a typical year on the Canadian prairies, about 140,000 producers deliver some 20 to 30 mmt of grain for export to primary elevators. In the United States, about 2.1 million producers deliver about 300 mmt of grain to primary elevators. Canadian grain is moved to export position using more than 400,000 hopper cars and marine containers, where about 1,200 ships per year are loaded. In the United States, about 1.08 million rail carloads of grain are originated per year, and about 23 mmt of grain are shipped on barges per year. These U.S. figures are in addition to trucks, which, more so than in Canada, are also used to deliver grain to primary processors and to terminal and export markets. The volume of grain trade gives rise to concern about risks of terrorism in the sector.(1) From a security perspective, the grain, pulse and oilseed supply chain is noteworthy because much of it is characterized by relatively long-term, insecure, bulky storage (particularly on farms) along with numerous modal and inter-modal product transfers. These factors suggest there are many places where chemical or biological contaminants could be introduced into this supply chain. From the perspective of the United States, security throughout the Canadian system as well as the U.S. system is a concern, since cross-border traffic in these products is significant, with an average of about six million tonnes of grain products alone imported into the U.S. each year (USDA-FAS, 2003). Numerous interventions to enhance food safety and mitigate the risk of terrorism have been adopted or are in the process of being developed. Some of these are private initiatives and voluntary, as a component of firm-level security processes. Others are being adopted in response to legislated initiatives. The stakes are large, and there are likely to be substantial differences in costs and effectiveness of different approaches.Agricultural and Food Policy, Food Consumption/Nutrition/Food Safety,

Uncertainties in Forecasting: The Role of Strategic Modeling to Control Them

The growing concern about environmental depredations from transport activity at short-range and long-range horizon calls for policies aiming at reorientation of travel demand trends. However every transport policy is subject to risks, environmental or financial ones, and has often long-range effects. This explains the renewed interest in tools which allow detection of these risks and their consequences. There is however a methodological challenge in the elaboration of these simulation tools because we have to take into account many different uncertainties.This paper analyzes the uncertainties associated with transport forecasts using a strategic model recently developed for Lyon's conurbation. Different sources of error and uncertainly are tested and compared by means of the model. It is argued that a strategy of systematic exploration of uncertainly is the preferred way to cope with it and to detect long-term risks associated with transport policy.Travel modelling ; Strategic planning ; Urban area ; Uncertainty ; Forecasting

A Lagrangian discretization multiagent approach for large-scale multimodal dynamic assignment

This paper develops a Lagrangian discretization multiagent model for large-scale multimodal simulation and assignment. For road traffic flow modeling, we describe the dynamics of vehicle packets based on a macroscopic model on the basis of a Lagrangian discretization. The metro/tram/train systems are modeled on constant speed on scheduled timetable/frequency over lines of operations. Congestion is modeled as waiting time at stations plus induced discomfort when the capacity of vehicle is achieved. For the bus system, it is modeled similar to cars with different speed settings, either competing for road capacity resources with other vehicles or moving on separated bus lines on the road network. For solving the large-scale multimodal dynamic traffic assignment problem, an effective-path-based cross entropy is proposed to approximate the dynamic user equilibrium. Some numerical simulations have been conducted to demonstrate its ability to describe traffic dynamics on road network.multimodal transportation systems; Lagrangian discretization; traffic assignment; multiagent systems

The cost of being landlocked : logistics costs and supply chain reliability

A large proportion of the least developed countries are landlocked and their access to world markets depends on the availability of a trade corridor and transit systems. Based on empirical evidence from World Bank projects and assessments in Africa, Central Asia, and elsewhere, this paper proposes a microeconomic quantitative description of logistics costs. The paper theoretically and empirically highlights that landlocked economies are primarily affected not only by a high cost of freight services but also by the high degree of unpredictability in transportation time. The main sources of costs are not only physical constraints but widespread rent activities and severe flaws in the implementation of the transit systems, which prevent the emergence of reliable logistics services. The business and donor community should push toward implementation of comprehensive facilitation strategies, primarily at the national level, and the design of robust and resilient transport and transit regimes. A better understanding of the political economy of transit and a review of the implementation successes and failures in this area are needed.Transport Economics Policy&Planning,Transport and Trade Logistics,Common Carriers Industry,Economic Theory&Research,Rural Roads&Transport

Strategies for dynamic appointment making by container terminals

We consider a container terminal that has to make appointments with barges dynamically, in real-time, and partly automatic. The challenge for the terminal is to make appointments with only limited knowledge about future arriving barges, and in the view of uncertainty and disturbances, such as uncertain arrival and handling times, as well as cancellations and no-shows. We illustrate this problem using an innovative implementation project which is currently running in the Port of Rotterdam. This project aims to align barge rotations and terminal quay schedules by means of a multi-agent system. In this\ud paper, we take the perspective of a single terminal that will participate in this planning system, and focus on the decision making capabilities of its intelligent agent. We focus on the question how the terminal operator can optimize, on an operational level, the utilization of its quay resources, while making reliable appointments with barges, i.e., with a guaranteed departure time. We explore two approaches: (i) an analytical approach based on the value of having certain intervals within the schedule and (ii) an approach based on sources of exibility that are naturally available to the terminal. We use simulation to get insight in the benefits of these approaches. We conclude that a major increase in utilization degree could be achieved only by deploying the sources of exibility, without harming the waiting time of barges too much