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This paper aims to examine the sustainability of smallholders’ citrus supply chain characterized by low coordination and the need to reinforce producers’ welfare, through optimization-based decision support method in the field where logistics specialization and global sustainability are required by agricultural producers. More specifically, a mixed-objective and multi-objective linear programming model is developed to achieve a sustainable balance: at the economic level, to reduce the logistics costs associated with the production chain as well as to reduce the environmental impacts in the form of carbon dioxide emissions generated during transport, while at the social level, integration through job creation into a three-echelons fruit supply chain including producers, intermediaries and retailers. The model is applied to four scenarios, whose analyses determine the importance of supply chain costs that cannot be neglected but which lead to an optimum that also reduces environmental burden and increases social welfare. In conclusion, the integration of opposing approaches represented by this model enables the improvement of the performance of the supply chain studied.

Resumen Contexto: Los programas de asistencia alimentaria (PAA) producen y distribuyen alimentos o complementos nutricionales para la reducción de la desnutrición en población vulnerable. En ellos, el sistema de distribución del PAA permite conectar la oferta de asistencia con la población objetivo. Esta investigación busca explorar las relaciones y la articulación entre los elementos del sistema de distribución y la eficacia de un PAA altamente ligado a la población infantil, denominado “Bienestarina Más®” en Colombia. Método: La relación entre la eficacia del programa y el sistema de distribución se realiza triangulando datos reales de las entregas del PAA y estadísticas poblacionales oficiales. A su vez, las capacidades de los sistemas de información usados para la distribución son contrastadas con el alcance del sistema, usando fuentes oficiales y manuales de usuario. Resultados: El análisis muestra potencial de mejora en la cobertura de la región suroccidental del país,brechas entre la oferta y la demanda, en especial ante el análisis desagregado de datos, flujos de carga poco coherentes y diferencias entre el alcance del PAA y el alcance de los sistemas de acceso al programa y trazabilidad de la carga. Conclusiones: Este artículo muestra cómo fallas en la articulación entre los procedimientos de acceso,los perfiles sociales de la población, las asignaciones de los flujos de carga y las tecnologías de la información para el reconocimiento del usuario y el seguimiento de la carga pueden afectar la eficacia en la atención a la población infantil. Agradecimientos: Los autores agradecen a Colciencias por la financiación del proyecto de investigación registrado bajo contrato 0340-2013 y a la Universidad Nacional de Colombia por las fuentes de fondos otorgadas bajo convocatoria conjunta Unal-UdeC, 2017. Abstract Context: Food Assistance Programs (FAP) produce and distribute food to fight malnutrition on vulnerable populations. FAP distribution system allows connecting the supply with the vulnerable population demand. This research explores the links and relations between the distribution system components and the FAP’s efficacy. The research is focused on a FAP called “Bienestarina Más®” in Colombia, highly associated with childhood welfare. Method: The relations between the distribution system and program efficacy is analyzed comparing real FAP delivery data and official population statistics. The capabilities of the information systems are compared with the FAP scope using user manuals and official reports. Results: The analysis shows improvement potential in the coverage of the Colombian South-West region,gaps between offer and demand, especially when the study evaluates disaggregated data. Also, the research found a lack of coherence in the freight flows and the difference between FAP’s scope and the information systems used for user register-recognition and freight traceability. Conclusions: The research shows a lack of coordination between FAP access procedures, the population social profiles, the freight flows allocations and the scope of the information technologies. Thecoordination failures affect the efficacy of the program the childhood population attention. Acknowledgements: COLCIENCIAS financed the research, grant number 0340-2013 and Universidad Nacional de Colombia - UDEC ( Joint Research Projects CALL - 2017).

PurposeThe purpose of this research is to determine the convenience of using a contract model as an integration mechanism for decision-making in a decentralized supply chain of small agricultural producers in a developing country, taking as hypothesis coordinated chain achieves better management. The analysis is based on information obtained by direct inquiry to 99 small producers in the region, about planning, production, marketing and distribution in the chain, supplemented with secondary information sources.Design/methodology/approachAs a methodology an analysis of maturity in the chain based on the Capability Maturity Model Integration is done, whose evaluation is later analyzed as a fuzzy logic model, with the support of the fuzzy logic of the MATLAB toolbox, to study the convenience of the use of the contract against the other mechanisms, and to establish an approximation to the level of readiness of the chain toward integration.FindingsResults obtained show that the small farmer supply chain studied, from a maturity perspective, has a strong disposition for the use of contracts as an integration mechanism.Research limitations/implicationsThe supply chain for small producers presents a high dispersion, little consolidated offer capacity and lack of coordination. Limitations in terms of information and criteria unification are a challenge for future research. Results have socioeconomic implications for small producers and can serve as a guide to formulate policies by the governments in Latin American countries.Practical implicationsAs practical implications, it can be stated that the use of supply contracts is a real mechanism that can be implemented in this type of chain, to break the mistrust between the echelons and improve the supply chain performance. This research will allow to establish support programs from local governments for the sustainability and improving income of small producers. In addition, contracts will allow to formalize the linkage of small producers to a sustainable commercial network.Social implicationsSmall agricultural producers in developing countries live in unfavorable conditions, with socioeconomic limitations. This work offers an alternative for their productive activity development that will allow them access to marketing chains in a safe way and improve their living conditions.Originality/valuePrevious studies related to the maturity toward the chain integration and fuzzy logic as a hybrid methodology, were not found in the literature, and less even applied to a chain of small agricultural products.

Performant planning and integration of Urban Logistics Spaces (ULS) in logistics networks are key to optimising the circulation of goods in cities. During the last three decades, several documents ...

This paper aims to analyze the impacts of a backup agreement contract on the performance of a small agricultural producers’ citrus supply chain. A backup agreement contract, which ensures for each echelon that a quantity of products will be bought independently of real demand, is proposed to coordinate a three-echelon supply chain, aimed at improving income. After presenting an overview of the literature that shows various coordination mechanisms but no backup agreement proposals for supply chain coordination, this paper develops a decentralized three-echelon supply chain facing stochastic customer demand and includes the backup agreement as a coordination mechanism to guarantee a balanced relationship between the chain members. The model is tested in a real case study in Colombia, and a sensitivity analysis is provided. Results show that a backup agreement contract coordinates the small agricultural producers’ supply chain and improves income for each echelon, especially for the small producer. However, the economic mechanism complexity can limit coordination among echelons, mainly because of a lack of trust and consolidated supply capacity from small farmers. The foregoing requires the development of an associative structure by small producers, which is proposed as future research work.

International audience; The production and distribution of Bienestarina to the vulnerable population of Colombia is one of the strategies of the Colombian Institute of Familiar Wellness (ICBF) to fight malnutrition, especially among children. This case is a good example of establishing food security and social improvement logistics that merits particular attention. The chapter presents an analysis of the Bienestarina supply chain based on the four elements: steering, organization, development, and financial issues. First, an overview of social improvement logistics and the Bienestarina context is provided. Second, theoretical frameworks related to the case are presented. Third, the case is described on the basis of the proposed analysis framework. Finally, generalization issues and conclusions allow the authors proposing the first characterization of social improvement logistics.

Made available in DSpace on 2022-04-28T19:28:43Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-06-01 This paper provides a framework to analyze the maturity of humanitarian logistics systems to face crisis situations related to recurrent events, and thus to identify the main areas of action and the community needs in terms of crisis logistics planning. First, the main notions of humanitarian logistics systems planning, and the theoretical contribution of maturity models are presented. Second, a maturity model for humanitarian logistics systems is proposed and the main categories of elements defining maturity extracted from literature. Then, the methodology to define the main elements of the maturity model via evidence is presented. This methodology combines a literature overview, a documentary analysis, and the development of three case studies, two located in Colombia and one in Peru. The main elements that characterize capability maturity model in humanitarian logistics systems facing recurrent crises are identified, from which the administration of donations, design of a distribution network, and the choice of suppliers are highlighted. The practical implications of the framework are proposed to allow its use to anticipate humanitarian logistics system for future crises. The framework allowed a first analysis guide and will be further extended. Supply Chain Purcahsing and Project Management Department Excelia Group, La Rochelle Business School Engineering Department Universidad del Pacifico Engineering Department Pontifica Universidad Católica del Peru Environmental Engineering Department Sao Paulo State University School of Business and Public Accounting Universidad Nacional de Colombia Département Génie de l'Environnement et des Organisations Institut Henri Fayol Ecole des Mines de Saint-Etienne Environmental Engineering Department Sao Paulo State University

International audience; This chapter studies the implication of aggregating establishments by categories with different levels of detail for modeling FTG. To this effect, the chapter conducts an assessment of freight trip generation (FTG) patterns homogeneity inside activity-based grouping. The method implemented is econometric in nature, which allows the assessment of the statistical significance of variables representing commercial activity sectors and sub-sectors. The results show that for some sectors the traditional high-level aggregation includes sub-sectors with homogenous FTG patterns and thus produces appropriate models; in some other cases (e.g., retail, manufacturing), the sub-sectors have different FTG patterns and thus more detailed data is needed to calibrate accurate models. This research can be used to enhance the efficiency of data collection, as it identifies some sub-sectors that need larger efforts for data collection, and some other categories where FTG homogeneity allows for less detailed data collection without hampering the quality of the models.

Many recent studies stress the importance of freight facility location for urban freight movement. Although, tools and reflections are still lacking to shed light on shopkeepers’ location choices. Several reasons, e.g. the implementation of long-term city logistics measures or the threat of commercial rent increasing can lead retail-store keepers to move their business from city centre to surroundings. Therefore, it becomes critical for them as for urban policy makers to have tools for simulating or assessing the effects of such a choice on the business, and on the local economy, land-use and environment. This paper assumes that the shopkeepers’ choices are mainly influenced by whether their customers accept or reject this move. It aims to forecast the choice of customers to remain or not client of a retail store after its relocation in the urban periphery, by predicting the most significant factors, which are likely to influence their decision. Starting from some surveys carried-out before the movement of an actual city centre store in Saint-Etienne, the paper suggests a conditional inference tree rather than other tree-structured models for this analysis. Over the peculiarities of the store and the city, the model estimated and tested in this paper underpins many findings available in the general literature about shopping trips. The results seem to be indicating that not only customers’ residence, but also their shopping trip behaviours and wanderings are to be taken into account in a retail-store location decision.

This paper proposes the methodology of a decision support system to estimate the impacts of retailing development on freight trip generation and shopping trip structure and composition. First, the methodological framework of the shopping trip chain estimation is proposed, i.e. generation, catchment distribution and distance estimation. Then, the proposed zonal freight trip generation model is described and a land use module based on attractiveness and accessibility indicators proposed. An application to the deployment of a set of new retailing poles in Lyon, France, is also presented. Results show that although freight trips remain residual at a global level, shopping trip increase of those three new zones have a non-negligible contribution to the overall traffic. Finally, practical implications and further developments are presented.

International audience; This paper reviews the state of the art in spatial accessibility and attractiveness indicators for urban freight transport and logistics, from a territorial intelligence and analytics viewpoint. It proposes a first typology of indicators and analyzes their potential in Latin American urban planning and development. After presenting the main notions of business intelligence and analytics, as well as a definition of territorial intelligence and analytics, the paper proposes an overview of territorial intelligence indicators, focusing on accessibility and attractiveness indicators, and a typology of five categories of indicators: infrastructure-based indicators, generation-based indexes, distance/ time/cost measures, gravity-based indicators and space-time compatibility indexes. Finally, the main issues for implementing such indicators are presented, in terms of data requirements and potential applications focusing on the Latin American context. El presente artículo presenta el estado del arte sobre indicadores de accesibilidad y de atractividad espacial para el transporte de carga y la logística urbana, desde el punto de vista de la inteligencia y la analítica territorial. El artículo propone una primera tipología de indicadores, y analiza el potencial de su uso en la planeación y desarrollo urbano en Latinoamérica. Tras presentar las principales nociones de inteligencia y analítica de negocios, y proponer una definición de la inteligencia y analítica territorial, el artículo propone una visión de conjunto de los indicadores de inteligencia territorial, con un foco en los de accesibilidad y atractividad, y una tipología con cinco categorías de indicadores: de infraestructura, de generación, de distancia/tiempo/costo, gravitatorios y de compatibilidad espacio-temporal. Finalmente, se presentan las principales cuestiones en la implementación de dichos indicadores, en términos de requerimientos en datos y de potenciales aplicaciones, con un foco en el contexto latinoamericano.

RESUMECet article propose un cadre d’analyse de la mutualisation entre transporteurs basee sur la gestion des capacites residuelles, dans un contexte de livraisons urbaines. Dans un premier temps, l’article dresse un panorama de la recherche sur la mutualisation logistique pour ensuite recadrer le contexte de cette etude : la mutualisation horizontale des livraisons urbaines. Ensuite un cadre d’analyse des impacts de la mutualisation est propose, comprenant les choix et hypotheses, ainsi que la methode analytique d’estimation des impacts de la mutualisation utilisee. Puis, a titre d’exemple, cinq scenarios de mutualisation sont presentes sur lesquels la methode est appliquee. Enfin, les resultats de cette simulation sont presentes et ses principaux resultats sont discutes.

International audience; Ever-growing urban areas and global population movement towards urbanization lead to major concerns regarding urban logistics and last mile operations. In Latin America, the problem becomes critical since volatile emerging economies and unstable political situations, which are common in the region, introduce additional limitations for strong logistics solutions. In the city of Quito (Ecuador), traffic regulations only consider time-schedule restrictions for vehicle mobility without any other policies that benefit urban goods movement. This is in part because there is a lack of knowledge on freight flows, mainly related to the difficulties to retrieve data to that purpose. This paper proposes a freight trip generation analysis in Quito, based on a methodology included in “MIT’s Better Cities for Logistics Toolkit”, which defines specific zones observation and data collection campaigns. More precisely, a procedure combining observation-based and declarative data collection processes is proposed. First, the opportunities of combining both observed and declared data to characterize freight trip generation are addressed on the basis of a literature review. Main issues of combining establishment based surveys and observations are addressed to generalize the proposed framework. Finally, application implications in a transferability perspective to other Latin American countries are addressed.

International audience; The purpose of this paper is to identify which environmental criteria can influence the product demand in a context of business-to-business. These criteria can be related to the product's environmental characteristics, to the organization strategies or green practices developed by the firms and to the supplier selection process.Building the conceptual framework from the literature review, a set of environmental criteria were extracted, selected and validated. These criteria were used as a basis for the definition of a questionnaire survey that was sent to 5820 professionals from the food industry in France. The analysis of the 248 complete answers shows that the environmental characteristics of the product can influence product's demand. The most influential attribute to improve the product's environmental quality that increases the product's demand is the introduction of organic labelled raw materials. Besides, the practices that influence mostly the product demand are related to the geographical proximity with the stakeholders. Moreover, the results show that the most important selection criterion when choosing a supplier is the importance given to the quality and environmental performance of components offered. Hence, we show that in the French food market, as opposite to what is usually assumed in many research works, the carbon emissions yield during the production process and transportation process have still no significant impact on products' demand. Lastly, in this work, we quantify the demand increase that company can achieve when enhancing the environmental quality of its products. We show that the impact of the enhancement of those criteria on the demand can have different aspects. 55.6% of respondents advocate for a demand increase and most of them (33.6%) estimate this increase between 5 and 10% of the initial demand. Finally, some respondents (4.8%) indicate that the enhancement of environmental quality does not necessarily increase the demand. However, without efforts to enhance the environmental quality of their products, the demand can decrease.These findings allowed concluding that the business-customers are becoming more and more exigent by privileging organic labelled and local products and making that the companies analyse the geographical proximity with the stakeholders as a key factor during the selection process. We provide companies managers in food industry with better understanding about the environmental criteria that increase the products demand helping them to target the right decisions and to be efficient in their process of environmental quality enhancement. We also assess and try to quantify and give an estimation about the demand evolution regarding the enhancement of product's environmental quality. Our findings are also helpful for Operational Research community.

International audience; The purpose of this chapter is to study the benefits of collaboration among shippers in less than truckload transportation and to show the role of transhipments in the collaboration. In this chapter, the authors propose a new model for the pickup and delivery problem with transhipment and time windows to study the role of transhipment in the green collaborative transportation. A transportation network with two transportation modes road and sea is considered. Different scenarios are optimized and compared in terms of cost and CO2 emissions: with/without collaboration and with/without transhipment. The proposed model is applied to a case study with real data from three agri-food companies in short sea shipping context. With this model, the total cost and the total amount of CO2 emissions are reduced by using collaboration and transhipment. An experimental study was conducted to illustrate this positive impact.

International audience; This paper explains the first steps of a smart PSS engineering approach, aimed at eliciting stakeholder needs, prototyping the value proposition, representing how the Original Equipment Manufacturer (OEM) will capture value and share it with a collaborative network of stakeholders while identifying and prioritizing risks from the value proposition. The approach addresses two gaps in the field of smart PSS design: (i) the need of visualizing solutions to support the transformation of value propositions for the stakeholders into a contract mechanism supporting value capture by the offering company and (ii) the importance of integrating risk management during the design of Smart PSS value proposition

International audience; Public authorities are increasingly interested in fostering short food supply chains. Starting by increasing the share of local and organic food in school canteens has a big potential but requires the redesign of the physical distribution system to make short food supply chains competitive and sustainable. Food Hubs (FH) have been identified in the literature as enablers of sustainable and efficient food supply chains. This chapter describes the functions and characteristics of FH used for school canteens, and analyses how these FH should be designed to increase local and organic products share in school canteens. The results show that changing allocation from the current one—based on administrative subdivision—to a geographical proximity-based allocation could lead to 25% reductions in vehicle-kilometres travelled.

Part 15: Collaborative Decision-Making in Value Creation Networks; International audience; Several City Logistics (CL) initiatives have emerged in the last two decades with the aim to reduce the negative externalities of freight distribution in urban areas. Such initiatives can be public and/or private but need to not break or impeach current operations efficiency so to not hinder their profitability. In order to provide business value to CL initiatives and thus fostering their long-term success, it is necessary to understand the decision-making of private companies operating in the urban freight ecosystem. This paper proposes an ex-ante assessment and evaluation framework built around the concept of an ecosystem business modelling that includes the decision-making by CL stakeholders. A theoretical framework previously developed is extended to evaluate a collaborative business model of an Urban Consolidation Centre (UCC). Cost-Benefit analysis (CBA is used estimate the impact of the business model configuration. Finally, research and practice implications are also addressed.

This paper proposes a framework to define a zoning strategy taking into account both functional and spatial patterns. This partition allows further development of territorial intelligence analytics indicators, mainly in the context of urban logistics in developing countries. First, the main notions of territorial intelligence and analytics are proposed, as well as the needs of producing standard, transferable spatial and zoning data. Then, the main framework, based on functional and spatial clustering techniques, is presented. After that, the framework is illustrated via an application to the metropolitan area of Lima-Callao, Peru. Results show that functional elementary zones of same type mainly have a continuity, but some actions need to be taken in a small set of zones. Finally, main research and practice implications are addressed, showing a generic, replicable methodology based on open data.

International audience; PSS offerings are characterized by the presence of uncertainties due to the lack of information, in the design stage of the offer, about future events that the decision makers will face. These uncertainties must be anticipated to validate the profitability of PSS projects. In this paper, an approach to assess uncertainty is presented, then applied to a study case. This approach is an integration of the classical uncertainty management framework together with the quantitative uncertainty assessment framework. In the first part of this article, a literature review on uncertainty identification and assessment in the PSS context is presented. Then, an uncertainty assessment approach is proposed, with the methods and tools to implement it. Finally, the authors describe the results of the application to an industrial case study.

International audience; This chapter deals with data production within the paradox of big-no data in urban logistics. More precisely, the chapter aims to make an overview on data production in urban logistics and present the main issues, as well as a framework, to overcome that paradox. First, the big-no data paradox is defined and motivated. Second, the question of demand and route estimation in urban logistics is examined more in-depth via an overview of current data production methods and techniques used to estimate demand and transport flows. Third, a framework to produce unified databases filling those data lacks is introduced as well as an analysis on how the different data production techniques can be used to overcome that paradox. Finally, research directions regarding urban goods transport data production are provided.

This chapter presents a general framework to assess urban rail logistics suitability via a socio-economic cost-benefit analysis, also called social cost-benefit analysis (SCBA). First, the author proposes an overview on the basic notions of SCBA starting from those of classical cost-benefit analysis (CBA) then identifies and presents the main types of costs and benefits of railway urban logistics services and the related final delivery services associated to them using low emission road vehicles to serve final customers from the railway stops. After that, the main modelling issues needed for SCBA assessment are presented. Finally, as an example of application, the author proposes to assess a scenario of deployment of a freight tramway in Paris, in a possible configuration. The results show the potential of those approaches but also show that it is important to contextualize them and inform the different users about their real capabilities.

International audience; This chapter contributes to the discussion on city access policies via the identification of a set of common beliefs and the relations between vehicle size (related to one of the most popular types of access policy actions) and logistics performance of urban deliveries. First, the author makes an overview of such policies in various European countries, then establishes a non-exhaustive set of common beliefs regarding urban logistics that influence policy making among others. Then, to illustrate the common belief regarding vehicle sizes, the chapter proposes an example of scenario assessment for stating on the usefulness and performance of different vehicles. Results show that there is not a more suitable vehicle type than another, and the use of the different vehicles will depend on the carriers' strategies and choices.

International audience; This chapter proposes an exploratory gravity accessibility analysis applied to urban goods transport in Lyon, France to support public decision choices in terms of retailing land use. The proposed indicator is shopping-trip oriented but with a viewpoint of urban goods transport: it considers freight generation (i.e., commodity quantities) at destination and travel issues between household locations and retailing areas for shopping purposes. First, an overview of accessibility used in both urban personal and goods mobility is made, and the proposed analysis motivated. Second, the main methodological elements are presented, focusing on the modelling issues mobilized for indicator construction. Third, the analysis is applied to the current situation for the urban area of Lyon. Results are presented and discussed. Finally, recommendations to public authorities for land-use and mobility (both for people and goods) policy assessment are proposed.

International audience; Collaborative transportation and logistics pooling are relatively new concepts in research, but are very popular in practice. In the last years, collaborative transportation seems a good city logistics alternative to classical urban consolidation centers, but it is still in a development stage. This chapter proposes a framework for urban logistics pooling ex-ante evaluation. This framework is developed with two purposes. The first is to generate comparable contrasted or progressive scenarios representing realistic situations; the second to simulate and assess them to make a “before-after” comparative analysis. In this framework, a demand generation model is combined with a route optimization algorithm to simulate the resulting routes of the proposed individual or collaborative distribution schemes assumed by each scenario. Then, several indicators are obtained. To illustrate that framework, several scenarios for the urban area of Lyon (France) are simulated and discussed to illustrate the proposed framework possible applications.

International audience; This chapter proposes a decision support system, STG-Sim, that estimates the number of shopping trip chains as well as the related distances to assess the impacts of the retailing structure on the final part of goods transport chains: that of bringing purchased goods to the end-consumer's location. First, the methodological framework of the shopping trip chain estimation is proposed. It includes a generation model (for both motorized and pedestrian trips), a catchment area distribution model (to relate the shopping locations to the household's ones), and a distance estimation procedure. An application to the deployment of four retailing poles (two new ones and two extension ones) in Lyon, France, is also presented. Finally, practical implications and further developments are presented.

International audience; This paper analyzes the impacts of aggregation level and category construction on the relevance and quality of freight trip generation (FTG) models. More precisely, constant generations and functional form models are compared, as well as activity and activity-workforce categories. The paper proposes a method to compare constant generation and functional form models on different category classifications based on MAPE estimations. Functional forms are assessed via linear regression and compared using Pearson coefficient. Results show that the aggregation level has not always a positive impact on the model’s accuracy and the choice of suitable functional form leads to more accurate models.

International audience; This chapter presents four contrasted and near-caricatured scenarios of retail location and distribution, and compares them on the bases of both road occupancy rates and greenhouse gas emissions. Two main families of scenarios are defined: retailing land-use scenarios, based on the location of the different retailing activities of a city; and end-consumer delivery organizational scenarios, based on the definition of new services to deliver end-consumers, at home or to reception points. Those scenarios are simulated using an integrated approach combining inter-establishment goods transport flows, shopping trips, and end-consumer deliveries. The assessment approach is able to show the relation between several aspects of retailing deployment (mainly store location, catchment area's supply, and urban retailing planning policies) and both upstream distribution of goods to retailers and downstream usage of private vehicles for shopping. Although scenarios are extreme and contrasted, they are able to identify the limits and forces of the different retailing strategies in urban zones.

International audience; This chapter proposes an overview of the main urban goods transport movement approaches in more than 40 years of research in the field. A state of the art on urban goods transport modelling is proposed in the form of a chronology to examine the main four periods in urban goods transport modelling, the main approaches, and the main schools of thinking. After that, the main dominant approaches are defined and presented. The author observes that, although in literature there is the feeling that no unified approach is dominating the field, several dominant approaches can be found: the first concerns demand generation models, the second the way generation is linked to route definition and construction, the third to the units used, and the fourth to the use of origin-destination synthesis when few data are available and classical models are not able to be deployed. Finally, as a conclusion, the paper shows on the current state of the field, which has achieved various advances, shows the capacity to innovate in the near future.

International audience; This chapter presents the main notions of two-echelon vehicle routing (2E-VRP) in relation to city logistics. After introducing vehicle routing and the main single-echelon problems and variants, the two-echelon version is presented and two different models proposed: one based on commodity flow and the other on vehicle flow modelling). Several instances are solved with those models and the results are compared and discussed. That comparison illustrates the difficulty of using this type of models to obtain results to that problem, and motivates the need of developing suitable algorithms. For that reason, an overview of heuristic methods to solve two-echelon vehicle routing problems is made, as well as an introduction of other related problems which are similar and interesting, relating in all cases the presented methods and problems to city logistics needs and goals.