Consideration of transport logistics hubs in freight transport demand models

Abstract

Introduction: The increasing importance of logistics and its effects on transportation processes have been considered in freight transport demand modelling by new model developments incorporating several logistics aspects. However, transport logistics hubs – hubs without storage function that are primarily used for transhipment – seem to be not considered adequately in most freight models although they are crucial for freight transport. Currently it is not apparent which models do consider transport logistics hubs and how they do. The aim of this article is, therefore, to review how transport logistics hubs are considered in freight transport demand models and to discuss remaining gaps and challenges. Methods: Based on an extensive literature review a broad and internationally oriented analysis of transport models has been conducted. More than 100 models were examined regarding their consideration of logistics in general and transport logistics hubs in particular. Results: The article points out the major importance of transport logistics hubs within freight transport and, thus, underpins the fact that they should also be considered sufficiently in freight demand models. It reveals that there are numerous models in application worldwide and that most of these models do not consider logistics or hubs. Only few models integrate logistics hubs, in general, and transport logistics hubs in particular. Furthermore, the consideration of transport logistics hubs within these models differs quantitatively (number and types of hubs) but also qualitatively (detail of hub integration) – also depending on model properties (e.g., scale of analysis, resolution or level of aggregation). Conclusions: Within freight transport processes, transport logistics hubs gained growing empirical significance in the recent past. This implies a major relevance to consider them in demand modelling, too. However, the article reveals that the integration of transport logistics hubs lags behind their empirical significance and that there are certain restrictions which hamper an adequate integration. The potential of many models is limited by reason of data availability. The lack of detailed data remains a major challenge that is, frankly, not new to the freight modelling community. Closing this data gap will help to consider transport hubs adequately and, thus, increase accuracy of models which would enable policy decision-makers to come to more effective decisions.