Abstract for: Exploring city hubs by using a qualitative system dynamics approach

The urban logistics system causes negative externalities, such as pollution, noise and congestion, that are a burden to cities. Different concepts are developed and implemented to mitigate these negative impacts. The focus of this research is on one such concept, city hubs, which can reduce congestion and pollution through increased consolidation and shift to less carbon-intensive vehicles. However, their implementation faces multiple barriers, and it is not clear how to overcome them. Our research contribution is to create a qualitative system dynamics model (Causal Loop Diagram, CLD) that uncovers the structure of the urban logistics system and the mechanisms behind these barriers. We achieve this by using different qualitative methodologies for data collection. A group model building workshop is carried out to define the problem. A preliminary model based on the results of this workshop and the literature is created. Interviews with stakeholders are used to validate the model structure. Future work includes creating a quantitative model, that can be used to simulate scenarios and evaluate urban logistics policies. The CLD presented in this paper provides a validated system structure of the urban logistics system, and enables policymakers to understand and discuss the barriers to the implementation of city hubs.