Role-playing games as a mean to validate agent-based models : an application to stakeholder-driven urban freight transport policymaking

Abstract

Agent-based models (ABMs) are widely used to replicate transport environments accounting for interaction among stakeholders. Validation of ABMs implies assessing the extent to which the model, from assumptions to results, is capable of approximating reality. To this end, different methods have been proposed, but yet no widely accepted procedure has emerged. This paper addresses this problem and suggests using a procedure based on role-playing games (RPGs). A first application is described with the intent of providing a preliminary contribution to validate an ABM trying to mimic stakeholders’ interaction in a multi-level decisionmaking process in the context of urban freight transport policy-making. The aim is twofold: (1) understand if the structure of the model and the opinion dynamics envisioned are consistent with a real negotiation process, (2) verify if the results derived from the ABM effort are in line with those derived from a real-life experiment. Results of the first preliminary experiment show that the model seems capable of reproducing real-world processes and confirm that well-thought-out RPGs can contribute to validating ABMs. Keywords: city logistics, stakeholder engagement, participatory simulation, model validation, discrete choice models