Modelling scenarios on driving simulators is a critical and complex task for behavioural researchers. It requires specific technical and programming skills, for which researchers are typically not formally trained. The main reason for this complexity is the lack of User-Centred Design (UCD) in scenario authoring tools, including an unintuitive and user-unfriendly interaction environment. This could account for some of the challenges faced by behavioural researchers in achieving their objectives with driving simulators. In this chapter, we discuss the problem in detail and propose a user-centred solution, which has been evaluated by users. We also propose a meta-language and an interoperability framework to generalise our solution, so that our approach could be used on most driving simulators.