CFD is commonly used in the design process of smoke control systems of transportation infrastructure (tunnels, car parks, railway stations, metro systems). It is usually performed as a part of some sort of performance-based design framework. However, the limitations of the tool related to large-scale projects are often not well recognized, sometimes leading to expectations towards the complexity of the analyses that cannot be met. In this talk, we will crash ‘what we can really simulate with CFD’ with the expectations of non-fire stakeholders. This covers not only the uncertainties of the CFD analyses and the most common challenges in setting up the simulations but also the costs involved with the human work and computer solving time required in more advanced projects. Furthermore, we will try to provide insight into exciting future trends such as the use of transport simulations to generate traffic boundary conditions, computer-aided generation of parametric case studies as well as the use of AI as a supporting tool in the PBD process.