Emergency Department (ED) overcrowding has been a major problem in the United States for almost two decades. Accordingly, numerous efforts have been put forth into eliminating the adverse effects that come along with it, such as long waiting times (WT), patients leaving without being seen (LWBS) and deterioration of quality of care. From the published patient flow improvement interventions, we focus on strategies that are widely discussed in the relevant literature: fast track, physician triage and team triage. The effectiveness of these interventions is shown through mostly observational and a limited number of controlled studies, where only a specific intervention is studied. However, these “success stories” help little when alternatives are not compared properly. To overcome this problem, we propose a simulation approach to examine these interventions in a controlled environment and to enable the sensitivity analyses of critical ED parameters such as resources or patients’ inputs, and performance measures. The impact on patients of different urgency levels is also addressed so that generalized conclusions on the effectiveness of interventions can be made to guide future implementations.