Emergency Medical Services (EMS) provide pre-hospital care and transportation to hospitals following an emergency call. Some EMS will also offer inter-hospital transportation services for patients. This paper presents a simulation model based on Urgences-santé, an EMS covering a population of 2.4 million people in Quebec (Canada). The goal of the simulation tool is to produce a highly realistic model that focuses on some of the lesser studied aspects of EMS management. These aspects include relocation, reroute-enabled dispatching, hospital selection, break management, complex priority system, ambulance specialization, and the integration of inter-hospital transport. The simulation tool allows us to measure the impact of changes to the rerouting and relocation policies, as well as to the fleet composition, on the system’s performance using what-if analysis.