Ambulance Diversion (AD) has been an issue of concern for the medical community because of the potential harmful effects of long transportation; however, AD can be used to reduce the waiting time in Emergency Departments (EDs) by redirecting patients to less crowded facilities. This paper proposes a Simulation-Optimization approach to find the appropriate parameters of diversion policies for all the facilities in a geographical area to minimize the expected time that patients spend in non-value added activities, such as transporting, waiting and boarding. In addition, two destination policies are tested in combination with the AD policies. The use of diversion and destination policies can be seen as ambulance flow control within an emergency care system. The results of this research show significant improvement in the flow of emergency patients in the system as a result of the optimization of destination-diversion policies compared to not using AD at all.