A multi-period dynamic location planning model for emergency response

Abstract

We investigate a multi-period ambulance location problem for an emergency medical service (EMS) provider that routinely aims for high quality medical response in a short period of time. However, both quality and timing of service are very costly goals to achieve. In this research, our goal is to minimize the total operational cost of an EMS organization while maintaining acceptable response times for a newly defined EMS network that consists of supply centers, hospitals, responder locations, and incidents. We propose a new dispatch model, a deferred service model, to analyze the daily operations of ambulances that involve dispatch as needed and redeploy periodically. The main premise of this model is, given incident priority levels, incident demand patterns, and EMS provider resources, to decide which incidents to serve immediately and which incidents to defer to following periods while incurring deferral penalty costs. Additionally, high-priority incidents that are not addressed within the required response window incur delay penalty costs. Considering network size, fleet size, incident patterns, and time-dependent parameters as different factors that may influence the solution, we compare the results in terms of service quality, response time, and total cost through extensive experimentation. Experimental results indicate that sending the closest ambulance to an incident site is not always the best choice.