An optimization approach for dispatching and relocating EMS vehicles

Abstract

We consider the problem of dispatching and relocating EMS vehicles during a medical emergency such as a influenza outbreak when the demand for EMS vehicles increases. In order to better utilize EMS vehicles’ capacity and based on our discussions with EMS personnel, we assume that ambulances can serve more than patient where appropriate. Specifically, a vehicle transporting a high-priority patient cannot serve another patient until service to the high-priority has been completed. However, a vehicle transporting a low-priority patient can be rerouted to pick up one more patient. The objective is to minimize the total travel costs, the penalty of not meeting response time window for patients, and the penalty of not covering census tracts. Integer linear and nonlinear program models and an approximation model are proposed. Numerical examples show that the proposed solution algorithm implemented with general-purpose solvers is efficient for solving large size problems, and thus is suitable for use in a real time decision support system.