Evaluation of Relocation Strategies for Emergency Medical Service Vehicles

Abstract

Managers of emergency medical service (EMS) vehicles position their fleets to provide quick response to potential emergencies. Deployment strategies for positioning a fleet, typically static, do not account for variation of demand patterns over time and changes in travel times over the course of a day across the network. Network states can vary significantly and warrant redeployment to serve the entire community better. A relocation strategy that temporarily realigns the EMS fleet in response to these changes can improve system performance. This paper quantifies the benefits of considering relocating EMS vehicles between calls. Because there are costs associated with repositioning the vehicles, trade-offs between improved coverage and cost must be considered. Relocation strategies that consider system uncertainty are compared with static deployment strategies. A real-world analysis is conducted using emergency call data from Montreal, Canada. Practical methodology is proposed to address a real-world optimization problem, including ways to resolve multiple conflicting objectives, analyze systemwide performance probabilistically, and solve large-scale integer programs.