Heuristic algorithms based on the isochron analysis for dynamic relocation of medical emergency vehicles

Among the wide range of medical services, prehospital health care is one of the most relevant, as it usually involves an emergency situation. The qualified medical team is dispatched to the scene of the incident as soon as possible. One of the most influential factors in response time depends on where the ambulances are stationed, however, when a medical vehicle is attending an emergency, it becomes unavailable for other calls. Increasing the ambulance fleet is a costly option that does not guarantee efficiency. An alternative solution is the relocation of available ambulances to increase the population covered by them. Obtaining the optimal solution in real time is not feasible for this problem. Therefore, this work addresses the problem of dynamic relocation of ambulances through the design and development of heuristic tools. The isochron overlap analysis defines possible scenarios that may occur when ambulances become unavailable for emergencies and determines the appropriate conditions to carry out the relocation of ambulances. Computational experiments are run using a benchmark of instances based on the characteristics of a real Emergency Medical Service. Based on the results of the study, we can conclude that the designed relocation algorithms perform better than if there was no relocation strategy.