An analysis of ambulance location problem from an equity perspective

In this paper, we study the Emergency Medical Services (EMS) vehicle location problem from an equity perspective. We construct several mathematical programming models using a set of objective functions and constraints commonly used in facility location problem literature. Due to the uncertainty involved in incident handling times, travel times, and the occurrence of emergency service demand, we use simulation models to assess the performance measures of the EMS systems resulting from the location models. We assess the equity of the system from a Rawlsian perspective, and we report the disparities in service quality among demand nodes using the Gini coefficient, the variance of region-wise mean response time, and lost demand. We utilize multivariate analysis of variance (MANOVA) to demonstrate the significance of mathematical models and the main and interaction effects of network features, such as the distribution of demand nodes across the plane, the number of vehicles, and incident handling rates. Our analysis offers a comprehensive investigation into the impact of mathematical models and network features on equity in the EMS vehicle location problem. Our findings indicate that the choice of mathematical model significantly influences equity, with certain models yielding more equitable outcomes than others. Additionally, we identify the distribution of demand nodes across the plane as a significant factor affecting equity. Ultimately, our results provide valuable insights for decision-makers responsible for designing and operating EMS systems.