CHOIR in practice

Tactical ambulance location and allocation

Brigitte Werners

Providing high quality emergency medical services (EMS) and ensuring accessibility to these services for the public is a key task for health care systems. Emergency vehicles have to be located and relocated such that emergencies can be reached within a legal time frame respecting the limited budget. Empirical studies show temporal and spatial variations of emergency demand as well as variations of travel times during a day. The numbers of emergency calls within a 24 hours interval differ significantly and show peaks especially during rush hours. Existing models do not consider time-dependency of important model parameters as demand or travel times for EMS-vehicles with the problem of an inefficient use of resources. We propose a data driven mixed-integer linear programming model consider-

ing time and spatial dependent degrees of coverage. This allows a simultaneous optimization of empirical required coverage and minimization of the number of used ambulances, respectively costs. On the basis of a simulation tool, it is shown for large empirical data records that the presented dynamic model outperforms existing static models with respect to coverage and utilization of resources.

Biography: Professor Werners is a Professor of Business Administration at  Ruhr- Universität Bochum, with a focus on Operations Research and Accounting. She is also a Director of the Institute of Management (since 1994) and of the Institute for Security in E- business (ISEB, since 2004). She is a former Dean of the faculty of Economics (2003-2005) and a former Senator of the University (2008-2011). Professor Werners obtained her Diploma in Mathematics, her Master in Operations Research and her PhD in Business Administration from the University RWTH Aachen.