CWI research increases efficiency and fairness in Ambulance Planning

PhD student Caroline Jagtenberg of CWI has executed research focused on reducing response time of ambulances. In her thesis Efficiency and Fairness in Ambulance Planning she presents new statistical models and methods, verified by realistic case studies for a Dutch ambulance provider. In emergency situations where every second counts, the timely presence of an ambulance can be a matter of life or death. This research to improve the logistics of Emergency Medical Services (EMS) can contribute to improving the response times of ambulances.

Jagtenberg sheds a different light on the decision process in order to determine which ambulance to send to which incident.  Many researchers and practitioners use the ‘closest  idle’  policy without  questioning  it,  but this is  not  necessarily  optimal. Jagtenberg’s research shows that an  ambulance can be chosen,  such  that  remaining  idle  vehicles  remain  a  good  position  with  respect  to  expected  incidents  in  the  near  future. Jagtenberg: “Although we do not advise all EMS managers to immediately discard the closest idle dispatch method, we do show that the typical argument – that it would not lead to large improvements in the fraction of late arrivals – should be changed.”

Dynamic Ambulance Repositioning

Dynamic ambulance repositioning (proactively relocating idle vehicles in order to reduce response times) appears to improve the fraction of late arrivals compared to the scenario in which each vehicle always returns to its home base significantly.  Not only the performance at the response time threshold is improved, but the whole distribution of response times is shifted to the left. The new method is intuitive and easy to implement, and also serves as a suitable base for extensions. Jagtenberg and colleagues demonstrated the practical relevance of this heuristic by implementing a decision support tool in EMS region Flevoland.


Jagtenberg also introduces several models to improve the fairness in ambulance logistics. Most models in ambulance planning maximize the number of people served, regardless of where they are living. This approach benefits people living in the cities, at the expense of people living in remote areas.  Rather than simply maximizing the number of people served, she considers the distribution over the different areas where people live. To that end, ambulance optimization models from a social welfare perspective are applied.

Date: Tue, 28/02/2017 - 13:45 - 16:30

Location: Aula of the VU University, Boelelaan 1105 in Amsterdam

Promotors: prof.dr. R.D. van der Mei, prof.dr. S. Bhulai

Thesis: “Efficiency and Fairness in Ambulance Planning”