Spring 2009 Seminar Series

DATE: February 26th
LOCATION: E51-376
TIME: 4:15pm
Reception immediately following in the ORC ConferenceRoom, E40-106

SPEAKER:
Shane G. Henderson

TITLE
Ambulance Location and Relocation

ABSTRACT
Ambulance service providers all over the world are struggling to maintain service levels, as measured by response times to calls, in the face of increasing traffic congestion, increasing call volumes, and budget pressure. As a consequence, they are looking, more than ever, to provide a good match between supply and demand of ambulances. The ambulance location problem is that of determining how many ambulances to operate from each of a predefined set of bases. We first review a simple model that sheds light on this question: One should not allocate ambulances to bases in proportion to demand.

 

The optimal (static) allocation of ambulances to bases is important, but it ignores the option of dynamically moving ambulances in real time to attempt to "fill holes," which is also known as relocation, move up, and system-status management. We discuss some existing methods for relocation, as well as a new method based on approximate dynamic programming (ADP). Computational results for Edmonton (Canada), and one other city show that ADP can work well, but a successful implementation requires a mix of queueing-systems knowledge and intuition.

 

Joint work with Matt Maxwell, Mateo Restrepo and Huseyin Topaloglu