It takes seven minutes for an ambulance to respond to an emergency call in Montreal. That, at any rate, is the norm set by Urgences-Santé for the metropolitan region. However, calculations by Université de Montréal transportation experts at the Centre de recherche sur les transports (CRT) now suggest that those ambulances could be on the scene within three-and-a-half minutes. Considering that every minute matters in a life-and-death situation, the new CRT figures are worth their weight in gold.

Computer simulations programmed at CRT repeatedly showed "virtual" vehicles reaching their goals faster than ambulances do in reality. The reason for this success is due mainly to a more efficient re-deployment of the ambulance fleet on the street. At present, vehicles are routed and parked "by hand" after leaving the garage. The dispatchers suggest the best sites to re-position off-call ambulances, based on where the vehicles are and where calls are coming from. The operation can (and must) be done quickly, but nothing is as efficient as a computerized system. The software developed at the CRT handles these complex constraints.

"It's a theoretical study," says CRT director Michel Gendreau, who co-authored the article published in the journal Parallel Computing. "But the first results from simulations are very encouraging."

Dispatching emergency vehicles has been the subject of several studies in the past, but few of these dealt with the deployment of vehicles in motion. However, this variable must be increasingly considered where ambulances are deployed by a satellite-controlled global positioning system (GPS). There's also nothing to prevent designing versions of the program for police patrol cars, electrical repair trucks, fire trucks and other emergency vehicles.

For CRT researchers, anticipating transportation problems is all in a day's work. They actually started working on the ambulance problem back in 1994. Then Urgences-Santé, which is mandated to ensure ambulance services in the Montreal area, got interested, and began supplying data and collaborating on the simulations.

Last year, a student at the Université de Valenciennes in France, Émilie Frot, began studying the special problem posed by emergency medical vehicles. Urgences-Santé has just three doctors on the day shift for the entire Montreal area - two in the evening and one late at night. The cars these doctors travel in have flashing emergency lights and the organization's colors, but they cannot transport patients. When calls come in, the doctors head for the place where their presence is required. In a postdoctoral research study, Ms. Frot has suggested a method of calculation that would allocate these vehicles more efficiently.

Researcher: Michel Gendreau
Phone: (514) 343-7435
Funding: Fonds de la recherche en santé du Québec, Natural Sciences and Engineering Research Council of Canada (NSERC)