Fire Stations Quickest Response Areas

Located just south of Paris, France, Essonne County covers 710 square miles and contains a heavily industrialized northern region populated with more than a million residents. With an ever-growing number of emergency calls, the Essonne County Fire and Rescue Service (SDIS 91) has 52 fire stations responding to more than 90,000 emergency actions each year. In 2006, SDIS 91 upgraded its entire Emergency Management System, one part of it being the computer-aided dispatch (CAD) system. The 15-year-old text-based software was replaced with a GIS-based system synchronized with an ArcSDE spatial database maintained by SDIS 91.

One of the main goals of using a more sophisticated CAD system was to improve the emergency response time of fire station personnel with location-based dispatching of available fire station emergency vehicles. In 2005, an ArcView Avenue script was developed to compute the three closest fire stations for every middle point of the road network’s polyline in both urban and rural sample areas of the county. To improve the system and achieve more realistic results, the legal speed limit attribute in the NAVTEQ Navstreets database was dropped in favor of an average speed limit attribute. This attribute had values based on several criteria such as traffic volume, number of lanes, road category, and local ground knowledge. After extensive testing, validated calculations were carried out on 60,000 polyline road networks to produce a list of the 40 closest fire stations for each and every polyline. These lists were implemented into the CAD system as a static reference for on-the-fly calculations that take into account temporary obstacles (e.g., road closures, construction). After locating an incident, a dispatcher is able to quickly transmit emergency orders to the closest fire stations determined by the system.

Courtesy of Essonne County Fire and Rescue Service (SDIS 91).