Estimating response times for Insurance Services Office (ISO) accreditation


Every three years Fire Department protection is evaluated by the
Insurance Services Office (ISO). Insurance companies use the ISO ratings
to help set property insurance premiums for local government
communities. One of the items evaluated by ISO is the five minute
response time from stations. Previously the response time areas were
created by using response time locations from CAD to select properties.
This was a good process, but it was time intensive as everything was
manually extracted and selected.

After watching a Geographic Information System (GIS) Consortium
webinar about the ESRI Network Analyst Extension, the Village of
Mundelein Fire Department asked the GIS Office about the feasibility of
creating five minute response areas using routes based on a street
network. The GIS Office enhanced an existing street network by adding
speed limits to help better simulate how a vehicle might respond during
an actual incident response. They then calculated a time, or cost, for
a vehicle to traverse each street network segment. Using the
calculated routes, a five minute time area from both fire stations was
created. A second map showing five minute response times into Mundelein
from neighboring fire stations was also created. This map displays
coverage areas not included in a five minute response area from a
Mundelein fire station.

Using the ESRI Network Analyst Extension, the GIS Office quickly
created a route that could be used to create fire station response
areas. This saved the Fire Department many hours of manual labor.
Furthermore, now that a response time layer has been created, it can be
used in future projects such as inspection routing or even future ISO