Indian River County Impact Fee Study Final Report - irccdd.com

activities For other facilities such as emergency medical and rescue, it is difficult to
allocate demand to land uses when many of the calls are related to crashes.
The traditional method for estimating the current and future demand for certain facilities
is to use the population as the basis. For example, some states have established a
statewide minimum standard of 0.3 square feet of library space per capita based on the
population of communities meeting minimum thresholds. Yet, communities with high
volumes of nonresidents who use library services may need more than 0.3 square feet per
resident to effectively meet this standard. In the case of police, fire, and emergency
medical facilities, the higher the nonresident daytime population, the greater the need is
for service relative to the resident population. Moreover, it is not enough to simply add
resident population to the number of employees, since the service-demand characteristics
of employees can vary considerably by type of industry. Using unweighted population
and employment data to estimate facility needs may result in substantial error.
For many facilities, there is a convenient way to rationally attribute demand by land use
and to estimate aggregate demand for a community. This method is called "functional
population." Functional population is the equivalent number of people occupying space
within a community on a 24-hours-per-day, 7-days-per-week basis for public facilities
providing around-the-clock services, such as police and fire/EMS services (or alternative
time period such as an 11-hours-per-day, 5-days-per-week basis for public buildings,
which are open on the average only a total of 55 hours per week).
A person living and working in the community will have a functional population
coefficient of 1.0. A person living in the community but working elsewhere may spend
only 16 hours per day in the community on weekdays and 24 hours per day on weekends
for a functional population coefficient of 0.76 (128-hour presence divided by 168 hours
in one week). A person commuting into the community to work five days per week
would have a functional population coefficient of 0.24 (40-hour presence divided by 168
hours in one week). Similarly, a person traveling into the community to shop at stores,
perhaps averaging 8 hours per week, would have a functional population coefficient of
0.05.
Functional population thus, is designed to capture the presence of all people within the
community, whether residents, workers, or visitors, to arrive at a total estimate of
effective population needing to be served. Functional population measures are important
to gauge the demand for facilities serving the community 24 hours per day, 7 days per
week for services such as police, fire, and emergency medical services, or 11 hours per
day, 5 days per week for services such as public building services.
This form of adjusting population to help measure real facility needs replaces the popular
approach of merely weighting residents two-thirds and workers one-third (Nelson and
Nicholas 1992). By estimating the functional population per unit of land use across all
major land uses in a community, an estimate of the demand for certain facilities and
services in the present and in a future year can be calculated. The following paragraphs
explain how functional population is calculated.
Tindale-Oliver & Associates, Inc.
Indian River County
May 2005 II-7 Impact Fee Study