During the last two decades, planning processes involving public facilities is increasingly more complex and
facility location models are among the indispensable decision-aid tools (Teixeira and Antunes, 2008). These models
are used to find optimal or near optimal locations for activities that service some kind of demand distributed in
space. The objective is usually to minimize or maximize certain variable(s), or conform to a pre-specified
performance standard before locating the facility (Miller and Shaw, 2001). A variant of the facility location model is
the location-allocation model which obtains the best location for a facility as well as assigns demand points to the
facility based on criteria such as distance, time, and cost. Such location-allocation model provides a framework for
investigating service coverage, analyzing and comparing location based decisions, and generating more efficient
alternatives (Rahman and Smith, 2000).