Facility Location Problems in Urban Planning Networks

Introduction to Facility Location in Urban Planning

When it comes to urban planning, there are many issues to address. One of them involves problems with facility location. This is something that is easily overlooked, but that can cause serious issues as development of a project moves along. In order to avoid location difficulties, any person or company planning a facility of any kind in an urban area needs to take the time to carefully consider where the facility will be placed and all of the factors surrounding it (Chan & Kumaraswamy, 1996). How valuable a location is also depends on the facility being constructed there (Larson & Odoni, 1997–1999). For example, downtown would not be a good place for a landfill, but it would be perfect for a postal facility.

People often like to be able to walk to places like the post office and the courthouse, as well as local restaurants and attractions. By locating them downtown, these facilities become central — and thus more convenient — to a large number of people (Larson & Odoni, 1997–1999). Areas like landfills and recycling centers, however, should be a reasonable distance from homes and other businesses because of odors, noise, and other problems they may produce. Often, companies that create various business models do not spend enough time considering where land is situated relative to other businesses and homes (Chan & Kumaraswamy, 1996). They look at the cost of the land but do not adequately weigh the other factors of location.

Examined here are three types of problems with facility planning and location — center problems, requirements problems, and median problems. All three must be addressed for a company or individual to have the best chance of finding the right location for a new facility. Without clear consideration of all three factors, there is a distinct possibility that the facility will end up in an area that is inconvenient for the company and for the people who live and work nearby, causing problems all around (Chan & Kumaraswamy, 1996). Because of those concerns, it is important to define and address each of the three problem areas.

Three Core Facility Location Problem Types

Center Problems — These are also often called minimax problems, and they are most commonly associated with facilities that handle emergency services, such as police, fire, and ambulance. Facilities like these must be located so that they can serve the maximum number of people within the shortest distance (Larson & Odoni, 1997–1999). In other words, they have to be located at the "center" of things so that they can serve more people effectively and efficiently. Placing a fire station on one side of town instead of in the middle, for example, would be indicative of a center problem. For larger towns, there will be more than one fire station — but each should still be located as centrally as possible within the geographic boundaries of the districts it serves (Larson & Odoni, 1997–1999).

Requirements Problems — Problems with requirements arise because there are a pre-specified number of facilities required to meet certain standards in specific areas (Larson & Odoni, 1997–1999). The locations of these facilities are often decided early on, and it is up to companies and town regulators to ensure that the facilities are placed where they are supposed to be, even if another location may appear better. This is a more general concern that does not apply only to emergency services (Larson & Odoni, 1997–1999). By locating facilities in places — and quantities — that meet requirements, specific standards of performance will more easily be achieved.

Median Problems — With median problems, it is usually non-emergency services that are at issue. These types of problems are related to the number of facilities that must be located in proximity to one another so as to provide people who need the services with the right kinds of opportunities (Larson & Odoni, 1997–1999). Generally, these facilities include town halls, government agencies, and transportation hubs such as taxi services, bus stations, and train stations. People do not want to travel to the courthouse on one side of town and then be required to drive all the way across town to the police station. Having all related facilities in one centralized location makes a meaningful difference in the lives of residents, as well as in traffic flow and other urban planning considerations (Larson & Odoni, 1997–1999).

There are extensions and variations on all three kinds of problems, as well as some overlap and intermingling among them (Larson & Odoni, 1997–1999). This is very important to recognize, since it can lead to significant applications in the field of urban service. A more in-depth discussion of the issues is therefore warranted. The frameworks described here can be beneficial to anyone planning a facility in or around any type of urban area, and can also be applied in rural settings.

Network Models and Graph Theory in Urban Areas

When conducting an in-depth study of facility location problems, network models of metropolitan or urban areas are particularly convenient and helpful resources (Larson & Odoni, 1997–1999). Transportation arteries are represented as links within a given network (Frank & Frisch, 1971). Points where those arteries intersect are the nodes. Travel takes place along the nodes and links of a network and is restricted to those areas (Larson & Odoni, 1997–1999). It is also assumed that demands for services of any kind will be generated only at a specific number of points, which are designated as network nodes (Larson & Odoni, 1997–1999).

Some may feel that this finite number of service-demand points lowers the usability of the network model, but this is not really the case. As many nodes as needed can be placed along the networks, allowing for realistic and detailed models of a particular area, the people moving through it, and the services those people require (Larson & Odoni, 1997–1999). The intensity of demand for service at a particular node is weighted, so that the true value and need for it — as represented in actual society — can be accurately captured. Without this weighting, it would appear that all nodes were equal (Larson & Odoni, 1997–1999). Both research and common sense show that this is not the case, and that some nodes — representing services and/or businesses — are more heavily used than others. These nodes generate more traffic and should therefore be weighted accordingly (Larson & Odoni, 1997–1999).

Conclusion

When center, median, and requirements problems can all be solved together, it opens the door for addressing other subsets of facility location challenges — including siting facilities that people want placed as far away as possible (Larson & Odoni, 1997–1999). These often include recycling centers and landfills, as well as factories and other operations that produce significant pollution or other problematic conditions within a geographic area (Church & Garpinkel, 1978; Beltrami & Bodin, 1974). Other facilities, like recreation centers and parks, are sited using similar calculations, with the goal of ensuring they are neither too far from citizens nor placed in locations where their usefulness would be diminished (Larson & Odoni, 1997–1999). It is not always possible to place a facility exactly where it ideally should be, but the overarching goal of facility location planning is to site facilities as close as possible to their optimal positions in order to provide the most benefit to the greatest number of local citizens.

References

Beltrami, E., & Bodin, L. (1974). Networks and vehicle routing for municipal waste collection. Networks, 4(1), 65–94.

Chan, D.W.M., & Kumaraswamy, M.M. (1996). An evaluation of construction time performance in the building industry. Building and Environment, 31(6), 569–578.

Church, R.L., & Garpinkel, R.S. (1978). Locating an obnoxious facility on a network. Transportation Science, 12, 107–118.

Frank, H., & Frisch, I.T. (1971). Communication, transmission, and transportation networks. Addison-Wesley.

Golden, B.L. (1976). Large-scale vehicle routing and related combinatorial problems (Unpublished doctoral dissertation). MIT Operations Research Center.

Hakimi, S.L. (1964). Optimum locations of switching centers and the absolute centers and medians of a graph. Operations Research, 12, 450–454.

Handler, G.Y., & Mirchandani, P.B. (1979). Location on networks: Theory and algorithms. MIT Press.

Kamara, J.M., & Augenbroe, G. (2002). Knowledge management in the architecture, engineering and construction industry. Construction Innovation, 2, 53–67.

Krolak, P., Felts, W., & Nelson, J. (1972). A man-machine approach toward solving the generalized truck-dispatching problem. Transportation Science, 6, 149–170.

Larson, R.C., & Odoni, A.R. (1997–1999). Urban operations research: Chapter 6 — Applications of network models. Massachusetts Institute of Technology. http://web.mit.edu/urban_or_book/www/book/chapter6/contents6.html

Lock, D. (1996). The essentials of project management. Gower.

Mirchandani, P.B., & Odoni, A.R. (1979). Locating new passenger facilities on a transportation network. Transportation Research, 13B, 113–122.

Revelle, C., & Swain, R.W. (1970). Central facilities location. Geographical Analysis, 2(1), 30–42.

Rosenfeld, Y. (1994). Innovative construction methods. Construction Management and Economics, 12(6), 521–541.

Toregas, C., Swain, R., Revelle, C., & Bergman, L. (1971). The location of emergency service facilities. Operations Research, 19, 1363–1373.