In the LEAM implementation process, the LUC model evolves as an iterative process of data collection, model building, dialogue, visualization, and general presentation and access. Local planners, policy makers and stakeholders (convened by local planning entities and identified broadly as possible) provide feedback and input about the local salience and value of any given simulation. This feedback is gathered regularly and begins at project inception. It is used to more effectively capture the local condition, to provide a better local version of the tool and to inform local stakeholders about the tool and its uses. This form of use-driven
modeling and system development, which takes place in very public forums, is what most distinguishes the LEAM approach [22
]. The feedback and local dialogue elements are critical in the creation of useful PSS tools especially in terms of overcoming market distortions. Constant internal and external review and interaction are critical to informing both the modeler and the local stakeholders of modeled changes, improvements and scenario outcomes. Presenting this use-driven approach in publically accessible PSS visualization portals helps provide another layer of feedback and interaction. Consensus building is performed and achieved using typical planning procedures (see [29
] for a more detailed discussion on use-based modeling and consensus building).
In applying this use-based model process we have found that LEAM can influence decision-making through various pathways [29
]. In the following, we describe some specific pathways and their effect on the plan-making process in past LEAM applications. The three cases presented below: Peoria, IL, St. Louis, MO, and McHenry County, IL represent three ways in which the LEAM PSS has made significant impacts on the practice of planning. These include: counteracting distortions, facilitating dialogue, and integrated plan making for challenging the status quo.
4.1. Counteracting Distortions in Peoria, IL
Planning decisions take place over extremely long periods of time—sometimes involving different generations, over large distances. This raises questions of inter-generational and geographic equity. As noted previously, this is compounded by the fact that planning decisions have complicated spatial interactions and environmental impacts that are often secondary, or even tertiary. Environmental costs may accrue in one form, to one generation, in one part of the geography (community, state, nation, world); while the benefits accrue in a different form, for a different generation, in another part. Delivering objective, unbiased and apolitical information can help counteract these types of phenomena that can emerge in typical public planning processes [38
Many of these issues are the result of an under-estimation of environmental impacts that are sometimes the result of information distortions. Information distortions are usually the product of local knowledge that is deeply situated in the web of accepted norms, meanings, and beliefs. If incorrect (distortions of actual causal relationships), their locally embedded nature makes information distortions difficult to overcome with traditional planning communication processes [39
]. If left uncorrected, they can lead to problematic conclusions in public discussions. One example can be seen in local and personal discounting discussed above.
In our work, we argue that providing an ability to objectively test and evaluate current and future conditions can be a powerful tool for counteracting potential local distortions and poorly considered discounting that leads to costly future consequences. In an early LEAM application in Peoria, IL we helped provide those objective arguments for local and regional planners in a simple example.
In the early 2000s, the three counties surrounding Peoria, Illinois (Woodford, Tazwell, and Peoria) were witnessing significant conversion of very fertile and productive agricultural land to residential and commercial land-use. There was a distinct sense of unease about this trend, although there was no specific analytical proof for its existence. Woodford County in particular, was concerned about its agricultural heritage. The county outlined several strategies for preserving agricultural land. One particular strategy required a change in the county zoning ordinance that would require 40-acre minimum lot size on current agricultural lands. At roughly the same time in a regional planning exercise, a number of simulations of future land-use change were being run for the tri-county region and reviewed and critiqued in public workshops [31
]. These simulations established the extent and spatial distribution of future growth in a business-as-usual scenario described through maps and depictions of the impacts of this growth. Other scenarios explored included higher and lower growth rates and various public investments and policy ideas, including the proposed ordinance change in Woodford County. Figure 1
shows expected land-use outcomes in a ‘business-as-usual’ scenario. After our simulation, we used the land cover data provided by the county’s planning board to assess loss of agricultural and ecological lands associated with future growth using 30-by-30-m resolution.
To discuss the simulation results, local planners held two big meetings and several smaller focused group meetings. Stakeholders involved in those public discussions included staff from Illinois Department of Natural Resources, citizens, non-government organizations (NGOs), local planners, and government entities. Public discussions on the 40-acre zoning requirement scenario revealed that the ordinance change would reduce consumption of agricultural land as intended but would also bring with it unexpected regional consequences. Compared to the business-as-usual scenario, the amount of agricultural land lost to development over thirty years with the proposed ordinance change dropped from 10,000 acres to 7000 acres. This was expected. Unexpectedly, when the proposed ordinance was included in a simulation, new development that would have been located in the agricultural area moved to environmentally sensitive bluffs along the Illinois River, resulting in the loss of 12,500 acres of forestland (Figure 1
). This revelation changed perceptions of the proposed ordinance and the ordinance was put on hold until a ravine overlay district focused on protecting the river bluffs was put in place.
Initially, any negative consequences of the proposed ordinance appear to have been discounted. Once people saw the simulations and understood the consequences of the proposed ordinance, this discount rate was substantially decreased to the point that protecting the bluffs became a higher priority.
It appears from the above case that explicating and elaborating on the future consequences of various public policy and investment choices may alter the extent to which these consequences are discounted by stakeholders in public deliberations. When future consequences are vaguely known and ill-defined, they are easily discounted. When potential consequences are represented in tangible and objective ways however, they make the familiar unfamiliar, they challenge habitual ways of thinking, and question what appears evident and taken for granted [40
]. In short, they can counteract normative distortions.
4.2. Facilitating Dialogue with the St. Louis Blueprint Model
PSSs can assist planners in convening local stakeholders to discuss and validate environmental assessment results and in the process arouse a regional
consciousness of the potential spatial and temporal spillover of environmental impacts. Geertman [41
] points out that PSS tools can enhance participatory planning processes, because “a greater degree of access to relevant information will lead to the consideration of a greater number of alternative scenarios—which in turn will result in a better informed public debate”. One project that exemplifies this idea is the application of LEAM to the two-state, eight-county region around St. Louis, Missouri (MO) [32
]. In this project, we coupled various other models with LEAM to analyze the potential impacts of the land-use change results. Two in particular were a four step transportation model (that utilized over 2200 Transportation Analysis Zones, TAZ) to calculate travel time changes for each scenario, and a regional economic input-output model (conducted on a household level) that provided demand for space and assessed economic implications.
In 2003, the East–West Gateway Coordinating Council (the Metropolitan Planning Organization and Council of Governments for the St. Louis region), began to use LEAM (in a version later called the Blueprint Model) as a platform for encouraging a regional dialogue on issues of economic development, social equity and environmental sustainability. Instead of initializing the process with a lengthy model-building exercise, the initial focus was set on quickly producing a set of simulations. This quick-start process served two purposes: to quickly begin the process of engagement and build interest; and to collect information from the local stakeholders on the state of the local condition for adapting LEAM model to fit local conditions. These early simulations were subjected to public scrutiny in workshops, meetings and other public forums. Participants in these forums provided valuable insights into the dynamics of urban LUC in the region and a direction for future modeling efforts. Conducted on an annual basis, they also provided an excellent platform for dialogue among participants.
One early critique of the preliminary LEAM simulations presented was aimed at the way in which new development was being distributed across the two sides of the Mississippi River—the Illinois on the east, the Missouri on the west. Preliminary simulations showed considerable new developments in Illinois relative to Missouri; at the same time, the central business district (CBD) is in Missouri and has historically seen the bulk of new development. These simulations utilized posted travel speeds and did not take into account the difficulty of crossing the Mississippi River from Illinois into the CBD. When congested speeds were used to measure travel time (taking into account how traffic congestion makes portions of the region more or less attractive), simulated development shifted from Illinois to Missouri. A major factor was the effects of congestion on bridges and the approaches to them (bridges represent severe choke-points with very little opportunity for alternative routing). In the regional dialogue, this outcome highlighted the critical role played by bridges in the distribution of new development across the region.
The construction of a new Mississippi River bridge had been the subject of planning studies, preliminary design and environmental impact analysis for over 20 years in the region. A concerted civic and political effort to secure earmarked federal funding was only partially successful. The resulting funding shortfall called into question the original bridge proposal and how it would be implemented. Alternatives considered included covering the shortfall with a toll and constructing less expensive alternatives such as enhancing the capacity of an existing bridge; there was no regional consensus on the way forward. Facing a stalemate on the issue, the regional planning organization, the East–West Gateway Council of Governments (EWGateway) took the lead and sought to inject an analytical basis into the regional debate. In order to do this, however, it became crucial to go beyond traditional cost-benefit analyses and to jointly simulate and analyze future transportation and land-use consequences of the different choices.
Numerous simulations were created by coupling LEAM with a regional econometric input-output model (LEAMecon) and a regional travel demand model (TransEval). The land-use, economic and transportation outcomes in the simulations, and those of a baseline ‘No-Build’ simulation, were the basis for comparisons. Aggregate differences appear to be slight: building the bridge appears to slightly increase development in Illinois (Madison and St. Clair counties), while slightly decreasing development in Missouri (St. Louis and Jefferson counties). Interestingly, imposing a toll increased land development in far northwestern Missouri (St. Charles County). Figure 2
displays differences in LUC between the Full Build and No Build simulations at a finer resolution; red cells see more growth in the Full Build simulation, green cells see more growth in the No Build simulation. The map presents a more complex set of differences and suggests that aggregating to the county level masks greater change: while building the bridge facilitates greater land development in the Illinois side of the region and takes away from development on the Missouri side of the river, there are significant differences in development at the local level.
EWGateway convened three big public meetings and tens of smaller meetings to discuss the simulation results. As might be expected, discussions around these simulations were quite intense. Outcomes appeared counter-intuitive; imposing a toll on the bridge increased total travel times in the region. Working through the complex interactions suggested a striking explanation; the toll was diverting traffic to the other bridges across the river that do not impose a toll, increasing congestion on these bridges, and increasing travel times. This explanation brought into question the wisdom of using a toll to cover the budget shortfall. There were other insights generated: patterns of land use are likely to change if additional river crossings are built, therefore cooperative land-use policies and controls must be put in place in these areas to manage these impacts. Ultimately, however, only slight differences were uncovered even though the magnitude of the investment required for each of the scenarios tested was very different. This suggests that perhaps the lowest cost alternative is preferable, but it also suggests that demand-side tactics, such as investing in a better regional jobs-housing balance, might be more cost effective.
In this case, the LEAM PSS assisted planners in convening local stakeholders to discuss and validate each bridge scenario and their potential implications. The user-based process clearly facilitated a regional dialogue and aroused a regional consciousness of the potential spatial and temporal spillover effects. The process also helped challenged conventional thinking about the fundamental needs and benefits of the proposed investment.
4.3. Planning for a Deviation from Current Developmental Path in McHenry County, IL
In the previous discussion, including environmental assessment in planning processes and decision-making informed a public dialog so that participants had a better appreciation for the future environmental consequences of their public policy and public investment choices [33
]. These planning processes however, are essentially forward looking exercises. Many similar processes that do not use PSS technologies rely heavily on projecting existing conditions into the future. They generally fail to capture changing paradigms or emergent behaviors. This often results in the continuation of existing developmental paths.
The use of PSS tools enable a broad range of multi-directional analysis that might be useful in analyzing or planning for structural change—including those needed to address a host of environmental market failures. The idea of backcasting
using PSS technologies for example, has been shown effective in sustainable development planning [43
]. Deal et al. [44
] propose that backcasting from a desirable future state using PSS tools enables planners to step outside current developmental trends to test ideas and reexamine assumptions. Where a forecast projects an image of the future based on a current situation, a backcast starts at a point in time in the future and draws a developmental path back to the current condition. This is useful for plotting a path that responds to “how do we get there” kinds of questions from future states that might not emerge from existing trends.
A LEAM application in McHenry County, IL demonstrates a PSS-led backcasting exercise that helped the county understand how a desired deviation from their current developmental path might be achieved.
McHenry County, IL defines the northwest edge of the seven counties that make up the Chicago metropolitan region. It is approximately 60 miles northwest of downtown Chicago. It has a population of 318,000. Its location and unique natural features create a quality-of-life that is attractive to many. Since 1990, the county’s population has grown 40%, averaging 2.3% growth annually. The previous land-use plan for the county was the McHenry County Land Use Plan 2010, which was compiled in 1993 and updated in 2000. However, McHenry County Regional Planning Commission (RPC) deemed this plan increasingly irrelevant and began to compile the McHenry County 2030 Comprehensive Plan in 2007 [26
In 2007, with the help of the State of Illinois Department of Natural Recourses, the LEAM Laboratory began to build a PSS for the County. The original work was designed to assess the potential future implications that urban land use changes would have on the natural resources in the County. It was soon put to use to inform the discourse and test some of potential distortions emerging from their 2030 process [45
]. The PSS development process first established a ‘reference’ or ‘business-as-usual’ scenario as a baseline for assessing the impacts of various land use policies being discussed. The reference scenario simulated LUC if current growth pattern trends continue to 2030. Other model scenarios were then compared to the reference scenario in order to understand the impact that the tested policies might have on various important county assets. LEAM was coupled with other impact models (as described above) to assess: land-use, water demand, water quality, wetlands, natural areas, agricultural uses, and groundwater protection (the list was determined by county stakeholders). Of particular interest to the County was the loss of important agricultural and ecological lands associated with future growth. These were evaluated linking LEAM to the Land Evaluation and Site Assessment (LESA) modeling framework from the Illinois Department of Agriculture [46
The McHenry County Planning board convened more than 10 public meetings made up of a range of public interests, stakeholder groups, government employees and officials, and planners. The process revealed an early, major concern with the projected population forecast for 2030 that was derived using LEAMecon. This was the bellwether issue that underlay a larger conflict on the future of the County between pro and anti-growth advocates; one group of residents hoping to continue the past development trends and environmental groups urging protection of environmentally sensitive and agricultural lands. After lengthy discussions LEAM simulated a range of potential scenarios identified by the County Planning Board (18 prime scenarios) of future land-use patterns. The RPC identified various preferred outcome scenarios [26
]. One such scenario, the Compact Contiguous Growth (CCG) composite scenario is shown in Figure 3
. The difference between the reference scenario and the CCG composite scenario is on the left. Areas in blue receive more development in the CCG composite scenario; areas in red receive more development in the Reference scenario. A notable difference is seen in the southwest portion of the County. This is due to a limit that the CCG composite scenario places on the amount of vacant land available in that part of the county. The right shows an urban growth boundary that was also considered as part of the scenario analysis.
The spatially and temporally explicit information generated by the LEAM PSS helped the McHenry County Regional Plan Commission (RPC) objectively assess the impacts of their proposed policies. For example, one scenario identified spatial locations where farmland and ecologically sensitive areas were identified as at risk [47
]. With LEAM information, the RPC could specify where to set up ecological/agriculture preservation districts to prevent a disruption of the critical areas.
The process represents a typical PSS backcasting exercise. First, a desirable outcome was established—in this case, minimizing agricultural and ecological land losses. Backcasting how to achieve this desirable outcome required an analysis of the complex interactions between a host of variables, so that many multiple model iterations were examined in order to understand exactly what this preservation meant to county stakeholders. Once these were unraveled, a coherent set of policy levers were developed for how these outcomes for the future might be achieved. In this case agriculture productivity was closely tied to the introduction of a new (and also desired) transportation investment (a new interchange conflicted with highly productive agricultural lands). The LEAM PSS provided useful spatially explicit information on where, when, and how to plan for an alternative, desirable future that was just outside current development patterns.
The LEAM PSS enabled a ‘continuous planning’ process to take shape in the county. The spatial and aspatial data created for the PSS allows the community to continuously interact with the data and models associated with the plan (a visualized interactive tool is shown in Figure 4
). It is now a living comprehensive plan where critical questions can be examined, progress on critical issues can be updated and communicated, and success or failure can be determined and re-assessed. We suggest this type of tool and process are critical for challenging existing (and unsustainable) growth and development practices and challenging the status quo.