In recent years there has been increasing recognition of the importance of studying land and the role human beings play in shaping the land. Much of the inquiry has focused on patterns of land-use change. Theories addressing land-use change have been offered by such diverse fields as economics, urban and regional science, sociology, social physics, environmental history, environmental psychology, biology, ecology, and geography (Briassoulis, 2000). Each discipline has offered useful insights into the processes of land-use change, but to date there is no single unifying theory that integrates the important insights from all the relevant disciplines. In particular, when reviewing the literature a gap in land-use change theory and modeling becomes evident. Many developers of land-use change models acknowledge the importance of political institutional factors. Hubacek and Vazques (2002), for example, note: "Institutional factors set the frame influencing (economic) behavior...Public regulations, such as community plans, zoning ordinances, rent controls, subdivision regulations, building codes, and laws pertaining to mortgage finance shape the development and use of real property". Yet despite the general acknowledgement that institutions play an integral role in the land-use change process, and despite the existence of numerous empirical investigations into the impacts of government policy on land-use, a theoretical framework for analyzing the relationships among various political institutional factors and land-use change has been lacking (see for example Briassoulis, 2000 or National Center for Geographic Information and Analysis, 2001).
The primary purpose of this article is to propose a conceptual model of land-use change that includes a framework for incorporating political institutional factors in the land-use change process. The basic landuse change model developed herein draws extensively from existing theories and models of land-use change, and the political institutional framework is informed by public choice theory. The secondary purpose of the article is to use the conceptual model to explain some empirical results researchers have found regarding the relationship between the political institutional environment of a given locality and the prevalence of sprawl. Extensions of the conceptual model, including testable hypotheses, are also proposed.
2. SPRAWL: DEFINITION AND MEASUREMENT
An analysis of the political institutional dimensions of land-use change would be incomplete without a discussion of sprawl, as it represents the most critical land-use issue in many regions. There is no single accepted definition of sprawl. Burchell et al. (2005) characterize sprawl as "a type of development with...(1) unlimited outward extension into undeveloped areas, (2) low density, and (3) leapfrog development". Burchell et al. (2005) further note that "sprawl is not simply development at less-thanmaximum density; rather, it refers to development at a low relative density...". Kolankiewicz and Beck (2001) define sprawl as "the rural acres lost as an Urbanized Area spreads outward over a period of time," an Urbanized Area consisting of a central city and its contiguous suburbs. Fulton et al. (2001) distinguish a sprawling area from a "densifying" area as follows: "If land is being consumed at a faster rate than population growth, then [the area] can be characterized as 'sprawling.' If population is growing more rapidly than land is being consumed for urbanization then [an area] can be characterized as 'densifying'".
Even though sprawl is not a precise term, several useful measures have been advanced. Sprawl indices have been developed by such diverse organizations as the Rutgers University Center for Urban Policy Research, Smart Growth America, and USA Today (Burchell et al., 2005). Each index has advantages and limitations, a discussion of which is beyond the scope of this article. …