IntroductionThis paper is a review of current research and applications regarding the environmental impacts of urban sprawl. The motivation for this review is, first, the increased popular attention given to undesirable aspects of urban development, primarily in suburban areas, referred to as`sprawl'. Recently, voters in many areas have attempted to pass measures to limit the rate of development in suburban areas and to preserve green space (USHUD, 1999). Reports by nonprofit organizations such as The Sierra Club (1999) have highlighted negative impacts of sprawl such as increased traffic congestion and air pollution. Popular research by authors such as Orfield (1997) has drawn attention to the negative political and fiscal impacts of suburban sprawl, not just in the areas that are experiencing sprawl but also in the inner cities and inner-ring suburbs that are losing population to farther-out suburban areas. The second motivation for this review is the increased quantity and quality of academic research that has attempted to quantify sprawl and to assess impacts of alternative development paths. Although researchers have done valuable work in designing tools to visualize alternative development paths and to design models that incorporate current knowledge of urban growth dynamics and environmental change, more work needs to be done to unite disparate research areas related to sprawl.There is no common agreement either on the defining characteristics and impacts of urban sprawl or on the ultimate desirability or undesirability of urban sprawl. Thus, the scope of this paper will be limited to specific environmental impacts, desirable or not, of development strategies or to outcomes that may be classified as`sprawl', as distinguished from normal urban, suburban, and exurban development. In addition, the scholarly literature used to frame the discussion of sprawl will focus on the fields of land-use planning, transportation planning, urban planning, economics, landscape architecture, geography, and other related areas.My goal is to define urban sprawl and, specifically, the environmental impacts of sprawl in a consistent way and to identify and classify models and decisionmaking methodologies associated with the environmental impacts of sprawl through a survey of the academic and practitioner literature. I will also identify areas associated with