Although environmental justice research has typically focused on locations of industrial toxic releases or waste sites, recent developments in GIS and environmental modeling provide a foundation for developing measures designed to evaluate the consequences of transportation system changes. In this paper, we develop and demonstrate a workable GIS-based approach that can be used to assess the impacts of a transportation system change on minorites and low-income residents. We focus specifically on two adverse affects: vehicle-generated air pollution and noise. The buffer analysis capabilities of GIS provide a preliminary assessment of environmental justice. We integrate existing environmental pollution models with GIS software to identify the specific locations where noise and air pollution standards could be violated because of the proposed system change. A comparison of the geographic boundaries of these areas with the racial and economic characteristics of the underlying population obtained from block level census data provides a basis for evaluating disproportionate impacts. An existing urban arterial in Waterloo, Iowa, is used to illustrate the methods developed in this research.