The Road Effect Zone (REZ) was described in Richard Forman's seminal book "Road Ecology" as the area affected by roads and traffic. We developed a detailed conceptual model of the Road Effect Zone based on an extensive literature review. We then developed a simple GIS extension as a pilot of a REZ model in GIS. Finally, we developed a high-resolution REZ model for traffic noise propagation and effects analysis. This project was supported by federal funding through the University Transportation Centers.