Thesis (M.S., Civil Engineering) | While isolated intersections in small to medium sized cities do not typically experience the high traffic volumes of heavily populated urban areas, the amount of tailpipe emissions and gas consumed are significant. The purpose of this thesis is to provide practitioners with a guideline for reducing emissions and fuel consumption at fully-actuated isolated intersections, considering vehicle volume levels expected in small urban areas. This study applies an industry-standard engine performance model to verify prior research findings that the number of stops is an adequate measure of effectiveness to reduce the environmental impact of traffic operations at isolated intersections. Microscopic traffic simulation was used to investigate a variety of actuated timing settings, using multiple vehicle detection systems, with the goal of identifying strategies that governing agencies might use to better time isolated intersections with keeping environmental impacts in mind. The results consistently show that the passage time setting carries the most weight, especially on the minor approaches, in limiting environmentally harmful by-products of traffic. The number of stops on the major approaches was less sensitive to the passage time setting on the major approaches, but better performance was observed when a higher value of passage time was used. The minimum green setting was found to have an impact at low vehicle volumes only. Practitioners may use the guidelines presented in this paper to adequately time actuated control parameters to reduce the environmental impact of traffic at isolated intersections.