Operational and Emission Analyses of Roundabouts Under Varied Vehicle and Pedestrian Demands

017016152018Year 25 Final ReportPDFTech ReportUMAR25-24DTRT13-G-UTC31Environmental impactsAir pollutionCellular automataExhaust gasesMicrosimulationRoundaboutsPedestrian trafficSignalized intersectionsTraffic delaysTravel demandOperational impactsOperations and Traffic ManagementUnited StatesNew England University Transportation CenterChristofa, EleniKnodler, Michael A.University of Massachusetts at AmherstNew England University Transportation CenterUniversity Transportation Centers Program (U.S.)United States. Department of Transportation. University Transportation Centers (UTC) ProgramUS Transportation CollectionRoundabouts are becoming more and more common as an alternative to signalized intersections throughout the United States. The primary reason for an increased interest in roundabout construction has been their safety advantages compared to signalized intersections due to the reduced number of conflict points and lower vehicle speeds (1). As a result of the increasing popularity of roundabouts, several research efforts have evaluated their performance in terms of operations and safety. However, only a few recent studies have focused on the environmental performance of roundabouts and those have not resulted in consistent conclusions. In addition, most of the studies have focused on the effect of car demand on emissions and there has been less attention to the pedestrian crossing impacts on vehicles' stops and emissions. The goal of the proposed research is to conduct a comparative evaluation of the impact of vehicle and pedestrian demand on the operational and environmental performance at roundabouts and signalized intersections.88