Operational Improvements at Traffic Circles: Final Report

US Transportation Collection2008PDFTech ReportOzbay, KaanBartin, BekirRathi, NehaList, GeorgeDemers, AlixandraWojtowicz, JeffreyRutgers UniversityRensselaer Polytechnic Institute. Center for Infrastructure and Transportation StudiesNew Jersey. Dept. of Transportation. Division of Research and TechnologyUnited States. Federal Highway AdministrationNew Jersey. Dept. of TransportationNew JerseyTraffic modelsTraffic circlesMathematical modelsSafetyFHWA-NJ-2008-012Final report.This study deals with the development of a credible and valid simulation model of the Collingwood, Brooklawn, and Asbury traffic circles in New Jersey. These simulation models are used to evaluate various geometric and operational improvement alternatives. An extensive review of the available simulation packages is presented. PARAMICS microscopic simulation software was selected due to its capability of modeling and simulating complex roadway structures and driver behavior. The simulation models of these circles were developed using PARAMICS. These models were validated and calibrated using the extensive field data collected as part of this project. The specifics of the collected data, and the extraction procedure are also explained in the report. The development of the simulation models and the validation and calibration steps are presented in detail. The study observed that the efficiency of these traffic circles is directly related to the gap acceptance/rejection of vehicles at yield-controlled or stop-controlled intersections, and the interarrival time of vehicles at the approaches. Therefore, at each selected location, gap acceptance/rejection models are developed based on the extracted data. The Application Programming Interface (API) of PARAMICS is used to incorporate site specific gap acceptance/rejection models. Also, to model realistic interarrival times at the approaches, the traffic signals at the vicinity of the circles are modeled using actual signal timing parameters.133