Traffic control strategies of signalized circular intersections are analyzed in this article after a brief overview of traffic lights in roundabouts. A detailed description was made on the ‘direct’ mode of operation of the Hungarian regulation describing three types of control program. Finally a comparison of traffic performance is given based on the main geometric features and parameters of the signal programs with a description of the signal plan structure. The PTV Vissim environment was used to examine and evaluate the performance of each combination through the average delay per vehicle resulting proposals for the application as well as for further studies in subject.
Authors:Szabolcs Barna, Attila Kollár and Gábor Schuchmann
Passenger car unit is an important comparison factor that helps the traffic engineer to describe the impact of heterogeneous traffic flows on the traffic performance of the infrastructure elements, compared to homogenous passenger car flows. The purpose of this study is to determine the passenger car unit value of certain vehicle types (e.g. buses, trucks) in signalized circular intersections. The values defined by the Hungarian standards are based on the weight and type of the vehicles, so it is important to know how these parameters of the vehicles influence the traffic conditions at this unique type of road junction, to be able to conduct a correct capacity calculation. PTV Vissim microscopic simulation program was used to model different traffic volumes and compositions getting by the recommended passenger car unit values for the application, and a proposal for further studies in subject.