Comparative Study of Signal Control Models for Roundabouts

Traffic signal is one of the control approaches used for roundabouts. Although many models are used for signalized roundabouts, studies involving their comparative analysis are insufficient. This study focuses on evaluating traffic signal timing approaches used for roundabouts. Different control models of roundabouts were carried out by using VISSIM software. We compared three different types of signal control methods, including the priority control, the entrance signalization, and the full signalization control approaches. A number of simulation experiments were designed. Signal timing values were calculated by using the data obtained from field observations. The new signal timing process and calculating method were proposed for the two-stage left-turn signal control. Some detailed experiments were also conducted on the Yang model and the model developed by Cakici and Murat. Some threshold values were determined in the experiments. Different intersection geometries and traffic conditions were taken into account. Very interesting and encouraging results were obtained.