Applicability of various capacity models for single-lane Roundabouts in izmir, Turkey

Although many traffic circles have been designed in Turkey, in recent years few studies have been made on the capacity and performance of roundabouts. In practice, two major problems at intersections need to be solved: traffic accidents and limited intersection capacity. With this in mind, the applicability of various capacity models for single-lane roundabouts to six selected roundabouts in Izmir, Turkey, is discussed. The results show that the HCM2000 procedure can be used as an effective too for an initial prediction of single-lane roundabout capacity if the lower and upper boundary limits are calibrated. But, since the research was conducted with limited data, the accuracy of the results should be tested with more data sets. Further studies should be conducted to develop a more reliable capacity and performance analysis procedure, especially for Turkey.