Mixed traffic flow analysis on roundabouts

Data collected at four roundabouts in the suburban area of Chandigarh city are analyzed using five different methods of determining the entry capacity. The wide variation is observed in the results. The Indian model gives the highest capacity amongst all methods. However, this method is based on the capacity of weaving section which can accommodate the least traffic. Among other four methods, the UK model gave the maximum and the US model estimated the minimum capacity of an approach. The German and the Swiss models produced quite moderate results. A simple empirical method is proposed in this paper to determine the entry capacity from the flow conditions alone. The capacity values estimated by this method are quite comparable to those given by the German method.