Research on Traffic Circle Capacity

Traffic circle is an important type of non-signalized intersection, and there is an extensive use of it. In order to improve traffic capacity and safety, different traffic circles adopt different traffic priority, for example, vehicle in-circle precedence method and the vehicle entry-precedence method. This paper studies the applicability of different traffic priority based on the traffic circle capacity. Assume that the time headway within the circle obeys Erlang distribution, and by using the gap-acceptance theory, the paper suggests the calculation formula of the saturation flow of the traffic circle. Based on the model solution, a critical value can be got to distinguish the applicability of different traffic priority. Therefore, the solution could help relevant departments make decision.