Calculation model for capacity of self-organized roundabouts for mixed traffic flow in Chinese cities

With urbanization and road network expansion, once core circular intersections now face inefficiencies amid surging traffic. Chinese cities thus reconstruct them into signal-controlled crossings or demolish them, but lack clear decision criteria and evaluation systems, hampering scientific choices. Under China’s unique mixed traffic, roundabouts differ greatly from those in the U.S. Highway Capacity Manual (HCM) or European manuals in design, control, and capacity models. Yet China has no complete technical specs here, making foreign-model-based capacity calculations unreflective of its reality. To solve this, this study develops roundabout capacity models/methods fitting China’s traffic. Comparative analysis shows its theoretical capacity is closer to China’s reality; calculation and simulation verify its accuracy. It optimizes roundabout design, boosts capacity, and provides scientific/technical support for easing congestion and improving transport efficiency.