Determination of capacity at two-way stop-controlled urban intersections

Capacity analysis at Two-Way Stop-Controlled (TWSC) intersections depends on a clear description and understanding of the interaction of drivers on the minor or stop-controlled approach with drivers on the major street. As to capacities at TWSC urban intersections affected significantly by signalized intersections, an appropriate model should include the ability to represent traffic interactions in the gap acceptance process, platoon dispersion qualities, and signalized intersection control systems. Based on the field investigation and observation data at several typical TWSC intersections, gap features of major traffic streams are analyzed at TWSC intersections affected by upstream signalized intersections. Furthermore, both gap acceptance theory and motorcade analysis method are utilized to analyze the minor stream capacities at TWSC intersections. As a result, a methodology for determining the capacities at TWSC intersections is presented under one-way gap and two-way gap conditions and a computing program is designed and programmed. At last, an empirical study is given and the computing results calculated by Highway Capacity Manual (HCM2000) and the methodology proposed in the paper are compared that prove the effectiveness of the methodology. In conclusion, the methodology provides a quite valuable reference for determining the capacities at TWSC urban intersections.