Dai, Yizhen (2015-12). Assessment of the Operational Impacts of Comprehensive Waiting Areas at Signalized Intersections. Master's Thesis.
Urban intersections are becoming increasingly congested when limited land use for transportation cannot fully serve the growing traffic demand in metropolitan areas. A new concept--Comprehensive Waiting Areas (CWAs) -- has been proposed recently to increase the capacity of signalized intersections without flaring up the approaches. CWAs use part of approach lanes as left-turn and through waiting areas to fully utilize space resources. The practice of implementing CWAs in Guangzhou and Shanghai, China, shows its superiority in decreasing approach delay under heavy traffic demand. Despite the promising future of CWAs, there are few studies into CWA design and operation. To assess the operational performance of CWAs at intersections, a local intersection was selected in this study for CWA design adoption. Key issues concerning CWA length design and signal timing plans are then discussed, along with comparisons between operation of intersections, with and without CWAs. PTV VISSIM is utilized to simulate intersections with and without CWAs. The results confirm the potential benefits of CWAs and show CWAs work best in heavy traffic demand, especially when the turning percentage is high. However, the benefits of CWAs may be limited when traffic demand is significantly imbalanced.