Delay analysis at a signalized T intersection

Traffic signal delay is one of the major problem people face in urban areas. An effective traffic signal timing and phasing arrangement has to be implemented to optimize the delay for all vehicle moments through the junction. Apart from signal timing arrangement, other factors such as geometry also influence the delay at an intersection. The aim of the research is to analyze and find the parameters influencing the delay at a signalized intersection and get an optimize condition which can reduce the delay at the selected junction. For the case study Katubedda Junction has been selected. The traffic simulation software vissim has been used for the analysis. Calibration of the vissim model to Sri Lankan conditions was achieved by changing the driving behavior parameters of the software model and matching the propagated queue length in model with actual queue length. Some of the causes of the delay were identified and those geometrical and signal timing changes were categorized into three different alternatives. All three alternatives were modeled in the software with the existing condition as the base case. The results show that changes in signal timing arrangement and changes in the geometrical arrangement has to be done to reduce the delay at the selected location