Evaluation of Al-Zahara Roundabout in Al-Najaf City Using Simulation Model and Selecting the Optimum Alternative

Nowadays, most of urban areas suffer from traffic congestion. This congestion attributed to the existing of conflicting movements at intersections, merging, roundabouts, etc. In this study, a traffic congestion problem results from roundabouts have been investigated. Although roundabouts are safer from intersections because of less conflict points, roundabouts may have less capacity than corresponding intersections. Several roundabouts were built in Iraq in the last decade as a new design to improve traffic operations. However, most of these roundabouts suffer from high congestions. Therefore this study has focused on the evaluation of AL-Zahara roundabout as a sample from other roundabouts in the city. A simulation model called S-Paramics has been used to evaluate the performance of these roundabouts. Then, field data have been collected for more than 10hours. A video camera has been installed over a multi-story building in order to capture field data from Al-Zahraa Roundabout. This field data has been used to calibrate the simulation model (S-Paramics). After calibrating and validating the simulation model, the developed simulation model has been adopted to find the suitable solution to mitigate traffic congestion using different scenarios.