Papyrus Press Advance Researches in Civil Engineering 2645-7229 6 4 2024 12 01 Integrated Congestion Analysis and Simulation-Based Improvement of the Al-Faris Al-Arabi Roundabout Using PTV VISSIM 17 30 250669 10.30469/arce.2025.568408.1091 EN Sepehr Saedi Department of Civil Engineering, Engineering Faculty, Altinbas University, Istanbul Turkey 0000-0002-5255-2099 Mina Mohammad Department of Civil Engineering, Engineering faculty, Altinbas University, Istanbul, Turkey Journal Article 2025 12 24 Rapid growth in private-vehicle use and limited upgrades to traffic infrastructure have led to chronic congestion at key intersections in Baghdad. The Al-Faris Al-Arabi Roundabout is a critical bottleneck, with long queues and unstable circulating flow during peak hours. This study applies an integrated approach that combines field traffic counts, a commuter-perception survey, and microscopic simulation using PTV VISSIM to assess existing conditions and test improvements. Baseline results show average delays of about 80 s/veh, queues exceeding 150 m, and Level of Service (LOS) D, while more than 70% of surveyed users report daily delays above 20 minutes and noticeable stress and health impacts. Two mitigation strategies are evaluated: a flyover connecting Al-Mansour and Al-Zaytoun Streets, and adaptive signal control at the roundabout entries. The flyover reduces delays by roughly 19% and queues by 38%, whereas adaptive signal control achieves delay reductions of about 14.5% and queue reductions near 30%, with lower cost and faster implementation. The findings highlight the value of combining field data, user perceptions, and simulation to support congestion-mitigation decisions in rapidly developing cities like Baghdad. https://www.arce.ir/article_250669_3017ba7256092d7595a77e13dbac2213.pdf