The study aims to analyze, evaluate and improve of the traffic flow conditions on six roundabouts located on arterial Zahran Street in Amman area. The traffic flow and geometric conditions were analyzed at six selected roundabouts for the three periods of times, existing condition (year 2017), short-term condition (year 2022) and mid-term condition (year 2027). Highway Capacity Manual (HCM2010) and Highway Capacity Software (HCS2010) were used to analyze and evaluate the data collection for the three periods of times. The results of analysis shows that the output results of (HCS-2010) indicates LOS-F for all selected roundabouts on all period of times, which represents high congestions with breakdown traffic flow condition. SIDRA-7 software was used to improve the traffic and geometric conditions on each selected roundabouts. The output results of SIDRA-7 software shows a significant improvement in terms of level of service (LOS), total delays, fuel consumption and Co?. The study recommend to implement the improvement geometric conditions, installation of metering traffic signals, or constructing grade separation (overpass or underpass) for short-term and mid-term periods. Finally, the study proposed a future research that would be comprehensive for the impact of pedestrians on traffic congestion and traffic safety on these roundabouts. Keywords: Traffic Congestion, Roundabout Improvements, Sidra-7 Software, HCS-2010 Software, Highway Capacity Manual (HCM-2010), Active Traffic Management (ATM).