The issue of traffic congestion in Phnom Penh, exacerbated by rapid population growth and construction of flyovers, underscores the need for effective traffic management strategies. In particular, efforts to mitigating congestion during flyover construction, is equally critical for ensuring smoother traffic flow and minimizing disruptions for commuters. This study proposed and evaluated several alternative solutions to minimize traffic congestion during the flyover construction period at busy intersection (i.e., Intersection 2004) in Phnom Penh. Traffic and related data were collected in October 2023 and a micro traffic simulation software was used to analyze traffic data and to evaluate alternative solutions. Results showed substantial reduction in the traffic congestion during flyover construction at Intersection 2004, lowering overall queue length by 30% to 40% and also improving vehicle travel time, compared with the common practices of flyover construction. The findings provide insights into urban traffic management planning, thus help optimizing traffic congestion, enhancing road safety, and improving overall commuter experience during construction process of major intersections in city.