This paper discusses traffic flow dynamics, including free flow speed, speed drop threshold speed, and free and congested traffic conditions, in the Keffi-Abuja motorway, Masaka City, Nigeria. It seeks to generate insights for congestion management infrastructure optimization, and environmental impact assessment. Data was collected using a vehicle-speed recoding camera, in weekdays of January to February and August 2023, to capture the speed and volume. Free flow speed, speed drop, threshold speed was calculated to be around 51 km/h, 12–20 km/h, 30–39 km/h respectively. This threshold speed was used to estimate congestion periods as 7:01 AM–10:00 AM, 12:01 AM–1:00 PM. in January and February, as well as 7:01 AM–8:00 AM, 10:01 AM–11:00 AM, 12:01PM to 3:00PM for August. These results illustrated specific time periods with high probability of traffic congestion, associated with commuter patterns and increasing congestion on this road. The speed reduction index method validates the traffic states observed in January, February and August analysis. Such a finding shall lead to congestion management strategies, such as adjustments to the traffic signals and alternative transportation modes, which could reduce congestion. The study, while providing an analytical framework regarding traffic flow dynamics and congestion patterns, acknowledges limitations in terms of generalizability due to the exclusion of non-recurring conditions, driver behavior, and emerging technologies. This research contributes valuable insights into traffic flow dynamics and congestion management, infrastructure optimization, and environmental sustainability.