Analysis of Traffic Congestion Patterns and Causes in Onitsha Commercial Hub, Anambra State

Onitsha, one of West Africa's largest inland markets located on the eastern bank of the Niger River in Anambra State, experiences severe and chronic traffic congestion that imposes substantial economic costs on traders, transporters, and commuters across the South East geopolitical zone. This study analyses the spatial and temporal patterns of traffic congestion in Onitsha, examining causal factors including land use configuration, truck volume, market day surges, and infrastructure bottlenecks. Traffic volume counts and speed measurements were conducted at 12 intersections and along 8 major road corridors during morning peak, afternoon peak, evening peak, and off-peak periods over a four-week survey period in 2023. GIS mapping of congestion severity using vehicle density and average travel speed as proxy indicators was performed to generate a congestion heat map for the study area. Structured interviews with 200 traders, truck operators, and transport union officials supplemented the traffic count data with qualitative insights on operational impacts. Results identify the Main Market roundabout, Ochanja bridge approach, and Upper Iweka Road interchange as the three most severely congested nodes in Onitsha's road network, consistently recording level-of-service ratings below acceptable thresholds. Heavy goods vehicle movements constitute 38 percent of total traffic volume, well above typical proportions for urban roads. Recommendations include truck holding areas outside the central market zone, timed delivery restrictions, and a ring road bypass to divert through-traffic. Keywords: traffic congestion, Onitsha, market access, transport planning, South East Nigeria.