Analysis of Traffic Congestion Patterns and Causes at Major Intersections in Lagos Island

Traffic congestion at major intersections on Lagos Island, South West Nigeria, imposes significant economic, social, and environmental costs on one of Africa's most commercially active urban areas. This study analyses congestion patterns, peak-hour traffic volumes, and primary causative factors at five major intersections on Lagos Island including Marina, Broad Street and Custom, Balogun, and Carter Bridge approaches. Peak-hour traffic counts were conducted over two-week periods at each location, with classified vehicle counts distinguishing cars, minibuses, trucks, motorcycles, and tricycles. Intersection geometry and signal timing were recorded, and delay analysis was performed using the Highway Capacity Manual methodology. Driver interviews and observations at junction approaches provided qualitative data on behaviour patterns. Results reveal volume-to-capacity ratios above 1.2 at all five intersections during morning peak periods (7:00 to 9:00 AM), indicating severe congestion. Mean delay per vehicle ranges from 68 to 124 seconds, placing all intersections at Level of Service F. Non-motorised traffic conflict with vehicle flow at Balogun intersection is identified as a contributing factor to reduced capacity. Signal timing is suboptimal at three locations, with green times not responsive to actual demand. The study recommends adaptive traffic signal control systems, motorcycle lane separation at the highest-conflict intersections, and a dedicated goods vehicle delivery time window to reduce peak-hour heavy vehicle presence on Lagos Island.

Keywords: traffic congestion, intersection analysis, Level of Service, Lagos Island, traffic management