Evaluation of Pothole Formation and Road Pavement Failures on Urban Roads in Enugu Metropolis

Urban road pavement failures in Enugu metropolis, South East Nigeria, have resulted in widespread pothole formation, vehicle damage, and increased road traffic accidents. This study evaluates the extent, pattern, and primary causes of pothole formation and pavement distress on selected urban roads in Enugu metropolis. A descriptive field survey approach was adopted, involving visual pavement condition assessment on twelve road sections across Enugu North and Enugu South Local Government Areas using a structured distress inventory. The Pavement Condition Index method was applied to quantify distress severity and extent. Traffic volume counts and sub-base core samples were collected from six road sections for laboratory analysis. Results indicate that fatigue cracking, longitudinal cracking, and potholes are the dominant distress types, accounting for 68 percent of recorded defects. Sub-base materials in four of six sampled sections failed to meet California Bearing Ratio requirements. Inadequate drainage is identified as the most significant contributory factor, with 75 percent of the worst-performing sections located in low-lying areas with blocked or absent side drains. Heavy commercial vehicle overloading was cited by traffic enforcement officers as a secondary but consistent contributory cause. The study concludes that a combination of drainage improvement, strict axle load enforcement, and timely pothole patching can significantly extend road service life. Recommendations include adoption of the road asset management system by the Enugu State Ministry of Works and adoption of recycled asphalt patching as a cost-effective maintenance strategy.

Keywords: pavement failure, pothole, Pavement Condition Index, road maintenance, Enugu State