New pavement performance models developed for the national road network in Uganda

This study developed pavement performance models for Uganda's road network using the modified Markov Chain Model (MCM) and analyzed the effect of initial Visual Condition Index (VCI) on pavement deterioration. The modified MCM used the time-deterioration superposition principle to generate pavement performance master curves. Four predictive models – the logistic, Richards, pavement behaviour equation, and Weibull models – were evaluated for their effectiveness in describing the master curves. The results revealed varying deterioration rates based on the initial VCI and traffic levels. For heavy and intermediate traffic pavements in very good, good, and fair condition, deterioration rates decreased with lower initial VCI while pavements in poor and very poor condition, deterioration rates increased as initial VCI decreased. For light traffic pavements, deterioration rate generally increased with decreasing initial VCI. Among the evaluated models, the Weibull model consistently provided the best fit and is recommended for use in the Ugandan Pavement Mangement System.