The Use of Measured Pavement Performance Indicators and Traffic in Determining Optimum Maintenance Actions for a toll road in South Africa and Comparison with HDM-4 Predictions

The Bela-Bela/Polokwane toll road on National Route 1 was the first Build, Operate and Transfer (BOT) type contract in South Africa. Extensive data on the pavement performance and traffic loading was collected as part of a detailed monitoring program since the opening of the road in 1997. This data was used to determine cost-effective and optimal maintenance actions in order to reduce life cycle costs. This case study illustrates how the measurement of pavement performance indicators and traffic were used to effectively design the maintenance actions required over the life of the pavement. This paper also includes a comparison of the actual pavement performance data collected for this 156.43 km long toll road with the performance as predicted by HDM-4 pavement deterioration models. An objective of this paper is to evaluate the appropriateness of the HDM-4 models for the specific climatic and traffic loading conditions that this specific pavement was subjected to. A significant feature of the comparative study is that the data used was collected on project level using short road segments and relatively short time intervals.