South Africa’s provincial and municipal road authorities are responsible for the maintenance of an extensive low-volume gravel road network. Given the significant deterioration in the quality of this network, it is questionable whether authorities can and should accommodate the relative maintenance intensity of gravel roads within the resource constraints they face. The high incidence of gravel roads was largely driven by decentralized provision and relatively cheap construction costs compared to sealed alternatives, but consideration should extend to the resources that are required for the routine maintenance and periodic re-gravelling necessary to uphold their design life. Planning generally was not extended over the life-cycle of low-volume roads, so shocks have been encountered with respect to haulage distances for gravel, erosion of longitudinal road gradients, climate change, and increases in traffic volumes. We therefore estimate and stress test the whole-life economic asset cost of a gravel road under South African conditions, and compare these results against a variety of sealed alternatives to determine the points at which gravel is no longer the most cost-effective surface option for low-volume roads. Each alternative surface includes a specification, schedule of inputs, and standard maintenance programme. The stress tests focus on variations in input prices, the potential labour intensity of road works, the cost of labour, road user costs, and the sensitivity of maintenance schedules and costs to environmental factors.
Don Ross and Matthew Townshend
General, Finances & Economics, Governance