Strategic Planning for Optimization of Road-Building Materials in Overberg District Municipality in South Africa

Maintaining gravel roads to an acceptable level with increasing traffic volumes and social and environmental needs on the one hand and decreasing budgets and availability of suitable material on the other hand requires innovation and long-term strategic planning to keep agency and road user costs as low as possible. These conditions were identified in the Overberg District of Western Cape Province in South Africa, where a huge backlog for regravelling of roads has developed because of limited funding and difficulties in obtaining suitable materials. District municipalities act as agents to the provincial government and are therefore responsible for the maintenance of provincial roads within their regions. The average gravel thickness of the gravel wearing course on divisional and main roads in Western Cape Province has dropped from more than 80 mm to less than 40 mm in the past 10 years. Intense involvement in the Overberg District Municipality (DM) with gravel road maintenance, upgrading, performance monitoring, the finding of suitable road-building materials, and approval for mining has led to the realization that existing strategies for gravel road maintenance are inadequate to deliver acceptable service to the road user and to ensure that available material sources are optimally used. From an evaluation of needs and constraints within the DM, several factors have been identified as important contributors in the long-term planning of road maintenance and material utilization. This resulted in (a) a subdivision of the area as based on material availability, land use, topography, climate, and so forth; (b) identification of life-cycle maintenance strategy categories; (c) alternative approaches for material source selection and longer-term usage; and (d) the introduction of initiatives that help to reduce material demand. The approach followed to optimize both material sources and service delivery to the road user and preservation of the environment is discussed.