IMPROVING THE SKID RESISTANCE AND COST EFFECTIVENESS OF ROAD MARKING MATERIALS IN SOUTH AFRICA

Most of the road markings in the Republic of South Africa have been laid with ordinary road paint. Measurements using the British portable pendulum tester show that the skid resistance of ordinary road paint is very low and presents a real danger especially to motorcyclists. The effects of repainting, wear, the addition of retroreflective glass beads and the addition of aggregates to form "non-skid" paints are discussed. Various alternative materials are considered. Skid resistance measurements showed that thermoplastic should improve safety because its skid resistance is at least equal to that of the road surface. Its major disadvantage is its higher initial cost, but measurements of the durability and effectiveness of the various road marking materials show that thermoplastic is the most cost-effective. "Non-skid" paints are nowhere near as effective but are nevertheless a considerable improvement upon ordinary road paint. It is therefore recommended that "non-skid" paints be substituted for the existing ordinary road paints in the interim and that experience should be gained in the use of thermoplastic in order to develop the confidence necessary to make a changeover to thermoplastic. Use of thermoplastic materials would give greatly superior road markings at no extra annual cost. For the covering abstract of the conference see IRRD 288720. (Author/TRRL)