Survey of state practices to control skid resistance on hot-mix asphalt concrete pavements

A nationwide survey on design methods for achieving adequate skid resistance on hot-mix asphalt concrete pavements was conducted. Information was collected on the design practices used by 48 state departments of transportation (DOTs) in the contiguous United States. Survey findings show that the emphasis placed on the skid resistance aspects in various state DOT design procedures vary considerably. Based on the data collected, 21 out of 48 state highway agencies either do not have any design guidelines specifically addressing pavement skid behavior or assume that adequate skid resistance may be ensured through proper mix design. The general approach used by these agencies involves frequent monitoring of pavements to identify pavements with skid-related problems so that appropriate action may be taken. Survey findings indicated that state DOTs that consider skid resistance in their design procedures emphasize controlling the quality of coarse aggregates used in pavement surface course construction. The procedures used for aggregate qualification, however, vary significantly from one state agency to another. Some state DOTs rely on simple aggregate classification methods based on aggregate type, whereas others perform detailed laboratory evaluation. The laboratory test procedures that are most commonly used in evaluating aggregate frictional properties are the polish value test, acid insoluble residue test, and petrographic analysis. In addition to laboratory testing, Florida, Kentucky, Pennsylvania, and Texas use alternative procedures to qualify aggregates based on their field skid performance.