Development of safety related investigatory level guidelines : a worked xxample of methodology.

This report provides a worked example for developing skid resistance investigatory level guidelines. The worked example is sourced from Main Roads Western Australia (MRWA) and relates to texture measurement as a surrogate for skid resistance. A limited number of roads were randomly selected from the MRWA network survey database and used for the development of the guidelines. Correlations between crash rate and texture depth at different site categories and different surface conditions (wet or dry) were examined and analysed. With generally satisfactory correlations between the two key parameters displayed, an example of MRWA texture depth investigatory level guidelines was devised. The report provided a worked example to describe the steps taken in working through the method. (Author/publisher)