Current skid resistance monitoring programs and investigatory levels (ILs) used in Australia are derived mainly from systems developed in the UK, and these may not be applicable to Australian conditions. An approach is proposed which replaces skid resistance ILs with macrotexture ILs for high speed roads. UK and Australian studies showed a strong correlation between accident rate and macrotexture for high speed roads. Evaluation of the new approach on a pilot network in Western Australia showed that 85 per cent of the length would be subject to macrotexture IL which can be measured more cost effectively and reliably than skid resistance. A computer program was developed to assign site categories to road sections in the pilot network using information from the Main Roads Western Australia (Main Roads) database. Database information was also used to estimate the skid resistance of road sections, and to thus identify those at risk of not meeting skid resistance ILs. Analysis of results for the pilot network indicated that only category 1 sites (traffic light controlled intersections, pedestrian/school crossings, railway level crossings, etc.) were at risk of not meeting ILs, and these represented 0.3 per cent of the network length. Of the sites assigned a macrotexture IL, 18 per cent were below the proposed lL of 1.0 mm sand patch, and these represented 15.6 per cent of the network length. (a) For the covering entry of this conference, please see ITRD abstract no. 0612AR242E.
Abstract