Use of friction and texture in pavement performance modeling

The International Friction Index (IFI) is used for consideration of skid re sistance and macrotexture in a probabilistic pavement performance modeling framework. IFI provides a friction scale that can be used for comparisons a t international level and consists of skid resistance and macrotexture valu es, as macrotexture influences the variation of skid resistance by speed. T hreshold values are established to define high quality and low quality cond itions of skid resistance and macrotexture that are combined to assess the adequacy of pavement friction (IFI) for scheduling of maintenance activitie s. The methodology consists of three steps: (1) Use the local device-specif ic thresholds on friction and macrotexture to obtain rn threshold values; ( 2) determine a fixed IFI threshold value; and (3) obtain modified device-sp ecific threshold values based on the fixed IFI. Data for the present analys is have been collected on the Hungarian asphalt-concrete motorway system be tween 1994 and 1997. The condition states based on the modified device-spec ific threshold values are used to establish a Markov chain model that is in good correlation with the actual performance data.