In order to transfer from the conventional and empirical asphaltpavement design method used in Japan to a mechanistic design method,a test road was constructed on National Highway 36 in Hokkaido,in August 1990. The test road, called the Bibi New Test Road haseight different pavement structures. Since its construction, trafficmonitoring, and surface distress and deflection surveys have beenregularly conducted. Performance data have been obtained regardingsurface distress and deflection for up to 6.2 million of equivalent49kN wheel load. The performance curves in relation to the surfacedistress were approximated by the exponential function with correlationcoefficients of 0.98 and greater. The Structural Suitability Index(SSI), based on fatigue damage to the asphalt mixture, was proposedas an index of structural adequacy. The SSI performance curveswere approximated by the exponential function with correlationcoefficients of 0.93 and greater.