In order to transfer from the conventional and empirical asphalt pavement 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 has eight different pavement structures. Since its construction, traffic monitoring, and surface distress and deflection surveys have been regularly conducted. Performance data have been obtained regarding surface distress and deflection for up to 6.2 million of equivalent 49kN wheel load. The performance curves in relation to the surface distress were approximated by the exponential function with correlation coefficients of 0.98 and greater. The Structural Suitability Index (SSI), based on fatigue damage to the asphalt mixture, was proposed as an index of structural adequacy. The SSI performance curves were approximated by the exponential function with correlation coefficients of 0.93 and greater.