In the present work the major findings concerning the data analysis of a Long Term Pavement Performance study, focusing on the evaluation of the asphalt mix performance in relation to preventive pavement maintenance, are presented and discussed. The performance study comprised laboratory tests for both the original and the in-service bituminous materials, as well as destructive and nondestructive tests on the in-service pavements. The stiffness of the existing asphalt concrete layers was estimated using laboratory mechanical tests, traditional component analysis, as well as backanalysis based on FWD tests. In addition, the fatigue strength of the existing asphalt mixes was estimated. After a longer time period the pavement remaining life predicted through the fatigue analysis was validated by performing FWD tests on the non-maintained pavements, as well as pavement condition distress assessments. The results of the analysis showed that the interpretation of the asphalt mix performance based on FWD tests can give useful information for possible rational pavement preventive maintenance requirements. The laboratory estimated asphalt mix properties are to some extent still necessary for supporting the relevant engineering judgments for the interpretation of the FWD-based backanalysis.