In the present work the major findings concerning the data analysisof a Long Term Pavement Performance study, focusing on the evaluationof the asphalt mix performance in relation to preventive pavementmaintenance, are presented and discussed. The performance studycomprised laboratory tests for both the original and the in-servicebituminous materials, as well as destructive and nondestructivetests on the in-service pavements. The stiffness of the existingasphalt concrete layers was estimated using laboratory mechanicaltests, traditional component analysis, as well as backanalysisbased on FWD tests. In addition, the fatigue strength of the existingasphalt mixes was estimated. After a longer time period the pavementremaining life predicted through the fatigue analysis was validatedby performing FWD tests on the non-maintained pavements, as wellas pavement condition distress assessments. The results of theanalysis showed that the interpretation of the asphalt mix performancebased on FWD tests can give useful information for possible rationalpavement preventive maintenance requirements. The laboratory estimatedasphalt mix properties are to some extent still necessary forsupporting the relevant engineering judgments for the interpretationof the FWD-based backanalysis.