The degradation of the acoustical properties of porous asphalt pavements is universally recognised. However the real evolution of these properties is difficult to evaluate as many factors can influence the measurement results making the analysis not so reliable. In this paper, attempts have been made in order to describe the degradation with traffic of both physical parameters and acoustical properties of porous asphalt pavements within a climatic region in the center of Italy. For this purpose two experimental pavement sections have been built in Tuscany and they have been monitored for three years in a joint research project. They are a single layer and a double layer porous asphalt pavements. The experimental measurements have been carried out every six months by performing tests both in situ and in the laboratory on pavement specimens. Analysis of the data has allowed degradation evaluation of both acoustical and physical parameters of the two pavement sections allowing interesting considerations to be made.