Porous friction courses (PFCs) are employed as surface layers primarily because of their functionality (i.e., their high permeability and noise absorption capability). In this study, the functionality of PFCs was evaluated through permeability and noise absorption tests in pavement structures of different thicknesses (i.e., 0.75, 1.5, and 2.5 in.), each at two air void contents (i.e., design and construction). Permeability was evaluated in the laboratory and the field with the Texas Department of Transportation (DOT) permeameter, the National Center of Asphalt Technology (NCAT) permeameter, and the Florida DOT falling head apparatus. Noise absorption was evaluated in the laboratory with the impedance tube. Results showed that, on average, the coefficient of permeability obtained with the Texas DOT permeameter was 67% higher than that obtained with the NCAT permeameter and 93% higher than that obtained with the Florida DOT falling head apparatus. In general, the coefficients of permeability increased with an increase in layer thickness. The noise absorption coefficient was not sensitive to thickness, but all values represented significant noise reduction. A permeability model on the basis of the KozenyCarman equation also was used to predict permeability values and relate them to the laboratory values obtained at different thicknesses. The equation accurately predicted the permeability coefficients of the thick PFC layers. The results suggested that minimum and maximum functionality requirements should be set to guarantee adequate performance.