This project studies the ways in which tire noise changes as the pavement on which they run ages and wears. Initial measurements of the levels and spectral distribution of noise generated at the tire-road surface interface have been made on a number of road surfaces of a variety of asphaltic and concrete compositions. In all, noise characteristics from thirty-one roadway sections are under biannual study. All of these sections were freshly completed within six months of the initiation of the study. Data from the first four biannual sessions are presented in graphical form.