The importance of tire/road noise as part of total vehicle noise has recently received growing attention. It has been recognized as a major component of passenger car noise, even at moderate speeds, and as a significant component of truck noise at high speeds. The continuing development of more silent vehicle power units will even more emphasize tire/road noise. During the last decade, in many countries, more deeply textured anti-skid road surfacings were implemented which appeared to be noisier and drew public awareness on what could be called "pave¬ment noise". As a matter of fact, the surface characteristics of roads are now known as the main factors influencing car tire/road noise. Then, in order to harmonize safety and environmental require¬ments and also to define a reference surface for measurement and regulation purposes, a better knowledge of the noise-relevant surface characteristics is required.