Requirements for road pavement performance were long centered unsafely but are currently being extended to such concerns as the environment, comfort, and costs. The following aspects must now be considered: (1) for safety: skid resistance, road-holding qualities, splash and spray reduction, and visibility of the road and road markings; (2) for economy: reduction of fuel consumption, tire and vehicle wear, and dynamic extra loads that may shorten the life of road (and engineering) structures; and (3) for user comfort and the environment of roadside residents: reduction of noise and vibrations inside and outside vehicles. Each feature of pavement performance is chieflyor partly determined by surface irregularities on different scales.Traditionally, three ranges of irregularities have been considered: microtexture, macrotexture, and roughness. Recent research into the relations between performance and pavement characteristics has revealed the part played by a hitherto unchecked range of irregularities: the so-called megatexture, with wavelengths between 50 and 500 mm, the adverse effects of which (noise, vibrations, and extra rolling resistance) used to be attributed to macrotexture. Megatexture is out of the measuring range of conventional test methods and devices but can now be checked with the new generation of contactless profilometers, such as laser profilometers. Thus it is possible, in principle, to optimise road pavement performance while meeting most of the requirements, even minor ones, by considering that some surface characteristics must be present (micro- and macrotexture) and that others are undesirable (megatexture and roughness). This paper appears in transportation research record no. 1215, Pavement management and rehabilita.ion
Abstract