Present developments in the field of pavement-management systems are primarily concerned with seeking relations between users' costs and variable pavement parameters. In this respect, the description and assessment of pavement-surface characteristics with regard to vehicle-pavement interaction and its stochastic character are of extreme importance. Only such an approach makes it possible to obtain both justified criteria and sought limit values for the models describing their development during pavement performance under traffic loads and the effect of climatic factors.
The marked stochastic character is inherent not only in surface characteristics as such, but also in the response of the vehicle and measurement equipment during their travels along the pavement. Therefore, theoretical foundations are presented along with assessment methods, response-type measuring devices, and routine methods used in the measurements of surface characteristics of highway and airfield pavements based on the theory of random functions, which have been introduced in Czechoslovakia.
The ascertained relations of pavement-surface characteristics are expressed most frequently by means of power spectral densities. Numerous results of in-site measurements, particularly by the mass-scale data collection in the highway network, may be processed in such a way that simple analytical functions or numerical constants may be deduced. However, the solution is always based on random-process theory and respects the vehicle-pavement interaction.
This simplified approach also forms the basis of the classification of vehicle response by means of the variance of vertical acceleration and, in a derived manner, also the classification of pavement unevenness by means of a logically introduced unevenness index.
The selected probabilistic approach based on vehicle dynamics also causes certain difficulties and limitations, for example, in the identification of the pavement-surface megatexture band (wavelengths from 0.5 up to 100 m) or in the solution of the influence of the respective unevenness band on skid resistance, which concerns tire-pavement interaction.
In spite of these problems, the stochastic concept of the solution of the problems of pavement-surface characteristics can be considered an efficient instrument which can considerably accelerate the finding of the sought relations between the technical and economic parameters in the design of the structure and quantification of the couples in full management systems.