Representativity of longitudinal road profiles

The longitudinal profile of a road pavement represents by definition a simplification of the ride plane surface characteristics along a vertical section, which is not necessarily repeated identically in different parallel transverse paths. The execution of evenness tests on single alignments thus does not always prove to be suitable for representing the effective functional characteristics of road surfaces, especially in urban areas where the presence of localized irregularities becomes a primary factor in road pavement evaluation. The research described in this paper is an extension of a previous study investigating the effects of randomness or stability of the profilometric surveys of road surfaces along parallel longitudinal alignments, referred to five different urban contexts. Alignments were located with a transverse step of 0.50 m to guarantee 10 surveys for each surface. The acquisition and successive numerical processing of the profilometric data also allowed the stability to be verified of the evenness indexes currently used in a transverse direction (IRI, RN, RMS), contributing towards emphasizing how much the choice of alignments can sometimes be highly determining on the final result of pavement evaluations.