A correlation between laser-based device and close range photogrammetry technique for road pavement macrotexture estimation

Both public and private roads Agencies face the problem of having to guarantee high levels of service and safety on their managed roads, having limited economic resources available. In this context, the necessity to accelerate and improve the monitoring techniques for road pavement quality, promotes the research towards the development of easily accessible and reliable tools. For this purpose, the present work shows the preliminary results obtained from the application of photogrammetric techniques to the evaluation of the macrotexture of road pavements. In fact, it is widely recognized that macrotexture is a fundamental indicator for indirectly defining the grip level of a road pavement, especially in the wet conditions. In order to investigate the correlation between laser scanning and photogrammetric technique, in terms of Mean Profile Depth (MPD), three different road pavements have been selected and two test points for each of them, have been studied. The three-dimensional models of the six test points have been developed for both laser scanner and photogrammetry acquisition methods and six hundred profiles have been ana lyzed. Preliminary results have shown an acceptable correlation (R2 = 0.956 and Pearson = 0.98) between MPD values obtained from both three-dimensional reconstructions, con firming the potential of the photogrammetry also for the road pavement surface acquisition and macrotexture characterization.