Evaluation of Pavement Smoothness with a Digital Surface Model (DSM)

The evaluation of pavement smoothness and the calculation of smoothness index require the pavement profile. Among the techniques to obtain the profile, those with high profile accuracy are poor in efficiency; those with high profile efficiency is poor in accuracy. Furthermore, if the correct three-dimensional profile of the overall pavement can be obtained by photogrammetry, the smoothness can be assessed in a more comprehensive and efficient manner. This study reviewed smoothness measurement and digital surface models (DSM), and developed an intelligent road survey vehicle (IRSV). Firstly, a 100-m standard section was established by road and level. Then, the developed IRSV was driven to obtain images of the overall pavement within the three-lane width range including the left and right lanes of the vehicle's lane. After dense point-cloud matching of the images, a DSM was obtained. Three survey profiles of the standard section were extracted from the DSM, and ProVAL 3.60 was used to calculate the international roughness index (IRI) of these three survey profiles. Then, an institution accredited by Taiwan Accreditation Foundation used a walking profiler to obtain the profiles and IRIs for the three survey profiles for comparison purposes. The findings show that the ability of the IRSV to obtain the pavement profile is successfully verified.