A 3D calibration method was developed for a mobile laser scanning system developed in Finland. The measurement accuracy was validated using a robotic total station for reference measurements, with comparison of reference points with the triangulated surface measured by the laser scanning system. The calibration results are presented and analyzed. Propagation of random and systematic errors is analyzed mathematically. The adequacy of the accuracy is discussed while comparing the results to the tolerance requirements set by the owner, the Finnish Road Administration. The use of the laser scanning system in a design-buildmaintenance-operate project of a motor way in Finland is briefly illustrated.