Measuring the International Roughness Index (IRI) is a significant research field in developing intelligent transportation infrastructure systems. This study employed a mobile laser scanning (MLS) technique to measure the IRI from the standard deviation of longitudinal roughness (σ). The MLS technology provides a rapid and affordable alternative that produces precise and dense point clouds along route corridors. The IRI is often used as an indicator to assess the state of a pavement surface. Since the middle of the 20th century, several sensing technologies have been devoted to improving performance, functionality, and sensitivity. Using MLS, the IRI data were obtained from routes in Kuwait's Khiran city. The longitudinal sectors of the sections were extracted from the 3D point clouds collected by the MLS technique with a length of 2100 m. The longitudinal section was divided into the centerline, outer edge, and inner edge. The IRI was calculated every 100 m along the three longitudinal sections, and it was found that it changed from 4.9 mm to 19.3 mm for the centerline, from 7.9 mm to 41.9 mm for the outer edge, and from 6.2 mm to 35.4 mm for the inner edge. From the results, the general condition of the road is poor to very poor. There is excellent compatibility between the visual inspection of the road and the results from MLS data.