Roads are an important role in the transportation and the economy. Therefore, roads should be constructed under geometric standards to increase service life and maximize safety. However, landslides occurring around the road, especially in mountainous regions, may cause deformation on the road surface. Generally, landslide areas can be detected by measuring in more than one period. The proposed methodology investigates the landslide effect in a single period and consists of the following steps. First, a UAV collects data to generate a 3 D model. Then, an appropriate road project is designed according to the road geometric standards and 3 D model. Finally, landslides are successfully determined by comparing the appropriate road design and the current state of the road. It is found that there are road subsidence and rising areas up to 20 cm. As a result, it was determined the landslide had significant effects on the road surface with single-period UAV data.