Terrain Model Resolution Effect on Sight Distance on Roads

Available sight distance is a key factor on road design. This research is focused on the effect of Digital Terrain Model (DTM) resolution on available sight distance. In addition, the effect of distance between calculation points along the vehicle path is also considered. The available sight distance is calculated using a Geographic Information System (GIS). Three high resolution DTMs, based on airborne LiDAR (Light Detection and Ranging), are used. Vehicle path is collected by a Global Navigation Satellite System (GNSS) mounted in a vehicle travelling along the road. Twelve combinations of DTM resolution and distance between calculation points along the vehicle path are studied. Results are statistically analysed and each case study is compared to a reference case which is considered close to reality. The analysis made shows that DTM resolution has a larger effect on the quality of the results than distance between calculation points. Practical issues are discussed