Evaluation of LIDAR-derived terrain data in highway planning and design

Surface terrain information is required to economically site new or relocate existing infrastructure facilities and make final design plans. Currently, ground surveying and photogrammetric mapping are the methods used by DOTS to acquire these data. Both methods are time and resource intensive since they require significant data collection and reduction to provide the level of detail necessary for facility location. The research presented here investigates a new method for collecting elevational data: LIDAR (Light Detection and Ranging). A pilot area previously mapped using photogrammetry by the Iowa Department of Transportation Office of Photogrammetry was selected, and surface grids of varying resolutions were developed from photogrammetric and LIDAR data. These were compared to determine the elevational accuracy of LIDAR. Additionally, the location processes of Iowa, Virginia and New Mexico are documented to determine how LIDAR data collection can be integrated into existing processes. The experiences of the Iowa DOT in the use of LIDAR are also presented