APPLICATION OF LIGHT DETECTION AND RANGING (LIDAR) TECHNOLOGY TO OREGON HIGHWAYS

Light Detection and Ranging (LiDAR) coverage is expanding rapidly in Oregon. LiDAR acquisition is managed by the Oregon Department of Geology and Mineral Industries (DOGAMI) and funded through the Oregon LiDAR Consortium (OLC). The OLC consists of numerous federal, state, and local agencies as well as Tribal governments and other nongovernmental organizations. The Oregon Department of Transportation is a significant contributor to the OLC, and a beneficiary of the combined effort by applying the data to the state’s highways in numerous ways. Applications include terrain analysis to identify drainage patterns, culvert locations, wall dimensions, embankment and cut limits, unstable slopes, and wetlands.

LiDAR datasets are typically analyzed for geologic/geomorphic analysis using ArcGIS where hillshade images and topographic contour maps created from the bare-earth data. LIDAR data can also be imported directly into common engineering software. Preliminary engineering efforts to assess the viability of projects such as realignment and widening alternatives can be completed in a timely fashion as preliminary-phase survey information is readily available. Significant savings can be realized by focusing final design ground surveys to the selected alternative.

LIDAR is currently being extensively utilized as part of ODOT’s Unstable Slopes program. This asset management program is identifying all known landslide and rockfall areas impacting the state highway system. Tremendous time savings are now being realized because field-generated sections can now be generated in GIS using the LIDAR data. Conservative estimates indicate the initial data collection can be accelerated by up to 3-5 years.

As part of the Unstable Slopes program, ODOT is also mapping landslides currently crossed by state highways but not necessarily impacting the roadway. The advent of LiIDAR makes the identification of landslides previously masked by Oregon’s heavy vegetation coverage much easier. This information will assist ODOT planners and designers with early notification of potential landslide hazards. This is critical to minimizing the impact of unstable slopes on a project and providing the time necessary to appropriately address the hazard.