Being able to collect existing site conditions quickly and accurately represented in three dimensions can be achieved with remote sensing technology, such as with the use of terrestrial or airborne equipment, including UASs.
LiDAR is a geospatial technology that allows the rapid and geospatially accurate acquisition of roadway asset data by using a sensor to scan the project area, resulting in what is known as a point cloud. This cloud is composed of billions of points that depict the existing conditions almost as clear as a photograph. UAS, which is a geospatial data delivery platform, uses low-altitude aerial photography or LiDAR to create similar point clouds.
Both technologies rely on global navigational satellite systems (GNSS) to pinpoint a location in the world. The main benefit of these two technologies is that, when captured to the necessary degree of resolution, data can be collected once, but used many times for different purposes because the accuracy and integration of the information is such that when planned properly, it can meet survey design accuracies as well as general positioning.
According to a 2017 Oregon State University Study, the investment of a mobile LiDAR mapping system is recovered within one year of collecting information for multiple applications. For example, the Oregon Department of Transportation invested over $1 million to deploy one mobile mapping system, resulting in a savings of almost $5 million over a five-year period.
While a nearly 250 percent return-on-investment is impressive, having the 3D survey information readily available to support 3D design projects, asset management inventory, bridge vertical clearances, and maintenance preventive work is the real value of this mature technology.