Operational Considerations for Terrestrial Laser Scanner Use in Highway Construction Applications

Abstract

A 2010 survey of terrestrial laser scanner (TLS) usage among state highway agencies indicated that TLS is being increasingly used for highway construction applications among transportation agencies in the United States and Canada. To observe variations in TLS measurements for typical highway conditions, two roadway sites were studied; a 20-year-old asphalt surface and a new concrete surface. Repeated scans were conducted using a Leica ScanStation II to investigate the effects of pavement surface type and reflectance, point density, number and layout of targets, and survey method for establishing control points. Typical target arrangements were not found to greatly affect the resulting scan data for the equipment used in the study. It was observed in this case study that the collected TLS data demonstrated better relative elevation results based on the control and checkpoints established using total stations than on the control and checkpoints established using a real-time kinematic global positioning system. When using the Leica ScanStation II, reflectance of a sample of typical concrete pavement was not observed to vary greatly between 1-month-old and 1-year-old surfaces. Reflectance of asphalt pavement was observed to vary significantly between several examined surfaces ranging from new to 20 years old.