The Danish Road Directorate and Greenwood Engineering have developed laser-based High Speed Deflectometer to measure the bearing capacity of roads at normal traffic speed. Previously Denmark used the falling weight deflectometer (FWD) to determine the bearing capacity of roads, but the system only collected information at individual points while the FWD is stationary. This made testing on motorways expensive and difficult. The new system enables measurements to be taken at a driving speed of 70 km/hour. The system could test all lane-km in the Danish country road network in 12 weeks. The High Speed Deflectometer is based on laser technology patented by Greenwood Engineering. The testing equipment is mounted on a long trailer towed by a standard truck. Test results obtained with a prototype on a section of motorway M30 are reported.
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