Development of the UK highways agency traffic speed deflectometer

One of the headline objectives of the UK Highways Agency (HA) is to reduce congestion and improve road safety whilst undertaking highway maintenance. To this end the HA has invested significant resources in appropriate technology to collect road condition and structural data at traffic speed. Surface condition surveys of the English strategic road network are already carried out using survey vehicles operating up to 100 km/h, however currently there is no traffic speed facility for measuring the structural condition of the road network. Deflection measurements remain the most reliable non-destructive method for determining the structural condition of flexible pavements and therefore in 2005 the HA instructed TRL to procure a prototype Danish Traffic Speed Deflectometer (TSD), on their behalf, and tasked them with developing it into a survey tool capable of providing an estimate of structural condition. This paper presents the results of the TRL project to date and concludes that, with further development, the HA TSD will be capable of measuring structural condition at traffic speed.