Qualitative assessment of Traffic Speed Deflectometer data collection practice

Traffic Speed Deflectometers (TSDs) are being used more frequently for pavement evaluation at traffic speeds. Although it has been established that TSDs can assess pavement conditions at the network and project level, the quality of the obtained data needs to be further evaluated and factors affecting the magnitude and trends of the pavement responses should be more deeply investigated. In this study, TSD field experiments were conducted on several diverse instrumented pavement sections under different operational conditions. The effects of parameters such as data collection interval, vehicle operational speed, pavement section structural strength, and deflection velocity magnitude were investigated. Although the vehicle speed did not significantly affect the magnitude of the deflection slopes, it impacted the variability of the measured raw data. Pavement stiffness also directly impacted the quality of the data. Stiffer pavements, including pavements with either thick asphalt layers, stabilised base layers, or rigid pavements, responded to the moving load with lower deflection velocities and higher variabilities. Averaging the obtained data over longer intervals can reduce the variability of the deflection parameters. © 2024 Informa UK Limited, trading as Taylor & Francis Group.