ABSTRACT
This paper presents some of the results of the field evaluation of the Traffic Speed Deflectometer (TSD). The evaluation was performed with the participation of nine state highway agencies that are members of a national pooled fund project. The paper presents various methods used to analyze the pavement structural conditions obtained from the TSD, which include (1) measurements of deflection slope directly obtained from the TSD, (2) pavement deflections calculated from the measured deflection slopes, and (3) structural indices such as the Structural Curvature Index (SCI) and the effective structural number (SNeff). The results show consistent error standard deviation of TSD measurements. The TSD was able to identify pavement sections that varied in structural condition. Comparison of the calculated effective structural number with TSD measurements, using an empirically developed equation by Rohde, with the SNeff calculated by the Pennsylvania Department of Transportation (PennDOT) Pavement Management System based on construction history, showed similar trends, although the TSD calculated SNeff was higher.
