Experimental Evaluation of a Pavement Imaging System

Abstract

The Florida Department of Transportation (FDOT) has acquired and validated a multifunctional survey vehicle for the collection of highway pavement–related data at normal operating speeds. With its ability to collect pavement, right-of-way, and side-view images together with position location, cross-slope, grade, curvature, rutting, and roughness data, this state-of-the-art vehicle enables the rapid and automated evaluation of roadway performance and identification of hazardous conditions. Manual surveys that involve a high degree of subjectivity, a low production rate, and exposure to hazardous conditions are still the most widely used means for evaluating pavement distress. The pavement evaluation subsystem of the FDOT survey vehicle represents an efficient, cost-effective, and safe alternative for the collection and evaluation of pavement distress data. In the research reported in this paper, the precision and accuracy of the pavement imaging subsystem was tested under different lighting conditions, speeds, pavement types, and with or without the special pavement lighting system. The evaluation of pavement image quality has been achieved with the signal-to-noise ratio. Moreover, the effect of the vehicle's speed and the geometrical distortion in the image caused by optical distortion and distance measurement sensor error were also investigated. The conclusions and the recommendations drawn from this study can be used to identify the limitations of automated surveys and to determine the optimum conditions for the most accurate distress evaluation.