Development Of A Direct Type Road Roughness Evaluation System

Roughness is an important indicator of pavement riding comfort and safety. It is a condition indicator that should be carefully considered when evaluating primary pavements. At the same time, the use of roughness measurements plays a critical role in the pavement management system. There are many devices used for roughness evaluation. The major tools used for road roughness quantify are the road profilers. In the thesis research, in order to obtain useful pavement surface condition data for pavement evaluation, two direct type road roughness evaluation systems were developed with the combination of modern sensor technology and computer technology. The thesis will focus on the development of the direct type profiler systems, including the improvement of the hardware design, the new direct type road roughness-measuring system using different method, the software development, which makes it more functional. In order to evaluate the accuracy and correction of the direct type profiler system, different roughness devices (including FDOT High-Speed laser profiler, FACE Dipstick and direct type I profiler) were operated in 4 calibration sites. The research focused on several performance measures, such as correlativity, repeatability. IRI and RN results from these devices were analyzed to evaluate the correlativity between these devices. After verified that direct type I profiler has good repeatability and correlation with FDOT High-Speed laser profiler, FACE Dipstick, 10 calibration sites data in Tampa were collected using direct type I profiler and direct type II profiler. The repeatability and correlation analysis between the two profilers were performed. From field experiments and data analysis, it shows: 1.Direct type I profiler showed satisfactory repeatability performances; 2.Direct type I profiler has good RN correlations High-Speed laser profiler; 3.Direct type I profiler has good correlations with Dipstick, High-Speed laser profiler in terms of IRI 4.Direct type II profiler does not has good correlation with direct type I profiler; the performance needs to be improved. Except for these conclusions, it is also found that the High-Speed profiler can be operated at different speeds with little differences in RN values, the sampling rate did show impact on RN value