EVALUATION OF ROUGHNESS SYSTEM OF AUTOMATIC ROAD ANALYZER

The automatic road analyzer (ARAN) is a multifunction road-quality surveying instrument. The roughness measuring system is one of the subsystems of the ARAN unit. To enhance the understanding of the response of this instrument (so as to apply it more efficiently to pavement management), a research study was conducted by the Center for Transportation Research, University of Texas at Austin, to comprehensively evaluate this instrument. The results of evaluating the roughness subsystem of the ARAN unit, including roughness correlation analysis and development of a new present serviceability index (PSI) model, are presented. In the correlation analysis, roughness data were collected in Texas by the ARAN unit and the Texas Department of Transportation modified K.J. Law profilometer that was used as a standard reference. The evaluated roughness statistics of the ARAN unit were root mean square vertical acceleration (RMSVA), mean absolute slopes (MAS), and TEXTURE. These roughness statistics were correlated with the roughness statistics of the profilometer Maysmeter output, serviceability index (SI), and international roughness index. The PSI model developed in this study is based on the roughness statistic SI of the modified K.J. Law profilometer. This PSI model, including RMSVA and MAS that are independent variables, shows good correlation with SI of the profilometer.