Report of Pavement Surface Characteristics Mini-Rodeo (Mn/DOT Test Data and Data Comparison)

In June 2008, Rob Rasmussen and the Iowa State University / Transtec TPF 5-(124) team were in Minnesota to do some testing on cells in MnROAD. As Mn/DOT had only recently completed Spring On Board Sound Intensity (OBSI) and friction testing, the effort was considered as a Mini-Rodeo, few days removed. It facilitated comparison of our methods and results and particularly offered some degree of calibration. Transtec-Mn/DOT equipment variability did have a pronounced effect on the parallel tests. Mann Whitney Wilcoxon data comparison statistic performed at 95% confidence level corroborated the inference that the data set was similar and in consequence, each of the 2 sets of data will be accepted as representing the sections tested. Comparing spring / summer 2008 data to 2007 fall data, there is an increase in OBSI value. Further work will ascertain if this observation is a weather-related time-series issue or if the actual durability of sustained low Tire-Pavement-Interaction-Noise (TPIN) in the innovative grind needs to be examined. This sudden noise increase in cells 60 to 63 has been attributed to rocking panels and joint-slap.