Volume 3, Issue 9 (October 2006)
Realistic Approach for Enhancing Reliability of Pavement Surface Friction Testing
This paper presents the state-of-the-practice by the Indiana Department of Transportation (INDOT) in enhancing the reliability of pavement friction testing with the ASTM Standard E 274-97  locked wheel tester. In order to detect the potential changes in system performance, INDOT conducts weekly and monthly system verification on a special friction test track. A multiparameter method has been used in assessing the performance of the locked wheel tester. This method cross examines the sample mean, the standard deviation, and the coefficient of variations of the friction measurements saved in a dynamic friction database that is upgraded after each verification testing. It was found that the system performance of the locked wheel tester varies with the type of test tire and pavement surface characteristics. The smooth tire produces greater friction variations than the ribbed tire. As pavement surface becomes rougher, friction variations decrease. A realistic approach has been established for verifying system performance.