Tire-pavement friction and pavement surface texture are very important safety characteristics that need to be considered in pavement surface design and monitored throughout the life of the pavement. This paper compares friction measurements obtained with different equipment (three locked-wheel trailers with smooth and ribbed tires and one Dynamic Friction Tester) and at different speeds. Five tests in each lane at each speed were conducted on each of eight pavement sections with a wide range of surface textures. The paper also compared the relationship between friction and speed for the different pavement sections and devices and the International Friction Index values obtained using the different equipment and tires. The investigation showed that the repeatability of the various locked-wheel trailers evaluated was considered acceptable and that the reproducibility obtained with the same type of tire was also good at the various speeds considered. The correlation between the measurements using the locked wheel trailers with the smooth and ribbed tires did not correlate that well to each other, when all of the evaluated pavement surfaces were included in the analysis. In all cases the measurements obtained with the ribbed tire were higher than with the smooth tire. Finally, discrepancies in the IFI F60 values calculated for the different devices suggest that the original coefficients determined during the PIARC experiment may need to be adjusted for the device evaluated before the IFI can be implemented in the participating agencies.
Samenvatting