Representativity of ISO test track surface based on controlled pass-by measurements

Within the Polish-Norwegian research project ELANORE, a limited Round Robin Test has been performed on four ISO tracks in Northern Europe. The basic objective of the project is to improve the EU directive on labelling of tyres for noise and rolling resistance. This directive is based on the measurement procedures proscribed in the UNECE Reg.117. Measurements on 3 ISO tracks were performed in 2021 and presented at InterNoise 2022. This paper adds results from tests conducted on a fourth ISO track as well as on trafficked roads with different conventional pavements: 2 in Norway (MA11 and SMA16) and 3 in Poland (SMA8, SMA11 and EACC). On all ISO test tracks and road test sites the same car, test tyres and test equipment as well as the same personnel were used to minimize the measurement uncertainties. Measurements were done using the controlled pass-by (CPB) method for vehicle test speeds between 40 and 90 km/h, with 2 test conditions: according to Reg.117 and with so-called "light test conditions". The main conclusion is that the noise ranking of the tyres on both, the ISO tracks and conventional pavements do not correspond to the ranking based on the label values given by tyre manufacturers.