17. The expert from Norway reported on the outcome of the NordTyre projects conducted between 2011 and 2017 (GRB-68-09). According to him, for typical Nordic road surfaces, a good correlation between the actual noise levels and tyre noise labels had not been established. The expert from OICA was of the view that the tyre labelling systems would need to be improved and pointed out that both road surfaces and tyres equally contribute to the noise produced by the “tyre-surface” system by giving a 4 db(A) variation in the test results. The expert from ETRTO mentioned that the ISO 10844 standard on test tracks was under revision and that new test tracks would reduce by half the dispersion in the results.