Proposal from the Noise Measurement Uncertainties informal group to to reduce variability of measurements.

Text pursuant to 21 September drafting group session.

Text pursuant to the 21 September drafting group session.

Draft text integrating input from the Sound Measurement Uncertainties informal group pursuant to the 21 September drafting group session.

Draft text integrating input from the Sound Measurement Uncertainties informal group pursuant to the 21 September drafting group session.

Based on GRBP-74-22 plus measurement uncertainties provisions.

IWG on Measurement Uncertainties identified the temperature behaviour of tyre rolling sound component as a contributor to the measurement uncertainty of pass-by noise tests. Since in UN Reg. No.117 a temperature correction of tyre rolling sound is already established the group investigated an adoption of the existing calculation procedure. Due to the different testing conditions in UN Reg. No.117, new scientific investigations and industry data in pass-by testing the group worked out a temperature correction, which is adopted to the requirements of UN Reg. No.51.