This revised document intended to present to amend 117 the timetable for the work related to Regulation No. 117 has been shifted with approximately 12 months for this part.
The aim of the IWG is to propose harmonized measures for evaluating systematic errors and random errors to improve the test procedures to reduce measurement uncertainties

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.

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