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.
6. The expert from IWG MU briefly introduced a second package of draft amendments to UN Regulation No. 51 (GRBP-74-13). GRBP also noted an updated reference document with a general approach to estimate measurement uncertainties (GRBP-74-11) and was of the view that this document could be applicable to UN Regulations beyond the scope of GRBP.