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

The Task Force on Vehicles’ Sound (TF-VS) was established to review sound emissions regulations for M, N, and L category vehicles under UN Regulations 51, 9, 28, 41, 59, 63, 92, 117, and 138. The TF-VS will identify available studies, analyze data including Phase 3, review interactions between vehicle sound emissions and environmental noise, and propose improvements. THe group is chaired by France with OICA as Secretary and will focus initially on M and N vehicles.

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.

Introduces Real Driving Additional Sound Emission Provisions (RD-ASEP) for vehicles of categories M1 and N1 covering driving conditions outside of normal driving with higher accelerations and vehicle speeds up to 100 km/h

TFVS analyses of the feasibility of further limit value reductions and their effectiveness in real traffic conditions.