Proposal to address non-negligible differences in sound performance in cases where COP tests are carried out under conditions that differ from those used for the granting of the type approval. The proposal introduces conditions, procedures, and corrections to be applied to L_urban to account for the difference in test conditions.

Proposal by the Informal Working Group on Additional Sound Emission Provisions (ASEP) to introduce a transitional provision in line with the transitional provisions of Supplement 3. The new transitional provision should be added to the text of draft Supplement 5 to the 03 series of amendments to UN R51 which was adopted by the Working Party on Noise at its sixty-eighth session (GRB/2018/10).