12. The expert from the Netherlands presented a study (GRB-62-09 and Add.1) on noise emission from the Original Equipment Manufacturer (OEM) tyres of a specific size which were found to be around 1 dB(A) lower than the one from replacement tyres of the same size. The expert, thus, proposed to further reduce the limit values for OEM tyres in the 02 series of amendments to Regulation No. 117 (GRB-62-11 and Add.1).

13. The expert from Switzerland expressed his support for the general direction of the Dutch proposal. The experts from Germany and EC were of the view that, at this stage, it would be premature to tighten the tyre noise limits of Regulation No. 117. The expert from France called for a holistic approach to this issue. The experts from ETRTO and OICA expressed doubts about the representativeness of the tyre sample used in the Dutch study. The expert from ETRTO also delivered comments on the proposal for amendments to Regulation No. 117 (GRB-62-17). Finally, GRB invited all experts to further study the Dutch proposal and decided to revert to this issue at the next session.

18. The expert from the Netherlands recalled the two studies presented at the previous session of GRB and introduced further arguments for tightening tyre noise limits in Regulation No. 117, together with the text of draft amendments (GRB-61-03 and Add.1). The expert from ETRTO questioned if the pool of tyres selected for the Dutch studies had indeed been a representative sample (GRB-61-18). He further pointed out that, for the time being, the tyre industry was busy meeting the requirements of 02 series of amendments to Regulation No. 117 which had recently come into force, in November 2012. According to him, until the completion of this process by 2018-2020, it would be premature to consider further reducing of tyre noise limits. The experts from China, Norway and Switzerland agreed that the proposal by the Netherlands needed further study. The experts from France and Germany pointed out various problems with labelling of tyres. GRB invited experts to provide their comments on the Dutch proposal and decided to revert to this issue at the next session on the basis of a new informal document containing the draft amendment proposals tabled by the expert from the Netherlands in GRB-61-03.

14. The expert from the Netherlands presented the outcome of a study (GRB-60-08 and Add.1) of the shifts in tyre sound emission levels in his country between 2007 and 2013, i.e. before and after the revision of tyre noise limits in 2009 (EC/661/2009 and UN Regulation No. 117). The study addressed the most common C1, C2 and C3 tyres in terms of size and manufacturer. The reductions in tyre sound levels between 2007 and 2013 were found to be respectively 1.5, 1.4 and 1.1 dB(A) for C1, C2 and C3 tyres.