7. GRB resumed consideration on vehicle categories and their limit values on the basis of an existing database in China, Japan and EC. The expert from Japan introduced again GRB-56-05 and then GRB-57-22 explaining that according to the monitoring database in his country, the best fitting threshold for vehicle categories N2 and M3particularly should be 135 kW of power mass ratio (PMR). He continued that this value would encompass properly downsized vehicles that have a high impact on noise emissions from the vehicle fleets in Asian countries. He urged finding a compromise on vehicle categories and the adoption of a concrete proposal of the 03 series of amendments to the UN Regulation (i.e. ECE/TRANS/WP.29/GRB/2012/7). He stated that the introduction of additional sound emission provisions (ASEP) was much awaited in Japan. The expert from China gave two presentations (GRB-57-05 and GRB-57-06), to introduce possible compromise solutions (GRB-57-07) focusing on design characteristics as well as on PMR. The expert from OICA expressed appreciation for the efforts made by the expert from China to find convergence on the vehicle classification and introduced a possible compromise solution (GRB-57-19). The expert from Germany recalled that GRB started discussion with the agreement of developing a proposal for amendments focused on performance criteria rather than on design requirements. Moreover, he added that the allowance of 1 dBA for vehicles with direct injection diesel engines no longer justified. Finally, he recommended simplifying classes and subclasses, to avoid cumbersome vehicle classification thresholds that could hamper technical progress.

8. The EC expert informed GRB through a presentation (GRB-57-28) on the work progress of the European Union (EU) institutions on the EC proposal on vehicle noise. He showed that the European Parliament, at its plenary session, improved the EC proposal with the possibility of rounding the noise measurement values and using lower test acceleration (2 m/s2). He announced a further update for the September 2013 session of GRB and invited other Contracting Parties to provide information on the implementation of new noise limits at their national/regional level.

9. The expert from Switzerland introduced an analysis of the Swiss database based on vehicle noise tests (GRB-57-23) conducted in conformity to the 02 series of amendments to the UN Regulation and on limit values proposed by the experts from Germany, Japan and EC. GRB agreed to resume discussion on this subject at its September 2013 session and recommended experts to provide detailed comments.

10. GRB agreed to establish a group of interested experts on vehicle noise, led by the expert from EC, with the main goal of (i) finalizing a common proposal on vehicle classification (including subcategories) and (ii) update a proposal of 03 series of amendments to UN Regulation No. 51 aiming at maintaining consistency with the EU legislation proposal. The schedule of the first meeting of the group was agreed for 19 April 2013, tentatively in Brussels. Finally, GRB agreed to keep as reference in the agenda of the next session informal documents GRB-54-03, GRB-57-07, GRB-57-19 and GRB-57-23 and to resume discussion on the basis of the outcome of the meeting of the group of interested experts.