12. The expert from the Russian Federation introduced ECE/TRANS/WP.29/GRB/2011/11, aimed at improving the test provisions for measuring the rolling resistance of tyres. The proposal received several comments (GRB-54-02, GRB-54-08 and GRB-54-10 amongst others). The Chair of GRB introduced GRB-54-12-Rev.1 proposing to amend ECE/TRANS/WP.29/GRB/2011/11. He clarified that the proposal did not affect the existing methods but result in a further option to the deceleration method. GRB adopted ECE/TRANS/WP.29/GRB/2011/11 as reproduced by Annex III to this report. However, some GRB experts suggested further technical assessment of the proposed alternative method to the next GRB sessions. The secretariat was requested to submit the proposal to WP.29 and AC.1, for consideration at their March 2012 sessions, as draft Supplement 1 to the 02 series of amendments to Regulation No. 117.

13. GRB noted also the work progress of the Working Party on Brakes and Running Gear (GRRF) on matters of common interest with GRB (ECE/TRANS/WP.29/GRRF/2011/12, ECE/TRANS/WP.29/GRRF/2011/29, ECE/TRANS/WP.29/GRRF/2011/30, GRRF-69-23, GRRF-71-29 and GRRF-71-31). Particularly, GRB endorsed ECE/TRANS/WP.29/GRRF/2011/30, inserting a new definition of C3 class tyres adopted by GRRF at its September session.