4. GRB resumed discussion on ECE/TRANS/WP.29/GRB/2014/4 by OICA proposing amendments to UN Regulation No. 28, in particular, a reduction in the prescribed sound level of the audible warning device from 93 to 87 dB(A). The expert from IMMA suggested further changes to this proposal (GRB-61-07). GRB adopted the proposal, as amended by Annex II to this report, and mandated the secretariat to submit it to WP.29 and the Administrative Committee of the 1958 Agreement (AC.1) for consideration and vote at their June 2015 sessions as draft Supplement 4 to the original series of amendments to Regulation No. 28. GRB noted that the adopted modification of the prescribed sound level makes this requirement less stringent and, thus, does not need a new series of amendments with transitional provisions.