20. The expert of OICA introduced draft amendments to the 02 series of amendments to UN Regulation No. 138 (GRBP-80-28), which took into account a new definition of “Exterior Sound Enhancement System” (ESES) proposed for UN Regulation No. 51 in ECE/TRANS/WP.29/GRBP/2024/22 submitted by OICA. According to OICA, UN Regulation No. 138 should remain a safety UN Regulation while the environmental concerns should be addressed by UN Regulation No. 51. GRBP noted that the two Regulations provide parallel specifications for an overlapping speed range (20 – 50 km/h).

21. Given the complexity of the problem and lack of time, GRBP was not in a position to take a decision on the proposals by the experts of EC and OICA. To make progress, the Chair suggested that the proposals be first considered within a new group of interest before GRBP would revert to them at the next session. GRBP agreed that discussions could first start in October 2024 in the framework of the new subgroup on UN Regulation No. 51 (see para. 14 above) with a later establishment of a separate subgroup on UN Regulation No. 138, if necessary.