5. The expert from the Informal Working Group on Measurement Uncertainties (IWG MU) presented their final report (GRBP-79-02) and a draft document for reference (ECE/TRANS/WP.29/GRBP/2024/8 and GRBP-79-48-Rev.1). During an in-depth discussion, several experts from contracting parties expressed concerns about the formal adoption of the document for reference and its legal status. They pointed out that the document could be misinterpreted as being legally binding and modifying the established sound limits in UN Regulation No. 51. In the absence of consensus, GRBP postponed the discussion to the next session.