156. The expert from the United States of America, in his capacity of Chair of IWG on Quiet Road Transport Vehicle Global Technical Regulation (QRTV GTR), recalled his statement at the previous session of AC.3 about the publication, in November 2016, of the US National Rule on Minimum Sound Requirements for Hybrid and Electric Vehicles. He also recalled that the World Forum had agreed to extend the mandate of IWG on QRTV GTR until December 2018. He reported on the national procedures for the entry into force of the National Rule and pointed out that its effective date of implementation would be 21 March 2017, with the phasing-in period of 2019-2020 (www.regulations.gov/docket?D=NHTSA-2016-0125). He further indicated that IWG QRTV GTR would shortly resume its work by undertaking a detailed analysis of differences between UN Regulation No.138 on QRTV and the US National Rule, with the aim to prepare compromise wording for the gtr.