31. The secretary of the HDH group introduced GRPE-66-23 and GRPE-66-24, containing information on the HDH work progress. He summarized the thirteenth and fourteenth group meetings, underlining the decision to include a new annex in UN GTR No. 4, amending it. Having explained the status of validation test programmes, he required further input from Contracting Parties, by October 2013, on the assessment of chassis dynamometer and power-pack testing. He acknowledged that the Environmental Protection Agency of the USA requested to include powertrain testing and verification in the UN GTR and expressed the interest to take part in the second validation test programme. A drafting group for the UN GTR has been established, although the nomination of a technical secretary is still outstanding. A draft will be submitted to the next ordinary GRPE session, in January 2014, when a final report will also be submitted. The official submission of the text amending UN GTR No. 4 is expected for June 2014.