111. The representative of the United Kingdom, on behalf of the Chair of the IWG on UN GTR No. 7 Phase 2, gave an oral report on the work progress. He informed AC.3 that, as a result of its activities, the group had agreed on: (i) an effective head restraint height measurement procedure and (ii) an appropriate dynamic test, including the test procedure and the associated corridors for the Biofidelic Rear Impact Dummy (BioRID II). However, he added that the development of injury criteria for the use of the BioRID II was at a critical point, because medical research in the United States was still progressing but not as rapidly as was expected. As the deadline of the IWG is December 2013, he sought AC.3 guidance on whether the upcoming proposal of UN GTR could be delayed by more than one year to encompass as a whole the two above-mentioned issues or to proceed in two steps: adopt (i) the measurement of height of head restraint and then (ii) the dynamic test procedure with the dummy and the associated injury criteria. AC.3 preferred to proceed in a one-step approach, to consider a complete proposal, including a draft Addendum to M.R.1 and agreed to extend the mandate of the IWG until the end of 2015.