The provisions of UN Regulation No. 16 (paragraph 6.4.1.4.1.) only allow contact of the chest of the dummy driver with the steering assembly, provided that this contact fulfils certain energy-dissipation test requirements and that contact does not occur at a speed higher than 24 km/h. In response to the updated provisions of UN Regulation No. 16 which allow greater forward displacement of occupants, UN Regulation No. 17 will be updated to provide requirements on improved energy-dissipation criteria for those areas of the rear of seats and head restraints where impact of the head of the rear occupant may occur. Given the update to UN R17, this proposal would amend the scope of UN R25 (which has not been updated with regard to energy dissipation) to cover only vehicle categories M2 < 3.5 tons and N1 and mention explicitly that application to N2 and N3 vehicle categories is optional.
32. The expert from the Netherlands introduced ECE/TRANS/WP.29/GRSP/2015/22 on changing the scope of the UN Regulation and removing alternative routing for approval of seat backs which are fitted with head restraints (see also agenda items 11 and 12). GRSP, agreed to refer the proposal to the group of interested experts on new restraint system technology (see paras. 27 and 30 above) and resume discussion at its May 2016 session.