45. As per paragraph 4, the experts from Austria and the Republic of Korea, on behalf of IWG, explained that validation of a reference of Human Body Models (HBM) was relevant for the evaluation of HIT (GRSP-73-03). She noted that validation consisted of simulations of HBM against a model representing a GVM frontend. She clarified that the procedure of validation of HBM was limited to pedestrian HIT. GRSP noted that two proposals of addendum to the Mutual Resolution No.1 (M.R.1) were submitted by the IWG to calculate HIT: (a) Addendum 5 on provisions for the DPPS GVM (ECE/TRANS/WP.29/GRSP/2023/7 as amended by GRSP-73-10-Rev.1); and (b) Addendum 6 on developing HBM qualification corridors (GRSP-73-11). GRSP noted that the development of the two Addenda needed further study and agreed to resume discussion at its December 2023 session.