23. GRSP resumed discussion of ECE/TRANS/WP.29/GRSP/2019/19 on limit values on the chest vertical acceleration of Q-dummies during the dynamic testing of ECRS, as agreed at its December 2019 session (see ECE/TRANS/WP.29/GRSP/67, paragraph 41). The expert from CLEPA recalled to GRSP that this decision aimed to allow the collection and analysis of data monitoring. The expert from CLEPA clarified (see GRSP-67-23) that data were subsequently provided by the Type-Approval Authority and the Vehicle Certification Agency (VCA) of the United Kingdom. He added that these were supplemented with a sample from CLEPA, in order to derive the proposed limits for tension force, Fz and flexion moment. He then introduced a proposal (see GRSP-67-24) of amendments to the injury assessment criteria for frontal and rear impact to specify limit values for tension force and flexion moment measured in the upper neck of the Q0, Q1 and Q1.5 dummies. However, he recommended that other contracting parties also provide monitoring data to support this analysis and confirm the proposed limits. GRSP endorsed the request of the expert from CLEPA and agreed to resume discussion at its December 2020 session based on a revised official proposal. Moreover, the experts from the Global NCAP and ANEC on behalf of CI withdrew ECE/TRANS/WP.29/GRSP/2019/19. GRSP agreed to defer consideration of GRSP-66-28 to the December 2020 session, due to the lack of time.