ECE/TRANS/WP.29/GRSP/2019/26

(shown in Annex 5 of UN GTR No.7, Phase 1) is supplemented with an up-scaled Torso and Neck Link representing the CAESAR 2004 NL large male. The resulting calculations are presented as a table expressing the difference in back-of-head position (in direction X) between the mid-sized male (HRMD) and the large male (CEASAR NL 2004 male) at various torso angles and this is defined as Distance x. The test procedure for an effective head restraint height was reduced to merely goniometric measurements (excluding non-biofidelic interactions) and contained simply five steps (GTR7-08-03). 151. The point IP would be leading for the height measurement of the head restraint and also for checking a minimum height requirement for the front surface of the head restraint. This is recommended, since in Phase 1 some contracting parties expressed the wish to continue regulating a 100 mm minimum height requirement under their current regulation scheme.

(ii) Determination of Height requirement

152. The expert from the Netherlands proposed to measure the height by combining it with the backset to ensure the effectiveness of head restraints for tall occupants. At the second informal group meeting, the expert from the Netherlands pointed out that the backset was not considered under the methods of the current UN Regulation No. 17; Euro NCAP and IIWPG proposed a new evaluation method that combines the height and backset. In this evaluation method, measurements are only performed at the centre. Measurements according to this evaluation method would require the height to be raised by approximately 40 mm. Some methodological issues were pointed out, such as remaining uncertainties, reproducibility/repeatability, and hindrance to rear visibility. At the fourth informal group meeting, the expert from the Netherlands explained the status of their consideration of new head restraint height requirements. The head restraint height would be considered by measuring the backset based on the 95 percentile HRMD template proposed by the expert from the Netherlands. The evaluation of effectiveness had been reported in the accident analysis by EEVC (HR- 10-6). Japan pointed out that the evaluation method for active head restraints was necessary and that the timing of its delivery was important. The Chair noted that this topic could develop in parallel to the principal issue of developing a procedure for the BioRID dummy. He encouraged the expert from the Netherlands to define their proposal as soon as possible and asked that he considered the effect that the most recent changes to regulatory requirements had on taller occupants. He also welcomed the cooperation between the International Organization of Motor Vehicle Manufacturers (OICA) and the Netherlands to collect data on the head position according to the Realistic Anthropological Mathematical Systems for Interior Comfort Simulation by June 2011. 153. At the sixth informal meeting, a proposal on "a simple, pragmatic approach to effective height measurement" was submitted by a task force led by the expert from the Netherlands and including experts from OICA. It was decided that the task force would study the new method further and the result of the study would be reported in June 2011. 154. At the seventh informal meeting, the head restraint height task force reported its proposed new height measurement method and explained measurement of the backset and effective height of head restraints for 50th percentile and 95th percentile occupants and the problem of possible interference between Child Restraint Systems (CRS) and rear head restraint. A new method for measuring the head restraint width was also proposed. The task force reported that, to further improve the measurement method, it would continue to study different head restraint designs as well as issues related to UN Regulation No. 16 (safety-belts) concerning the interference problem with CRS. The SAE Human Accommodations and Design Devices Committee had some comments on the head restraint height measurement method, and the Chair noted that SAE would be welcome to contribute to the work. It was also agreed that the task force would make the data obtained from this work available to NHTSA. 155. At the eighth IWG meeting, the expert from the Netherlands presented the proposed effective height measurement method with a proposal of text of the regulation.