Mr. Zander presented an overview on document GTR9-6-08. He pointed out that it is not the intention of BASt to change the injury criteria. Mr. Zander explained the process used at BASt to derive the threshold values and noted that his approach was slightly different than the approach of JAMA/JARI. He also highlighted the agreements made during the work of the former FlexPLI Technical Evaluation Group (TEG) on the FlexPLI thresholds. He concluded that, however, as both approaches were combined the impactor threshold values also depend on the actual performance of the latest impactor version and therefore should be adapted accordingly, if necessary.

Dr. Konosu presented document GTR9-6-12 that explains how the FlexPLI model was validated at JAMA/JARI. Dr. Konosu showed that in the process used in Japan the performance of the impactor does not influence the impactor thresholds.

On behalf of OICA members Mr. Kinsky presented the findings of industry (document GTR9-6-20). The presentation showed that the performance of the master legs cannot be generalized as assumed by BASt since another leg with the same build level shows a different performance. Mr. Kinsky concluded that industry proposes to stick to the agreements of the TEG regarding the impactor thresholds. Dr. Ries added that for the time being it seems to be more important to get impactors with a stable performance than re-discussing the thresholds that can be used with these impactors.

Mr. Zander required OICA to provide the certification reports of the legform with the different performance to allow an assessment of these data. Mr. Kinsky promised to double-check this and to come back to this (action item A-6-12).

(Note of the secretary: The requested information was provided after the meeting and has been added to the records of this meeting as document GTR9-6-28. Discussion can take place during the next meeting.)

Mr. Nguyen explained that NHTSA for the time being is not yet prepared to accept the currently proposed injury threshold values, especially since the injury risk curves are missing. Both, Mr. Takahashi and Mr. Zander offered to show their injury probability assessments which both are representing different approaches. Mr. Martin clarified that of course the performance thresholds of the impactors have to be agreed but that the question of the injury risk curves is a separate information that is needed to derive the injury risk of the threshold values from and to justify respective rulemaking.

In response to this, Mr. Takahashi presented a document that he had already shown in the 2012 SAE World Congress (document GTR9-6-26; the full paper SAE 2012-01-0277 is available for purchase). He explained that a two-step approach was used in this: In a first step the injury probability functions were developed and then these were double-checked against the data of the EEVC LFI for validation purposes. Mr. Takahashi concluded that finally this process showed equivalent injury probabilities for the FlexPLI and the EEVC LFI, that the bending moment threshold well corresponds to the EEVC LFI’s acceleration and that the MCL elongation is slightly more conservative then the knee bending angle of the EEVC LFI.

Mr. Nguyen appreciated the presentation of Mr. Takahashi and mentioned that NHTSA would welcome to also see similar information for the BASt approach, if possible. However, he also stated that for the time being NHTSA would appreciate to allow contracting parties to the GTR Agreement to use the threshold values a bit flexible, especially when seeing the conflict of the US with the Part 581 requirements.

Mr. Broertjes strongly opposed that flexibility or options should be allowed. Requirements should be set so that all contracting parties can use them. Ms. Chaka pointed out that NHTSA may have also difficulties with the headform test where such flexibility is not provided. Mr. Knotz added that such flexibility then must also be provided for other contracting parties, for example China or India or Russia, if they came up with such a request. However, he doubts that this could work. Mr. Damm added that the presentation of Mr. Takahashi had shown the comparability of the requirements of the FlexPLI with those of the EEVC LFI and that NHTSA had agreed to the original GTR No. 9. Mr. Broertjes supported that therefore this should not be an issue.

Mr. Hardy commented that the data shown by Mr. Takahashi referred to the 1998/2002 EEVC report where in fact 15 degrees were used for the bending angle of the EEVC LFI. The 19 degrees referred to in Mr. Takahashi’s presentation were derived later in the work of TRL for the European Commission when doing the feasibility assessment for the phase 1 of the European requirements. In this study of TRL in 2004, new data from Matsui et al. were included. Mr. Takahashi explained that the Matsui paper contained mistakes. Therefore, the data of a study of Dr. Konosu were used that are correct.

Coming back to document GTR9-6-12, Mr. Zander wondered why the validation of the FlexPLI against vehicle models now should be skipped. Simplified vehicle models could be used for such purposes where the load paths can be modified. This had also been done in other cases in the past. Dr. Konosu and Mr. Takahashi replied that this may be time consuming and that it nevertheless adds variability. Mr. Zander stated that he nevertheless would prefer to have simulation and physical testing against a simplified vehicle model.

Regarding the OICA presentation (see document GTR9-6-20), Mr. Zander stated that the presentation would be erroneous due to some wrong statements. He noted that e.g., as described in GTR9-5-20, the vehicle tests were not used for the proposal to modify the impactor thresholds. Furthermore, he stated that if using the TEG agreed methodology for determining the impactor thresholds, as suggested by GTR9-6-20, e.g. the maximum permissible tibia bending moment would be at 321 Nm.

Mr. Zander then presented the process used by BASt to define the injury criteria and to derive the impactor thresholds in more detail (document GTR9-6-08r1). He pointed out that the BASt approach is based on the same original approach as the Japanese one but was then decided to use different data. However, both approaches lead to injury thresholds and were finally leveled in the Technical Evaluation Group. On request of Mr. Martin Mr. Zander explained that the JASIC approach is not based on tests with the original legform prototypes but the BASt approach does consider these test results at a certain point in the process. After some discussion on this it was agreed that Mr. Zander and Mr. Takahashi will develop a joint document explaining the two approaches to derive the impactor thresholds and especially where the differences are. It was agreed that this should be done by the 1st week of May 2013 (action item A-6-10).

Some discussion then came up on what NHTSA would need for their internal discussion. Mr. Nguyen explained that this has not yet been finally discussed. Dr. Konosu proposed that a schedule should be developed that can be followed to assure that every information is available in time. On request of the chair Mr. Martin promised that NHTSA will review the TEG document that already explained several of the information mentioned above (document TEG-127) and that he will provide some initial comments to Mr. Zander and Mr. Takahashi. As soon as the document of BASt and JASIC is available, NHTSA will review this and submit comments. All other attendees of course are also invited to do so; comments should be made available before 1st July 2013 (action item A-6-11).

Dr. Ries asked to clarify whether this now means that the current impactor thresholds will be maintained. Also, he pointed out again that it is more important to first guarantee a stable performance of the tool itself. The chair responded that by now no decision on this can be made and that this therefore will be decided in the next meeting. Consequently, action item A-4-03 will be postponed to the 7th meeting. Mr. Zander added that for this discussion it would be extremely helpful to get further information about the performance of other legforms on master leg build level as already agreed for action item A-6-06.