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Within the process of integrating passenger airbags in the vehicle fleet a problem of compatibility between the passenger airbag and rear-facing child restraint systems was recognised. Especially in the US several accidents with children killed by the passenger airbag were recorded. Taking into account these accidents the deactivation of a present passenger airbag is mandatory if a child is carried in a rear-facing child restraint system at the front passenger seat in all member states of the European Union. This rule is in force since the deadline of 2003/20/EC at the latest. In the past a passenger airbag either could not be disabled or could only be disabled by a garage. Today there are a lot of different possibilities for the car driver himself to disable the airbag. Solutions like an on/off-switch or the automatic detection of a child restraint system are mentioned as an example. Taking into account the need for the deactivation of front passenger airbags two types of misuse can occur: transportation of an infant while the airbag is (still) enabled and transportation of an adult, while the airbag is disabled, respectively. Within a research project funded by BASt both options of misuse were analysed utilising two different types of surveys amongst users (field observations and interviews, Internet-questionnaires). In addition both analysis of accident data and crash tests for an updated assessment of the injury risk caused by the front passenger airbag were conducted. Both surveys indicate a low risk of misuse. Most of the misuse cases were observed in older cars, which offer no easy way to disable the airbag. For systems, which detect a child seat automatically, no misuse could be found. The majority of misuses in cars equipped with a manual switch were caused by reasons of oblivion. Also the accident analysis indicates a minor risk of misuse. From more than 300 cases of the GIDAS accident sample that were analysed, only 24 children were using the front passenger seat in cars equipped with a front passenger airbag. In most of these cases the airbag was deactivated. When misuse occurred the injury severity was low. However, when analysing German single accidents the fatality risk caused by the front passenger airbag became obvious. From the technical point of view, there were important changes in the design of passenger airbags in recent years. Not only volume and shape were modified, but also the mounting position of the entire airbag module was changed fundamentally. Even if these findings do not allow obtaining general conclusions, a clear tendency of less danger by airbags could be identified. For future vehicle development a safe combination of airbags and rear faced baby seats seems to be possible in the long term. This would mean that both types of misuse could be eliminated. For parents an easier use of child seat and car would be the result.
In the EC FP6 Integrated Project Advanced Protection Systems, APROSYS, the first WorldSID small female prototype was developed and evaluated by BASt, FTSS, INRETS, TRL and UPM-INSIA during 2006 and 2007. Results were presented at the ESV 2007 conference (Been et al., 2007). With the prototype dummy scoring a biofidelity rating higher than 6.7 out of 10 according to ISO/TR9790, the results were very promising. Also opportunities for further development were identified by the evaluation group. A revised prototype, Revision1, was subsequently developed in the 2007-2008 period to address comments from the evaluation group. The Revision1 dummy includes changes in the half arms and the suit (anthropometry and arm biomechanics), the thorax and abdomen ribs and sternum (rib durability), the abdomen/lumbar area and the lower legs (mass distribution). Also a two-dimensional chest deflection measurement system was developed to measure deflection in both lateral and anterior-posterior direction to improve oblique thorax loading sensitivity. Two Revision1 prototype dummies have now been evaluated by FTSS, TRL, UPM-INSIA and BASt. The updated prototype dummies were subjected to an extensive matrix of biomechanical tests, such as full body pendulum tests and lateral sled impact tests as specified by Wayne State University, Heidelberg University and Medical College of Wisconsin. The results indicated a significant improvement of dummy biofidelity. The overall dummy biofidelity in the ISO rating system has significantly improved from 6.7 to 7.6 on a scale between 0-10. The small female WorldSID has now obtained the same biofidelity rating as the WorldSID mid size male dummy. Also repeatability improved with respect to the prototype. In conclusion the recommended updates were all executed and all successfully contributed in achieving improved performance of the dummy.
The use of proper child restraint systems (CRS) is mandatory for children travelling in cars in most countries of the world. The analysis of the quantity of restrained children shows that more than 90% of the children in Germany are restrained. Looking at the quality of the protection, a large discrepancy between restrained and well protected children can be seen. Two out of three children in Germany are not properly restrained. In addition, considerable difference exists with respect to the technical performance of CRS. For that reason investigations and optimisations on two different topics are necessary: The technical improvement of CRS and the ease of use of CRS. Consideration of the knowledge gained by the comparison of different CRS in crash tests would lead to some improvements of the CRS. But improvement of child safety is not only a technical issue. People should use CRS in the correct way. Misuse and incorrect handling could lead to less safety than correct usage of a poor CRS. For that reason new technical issues are necessary to improve the child safety AND the ease of use. Only the combination of both parts can significantly increase child safety. For the assessment of the safety level of common CRS, frontal and lateral sled tests simulating different severity levels were conducted comparing pairs of CRS which were felt to be good and CRS which were felt to be poor. The safety of some CRS is currently at a high level. All well known products were not damaged in the performed tests. The performance of non-branded CRS was mostly worse than that of the well known products. Although the branded child restraint systems already show a high safety level it is still possible to further improve their technical performance as demonstrated with a baby shell and a harness type CRS.
According to the German road traffic regulations children up to the age of 12 or a height below 150 cm have to use approved and appropriate child restraint systems (CRS). CRS must be approved according to UN-ECE Regulation No. 44. The regulation classifies CRS in 5 weight categories. The upper weight group is approved for children from 22 to 36 kg. However, studies show that already today many children weigh more than 36 kg although they have not reached a height of 150 cm. Therefore, no ECE R44 approved CRS is available for these overweight children. In conclusion, today's sizes and weights of children are no longer represented by the current version of the ECE R44. The heaviest used dummy (P10) weighs just 32.6 kg and has a height of 137.9 cm. Statistical data of German children show that already 5% of the children at a height of 137.9 cm have a weight above 45.3 kg. Regarding children at a height of 145 cm, the 95th percentile limit is at a weight of 53.3 kg. Based on these data 4 dummies with different heights and weights were defined and produced. Two of them are overweight. Up to now, there is no experience how current child restraint systems perform in a car crash if they are used by children with a weight above 36 kg and a height smaller than 150 cm. In the future, different child restraint systems will be tested with respect to the ECE R44 regulation using these overweight dummies.
The main objective of EC CASPER research project is to reduce fatalities and injuries of children travelling in cars. Accidents involving children were investigated, modelling of human being and tools for dummies were advanced, a survey for the diagnosis of child safety was carried out and demands and applications were analysed. From the many research tasks of the CASPER project, the intention of this paper is to address the following: • In-depth investigation of accidents and accident reconstruction. These will provide important points for the injury risk curve, in order to improve it. Different accident investigation teams collected data from real road accidents, involving child car passengers, in five different European countries. Then, a selection of the most appropriate cases for the injury risk curve and the purposes of the project was made for an in-depth analysis. The final stage of this analysis was to conduct an accident reconstruction to validate the results obtained. The in-depth analysis included on-scene accident investigation, creating virtual simulations of the accident/possible reconstruction, and conducting the reconstruction. In the cases of successful reconstructions, new points were introduced to the injury risk curves. Accident reconstructions of selected cases were carried out in test laboratories as the next step following in-depth road accident investigation. These cases were reconstructed using similar child restraint systems (CRS) and the same type make and model as in the real accidents. Reconstructing real cases has several limitations, such as crash angle, cars" approximation paths and crash speed. However, a few changes and applications on the testing conditions were applied to reduce the limitations and improved the representations of the real accidents. After conducting the reconstructions, a comparison between the deformations of the cars on the real accident and the vehicles from the reconstructions was made. Additionally, a correlation between the data captured from the dummies and the injury data from the real accident was sought. This finalises an in-depth analysis of the accident, which will provide new relevant points to the injury risk curve. The CASPER project conducted a large research programme on child safety. On technical points, a promising research area is the developing injury risk curves as a result of in-depth accident investigations and reconstructions. This abstract was written whilst the project was not yet finished and final results are not yet known, but they will be available by the time of the conference. All the works and findings will not necessarily be integrated in the industrial versions of evaluation tools as the CASPER project is a research program.
The European Enhanced Vehicle-safety Committee wants to promote the use of more biofidelic child dummies and biomechanical based tolerance limits in regulatory and consumer testing. This study has investigated the feasibility and potential impact of Q-dummies and new injury criteria for child restraint system assessment in frontal impact. European accident statistics have been reviewed for all ECE-R44 CRS groups. For frontal impact, injury measures are recommended for the head, neck, chest and abdomen. Priority of body segment protection depends on the ECE-R44 group. The Q-dummy family is able to reflect these injuries, because of its biofidelity performance and measurement capabilities for these body segments. Currently, the Q0, Q1, Q1.5, Q3 and Q6 are available representing children of 0, 1, 1.5, 3 and 6 years old. These Q-dummies cover almost all dummy weight groups as defined in ECE-R44. Q10, representing a 10 year-old child, is under development. New child dummy injury criteria are under discussion in EEVC WG12. Therefore, the ECE-R44 criteria are assessed by comparing the existing P-dummies and new Q-dummies in ECE-R44 frontal impact sled tests. In total 300 tests covering 30 CRSs of almost all existing child seat categories are performed by 11 European organizations. From this benchmark study, it is concluded that the performance of the Q-dummy family is good with respect to repeatability of the measurement signals and the durability of the dummies. Applying ECE-R44 criteria, the first impression is that results for P- and Q-dummy are similar. For child seat evaluation the potential merits of the Q-dummy family lie in the extra measurement possibilities of these dummies and in the more biofidelic response.
The GRSP informal group on child restraint systems (CRS) finalised phase 1 of a new regulation for the homologation of CRS . This regulation is the subject of several discussions concerning the safety benefits and the advantages and disadvantages that certain specific points may bring. However, these discussions are sometimes not based on scientific facts and do not consider the whole package but only single items. Based on the experience of the CASPER partners in the fields of human behaviour, accident analysis, test procedures and biomechanics in the area of child safety, a consideration of the safety benefits of phase 1 of the new regulation and recommendations for phase 2 will be given.
Upcoming test procedures and regulations consider the use of Q-dummies. Especially Q6 and Q10 will be introduced to assess the safety of child occupants in vehicle rear seats. Therefore detailed knowledge of these dummies is important to improve safety. As recent studies have shown, chest deflection measurements of both dummies are influenced by parameters like belt geometry. This could lead to a non optimized design of child restraint systems (CRS) and belt systems. The objective of this study is to obtain a more detailed understanding of the sensitivity of chest measurements to restraint parameters and to investigate the possibilities of chest acceleration as an alternative for the assessment of chest injury risks. A study of frontal impact sled tests was performed with Q6 and Q10 in a generic rear seat environment on a bench. Belt parameters like modified belt attachment locations were varied. For the Q6 dummy, different positioning settings of the CRS (booster with backrest) and of the dummy itself were investigated. The Q10 dummy was seated on a booster cushion. Here the position of the upper belt anchorage point was varied. To simulate the influence of vehicle rotation in the ODB crash configuration, the bench was pre-rotated on the sled in additional tests with the Q10. This configuration was tested with and without pretensioner and load limiter. Chest deflection in Q6 showed a high sensitivity to changes in positioning of the CRS and the dummy itself. A more slouched position of the CRS or dummy resulted in a reduction of measured chest deflection, whereas chest acceleration increased for a more slouched position of the CRS. Chest deflection in Q10 is sensitive to belt geometry as already shown in other studies. In a more outboard position of the shoulder belt anchorage the measured chest deflection is higher. Chest acceleration shows the opposite tendency, which is highest for the rearmost location of the upper belt anchorage. On a pre-rotated bench the highest chest deflection within this test series was observed without load limiter/pretensioner and an outboard belt position. By optimizing the belt location and the use of pretensioner/load limier the chest deflection was significantly reduced. For the Q6 a criterion based on chest acceleration as well as deflection measured at two locations might be the most reliable approach, which requires further research with an additional upper deflection sensor. In the Q10 the measured chest deflection does not always correctly reflect the severity of chest loading. The deflection is depending on initial belt position and restraint parameters as well as test conditions, which result in different directions of belt migration. A3ms chest acceleration might be a better indicator for severity of chest loading independent of different conditions like belt geometries. However, in some cases the benefit of an optimized restraint system could only be shown by deflection. These findings suggest that further research is needed to identify a chest injury assessment method, which could be based on deflection as well as acceleration or other parameters related to belt to occupant interaction.
