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This study is aimed to investigate the correlations of impact conditions and dynamic responses with the injuries and injury severity of child pedestrians by accident reconstruction. For this purpose, the pedestrian accident cases were selected from Sweden and Germany with detailed information about injuries, accident cars, and accident environment. The selected accident cases were reconstructed using mathematical models of pedestrian and passenger car. The pedestrian models were generated based on the height, weight, and age of the pedestrian involved in accidents. The car models were built up based on the corresponding accident car. The impact speeds in simulations were defined based on the reported data. The calculated physical quantities were analyzed to find the correlation with injury outcomes registered in the accident database. The reconstruction approaches are discussed in terms of data collection, estimating vehicle impact speeds, pedestrian moving speeds and initial posture, secondary ground impact, validity of the mathematical models, as well as impact biomechanics.
At the 2005 ESV conference, the International Harmonisation of Research Activities (IHRA) side impact working group proposed a 4 part draft test procedure, to form the basis of harmonisation of regulation world-wide and to help advances in car occupant protection. This paper presents the work performed by a European Commission 6th framework project, called APROSYS, an further development and evaluation of the proposed procedure from a European perspective. The 4 parts of the proposed procedure are: - A Mobile Deformable Barrier test; - An oblique Pole side impact test; - Interior headform tests; - Side Out of Position (OOP) tests. Full scale test and modelling work to develop the Advanced European Mobile Deformable Barrier (AE-MDB) further is described, resulting in a recommendation to revise the barrier face to include a bumper beam element. An evaluation of oblique and perpendicular pole tests was made from tests and numerical simulations using ES-2 and WorldSID 50th percentile dummies. It was concluded that an oblique pole test is feasible but that a perpendicular test would be preferable for Europe. The interior headform test protocol was evaluated to assess its repeatability and reproducibility and to solve issues such as the head impact angle and limitation zones. Recommendations for updates to the test protocol are made. Out-of-position (OOP) tests applicable for the European situation were performed, which included additional tests with Child Restraint Systems (CRS) which use is mandatory in Europe. It was concluded that the proposed IHRA OOP tests do cover the worst case situations, but the current test protocol is not ready for regulatory use.
Aim of the study was to evaluate the protective effect of bicycle helmets particularly considering injuries to the head and to the face. Accidents with the participation of bicyclists which occurred from 2000 to 2007 were chosen from GIDAS. We observed that injuries to the head and face were more severe in the group of non-helmeted riders. There seems to be no significant difference in injuries with AIS 3-6. Altogether 26 cyclists were killed. 2 of them wore a helmet (1% of helmeted cyclists), 24 did not (1% of non-helmeted cyclists). Only one killed rider (without helmet) did not suffer from polytrauma (only head injuries recorded). The findings seem to support the thesis of a preventive effect of the bicycle helmet, however the two groups are different in their characteristics related to riding speed. Necessarily we need a multivariate model to evaluate the effect of helmets.
Cycle helmets have continued to increase in popularity since their introduction half a century ago. Many studies indicate that overall, head injury can be significantly reduced by wearing them. This study was conducted using two distinct sets of real-world cycling collision data from Ireland, namely cases involving police collision reports and cases involving admission to a hospital emergency department. The analyses sought to simulate and analyse the protective performance of cycle helmets in such collision scenarios, by comparing the Head Injury Criterion score and peak head accelerations, both linear and angular. Cycle collisions were simulated using the specialised commercial software MADYMO. From the simulation results, these key metrics were compared between the same-scenario helmeted and unhelmeted cyclist models. Results showed that the inclusion of bicycle helmets reduced linear accelerations very significantly, but also increased angular accelerations significantly compared to unhelmeted situations. Given the modest protective performance of cycle helmets against angular accelerations, it is recommended that cycle helmet manufacturers and international test standards need to pay more attention to head angular accelerations.
When the EEVC proposed the full-scale side impact test procedure, it recommended that consideration should be given to an interior headform test in addition. This was to evaluate areas of contact not assessed by the dummy. EEVC Working Group 13 has been researching the parameters of a possible European headform test procedure in four phases. Earlier stages of the research have been presented at previous ESV conferences. The conclusions from these have suggested that the US free motion headform should be used in any European test procedure and that it should be a free flight test, not guided. This research has now culminated in proposals for a European test procedure. This paper presents the proposed EEVC side impact interior headform test procedure, giving the rationale for the test and the first results from the validation phase of the test protocol.
Automotive interiors have long been a potentially injurious impact area to occupants during accidents, especially in the absence of adequate padding. The U.S. Federal Motor Vehicle Safety Standard (FMVSS) 201, Occupant Protection in Interior Impact, outlines test procedures and performance criteria in order to mitigate potentially injurious head impacts to interior surfaces. FMVSS 201 specifies a finite set of impact locations and applies to passenger vehicles of a specified year range and with a gross vehicle weight rating less than 10,000 lb. In this paper, two head impact test methodologies are presented, a pendulum-test device and a Free Motion Headform (FMH) launching device, which allows for dynamic, repeatable impact evaluation of various vehicle interior surfaces and their impact attenuation abilities. The presented testing includes multiple series that evaluate the effect of differing vehicle upper interior padding on occupant head injury. One study in particular, analyzes a head impact to the side header of a heavy truck (not included in FMVSS 201) during a 90 degree rollover. Additionally, two other series of tests are presented which assess the injury reduction effect of side airbags to near side as well as far side occupants in a side impact scenario. Lastly, a forensic analysis is presented which evaluates two possible head impact locations experienced in a real world accident by analysis of the resulting interior compartment damage utilizing the FMH launching device test method. The data collected and presented includes accelerometer instrumentation and high speed video analysis. These studies demonstrate that adequate padding and airbags are very effective at mitigating head injury potential at impact speeds of 12-25 mph (19-40 kph).
Evaluation of the performance of competitive headforms as test tools for interior headform testing
(2009)
The European Research Project APROSYS has evaluated the interior headform test procedure developed by EEVC WG 13, representing the head contact in the car during a lateral impact. One important aspect within this test procedure was the selection of an appropriate impactor. The WG13 procedure currently uses the Free Motion Headform as used within the FMVSS 201. The ACEA 3.5 kg headform used in Phase 1 of the European Directive and the future European Regulation on Pedestrian Protection is still discussed as a possible alternative. This paper reports work performed by the Federal Highway Research Institute (BASt) as a part of the APROSYS Task 1.1.3. The study compares the two headform impactors according to FMVSS and ACEA, in a series of basic tests in order to evaluate their sensitivity towards different impact angles, impact accuracy, the effect of differences to impactors of the same type and the effects of the repeatability and reproducibility of the test results. The test surface consisted of a steel tube covered with PU foam and PVC, representing the car interior to be tested. Despite of the higher mass of the FMH the HIC values of this impactor were generally lower than those of the ACEA headform. The FMH showed a higher repeatability of test results but a high sensitivity on the angle of roll, the spherical ACEA impactor performed better with regards to the reproducibility. In case of the ACEA impactor-, the angle of roll had no influence.
This study aimed at comparing head Wrap Around Distance (WAD) of Vulnerable Road User (VRU) obtained from the German in-depth Accident Database (GIDAS), the China in-depth Accident Database (CIDAS) and the Japanese in-depth Accident Database (ITARDA micro). Cumulative distribution of WAD of pedestrian and cyclist were obtained for each database (AIS2+) showing that WAD of cyclists were larger than the ones of pedestrians. Comparing three regions, the 50%tile WAD of GIDAS was larger than that of both Asian accident databases. Using linear regression that might predict WAD of pedestrians and cyclists from Impact speed and VRU height, WADs were calculated to be 206cm/219cm (Pedestrian/Cyclist) for GIDAS, 170cm/192cm for CIDAS and 211cm/235cm for ITARDA. In addition, this study may be helpful for reconsideration of WAD measurement alignment between accident reconstruction and test procedures.
Within the COST Action TU1101 the working group WG 1 is dealing with acceptance criteria and problems in helmet use while bicycling concerning conspicuity, thermal stress, ventilation deficits and other potential confounding. To analyze the helmet usage practice of bicyclists in Europe a questionnaire was developed in the scope of working group 1 to collect relevant information by means of a field study. The questionnaire consists of some 66 questions covering the fields of personal data of the cyclist, riding und helmet usage habits, information concerning the helmet model and the sensation of the helmet, as well as information on previous bicycle accidents. A second complementary study is conducted to analyze if the use of a bicycle helmet influences the seating geometry and the posture of cyclists when riding a bicycle and if the if the helmet vertically limits the vision. For this purpose cyclists with and without helmets were photographed in real world situations and relevant geometrical values such as the decline of the torso, the head posture of the upper vertical vision limit due to the helmet were established from the photos. The interim results of the field studies which were conducted in Germany by the Hannover Medical School are presented in this study. Some 227 questionnaires were filled out, of which 67 participants had used a helmet and 42 of the 227 participants have had a bicycle accident before. For the analysis of the riding position and posture of the cyclist over 40 pictures of riders with a helmet and over 240 pictures of riders without a helmet were measured concerning the seating geometry to describe the influence of using a bicycle helmet. Some results in summary: From the riders interviewed with the questionnaire only 11% of the city bike riders and 12% of the mountain bike riders always used the helmet, while 38% of the racing bike riders and 88% of the e-bike-riders always used the helmet. The helmet use seems not to change the sensation of safety of cycling compared to the use of a car. The arguments for not wearing a helmet are mostly stated to be the short distance of a trip, high temperatures or carelessness and waste of time. The reasons for using a helmet are stated to be the feeling of safety and being used to using a helmet. Being a role model for others was also stated to be a reason for helmet use. Concerning the sensation of the helmet 9% of the riders reported problems with the field of vision when using a helmet, 57% saw the problem of sweating too much, and 10% reported headaches or other unpleasant symptoms like pressure on the forehead when using the helmet. The analysis of the seating posture from the pictures taken of cyclists revealed that older cyclists generally have a riding position where the handle bar is higher than the seat (0-° to 10-° incline from seat to handlebar), while younger riders had a higher variance (between -10-° decline and 20-° incline). Further, elderly riders and riders with helmets seem to have a more upright position of the upper body when cycling. The vertical vision limit due to the helmet is determined by the front rim of the helmet (mostly the sun shade). Typical values here range from 0-° (horizontal line from the eye to the sun shade) to 75-° upwards, in which elderly riders tend to have a slightly higher vertical vision limit possibly due to the helmet being worn more towards the face.
The United Nations Economic Commission for Europe Informal Group on GTR No. 7 Phase 2 are working to define a build level for the BioRID II rear impact (whiplash) crash test dummy that ensures repeatable and reproducible performance in a test procedure that has been proposed for future legislation. This includes the specification of dummy hardware, as well as the development of comprehensive certification procedures for the dummy. This study evaluated whether the dummy build level and certification procedures deliver the desired level of repeatability and reproducibility. A custom-designed laboratory seat was made using the seat base, back, and head restraint from a production car seat to ensure a representative interface with the dummy. The seat back was reinforced for use in multiple tests and the recliner mechanism was replaced by an external spring-damper mechanism. A total of 65 tests were performed with 6 BioRID IIg dummies using the draft GTR No.7 sled pulse and seating procedure. All dummies were subject to the build, maintenance, and certification procedures defined by the Informal Group. The test condition was highly repeatable, with a very repeatable pulse, a well-controlled seat back response, and minimal observed degradation of seat foams. The results showed qualitatively reasonable repeatability and reproducibility for the upper torso and head accelerations, as well as for T1 Fx and upper neck Fx. However, reproducibility was not acceptable for T1 and upper neck Fz or for T1 and upper neck My. The Informal Group has not selected injury or seat assessment criteria for use with BioRID II, so it is not known whether these channels would be used in the regulation. However, the ramping-up behavior of the dummy showed poor reproducibility, which would be expected to affect the reproducibility of dummy measurements in general. Pelvis and spine characteristics were found to significantly influence the dummy measurements for which poor reproducibility was observed. It was also observed that the primary neck response in these tests was flexion, not extension. This correlates well with recent findings from Japan and the United States showing a correlation between neck flexion and injury in accident replication simulations and postmortem human subjects (PMHS) studies, respectively. The present certification tests may not adequately control front cervical spine bumper characteristics, which are important for neck flexion response. The certification sled test also does not include the pelvis and so cannot be used to control pelvis response and does not substantially load the lumbar bumpers and so does not control these parts of the dummy. The stiffness of all spine bumpers and of the pelvis flesh should be much more tightly controlled. It is recommended that a method for certifying the front cervical bumpers should be developed. Recommendations are also made for tighter tolerance on the input parameters for the existing certification tests.