Sonstige
Filtern
Erscheinungsjahr
Dokumenttyp
- Konferenzveröffentlichung (101) (entfernen)
Schlagworte
- Injury (101) (entfernen)
Institut
Validation of human pedestrian models using laboratory data as well as accident reconstruction
(2007)
Human pedestrian models have been developed and improved continually. This paper shows the latest stage in development and validation of the multibody pedestrian model released with MADYMO. The biofidelity of the multibody pedestrian model has been verified using a range of full pedestrian-vehicle impact tests with a large range in body sizes (16 male, 2 female, standing height 160-192cm, weight 53.5-90kg). The simulation results were objectively correlated to experimental data. Overall, the model predicted the measured response well. In particular the head impact locations were accurately predicted, indicated by global correlation scores over 90%. The correlation score for the bumper forces and accelerations of various body parts was lower (47-64%), which was largely attributed to the limited information available on the vehicle contact characteristics (stiffness, damping, deformation). Also, the effects of the large range in published leg fracture tolerances on the predicted risk to leg fracture by the pedestrian model were evaluated and compared with experimental results. The validated mid-size male model was scaled to a range of body sizes, including children and a female. Typical applications for the pedestrian models are trend studies to evaluate vehicle front ends and accident reconstructions. Results obtained in several studies show that the pedestrian models match pedestrian throw distances and impact locations observed in real accidents. Larger sets of well documented cases can be used to further validate the models especially for specific populations as for instance children. In addition, these cases will be needed to evaluate the injury predictive capability of human models. Ongoing developments include a so-called facet pedestrian model with a more accurate geometry description and a more humanlike spine and neck and a full FE model allowing more detailed injury analysis.
To date, the Trauma Registry (TraumaRegister DGU-® contains data of approximately 100.000 severely injured patients, 65% of which suffered from a road traffic crash. Thus, it is the world's largest data base for severely injured patients. The article describes the development of the registry and explains how it was rolled out over Germany using the established structure of the German Trauma Network (TraumaNetzwerk DGU-®). In addition, this article presents three typical use cases from the fields of quality management, policy making and system-wide interventions, clinical research and injury prevention. In conclusion, the TraumaRegister DGU-® is a well-established tool for various purposes related to the control and reduction of the burden of road injury. Its ongoing expansion to other countries will support the goal of international benchmarking of hospitals and trauma systems.
Police records about traffic accidents like used by IRTAD (International Road Traffic and Accident Database) and CARE (Community Road Accident Database) do not represent all road injuries. For instance, road accidents of bicyclists without a counterpart are usually not reported. Furthermore, IRTAD-like data contains hardly any information on injury outcome and accident circumstances. This information gap leads to an under-representation of the safety concerns of the most vulnerable road users like children and the elderly both in accident research and safety promotion. Injury registration for the European Injury Database (IDB), in turn, combines details of accident causation with diagnostic information that can be used to assess injury severity and long term consequences. The IDB is collecting data from hospital emergency department patients and is being implemented in a growing number of countries. In this article IDB results on mode of transport and injury outcome are presented from a sample of nine EU member states.
A total survey of road traffic accidents involving most severely injured, defined as sustaining a polytrauma or severe monotrauma (ISS > 15) or being killed, was conducted over 14 months in a large study region in Germany. Data on injuries, pre-clinical and clinical care, crash circumstances and vehicle damage were obtained both prospectively and retrospectively from trauma centers, dispatch centers, police and fire departments. 149 patients with a polytrauma and eight with a severe monotrauma were recorded altogether. 22 patients died in hospital. Another 76 victims had deceased at the accident scene. In 2008, 49 % of patients treated with life-threatening injuries were car or van occupants, 21 % motorcyclists, 18 % cyclists and 10 % pedestrians. Among fatalities at the scene, vehicle occupants constituted an even larger portion. The number of road users with life-threatening trauma in the region was extrapolated to the German situation. It suggests that 10 % among the "seriously injured" as defined in national accident statistics are surviving accident victims with a polytrauma or severe monotrauma.
In road traffic accidents, a car-seat and its occupant can be subjected to various crash pulses in the case of a rear impact. This study investigates the influence of crash pulse shape on seat-occupant response and evaluates the corresponding risk of whiplash injury. For this purpose, a rigorously validated seat-occupant system model is used to study different carseat designs and crash pulses. Two different car-seat concepts are also presented which can effectively mitigate whiplash injury for a wide range of crash severity. It is shown that for crash pulses of similar severity, the level of whiplash-risk depends strongly on the combined effects of seat design and crash pulse shape.
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.
Bicyclists are minimally or unprotected road users. Their vulnerability results in a high injury risk despite their relatively low own speed. However, the actual injury situation of bicyclists has not been investigated very well so far. The purpose of this study was to analyze the actual injury situation of bicyclists in Germany to create a basis for effective preventive measures. Technical and medical data were prospectively collected shortly after the accident at the accident scenes and medical institutions providing care for the injured. Data of injured bicyclists from 1985 to 2003 were analyzed for the following parameters: collision opponent, collision type, collision speed (km/h), Abbreviated Injury Scale (AIS), Maximum AIS (MAIS), incidence of polytrauma (Injury Severity Score >16), incidence of death (death before end of first hospital stay). 4,264 injured bicyclists were included. 55% were male and 45% female. The age was grouped to preschool age in 0.9%, 6 to 12 years in 10.8%, 13 to 17 years in 10.4%, 18 to 64 years in 64.7%, and over 64 years in 13.2%. The MAIS was 1 in 78.8%, 2 in 17.0%, 3 in 3.0%, 4 in 0.6%, 5 in 0.4%, and 6 in 0.2%. The incidence of polytrauma was 0.9%, and the incidence of death was 0.5%. The incidence of injuries to different body regions was as follows: head, 47.8%; neck, 5.2%, thorax, 21%; upper extremities, 46.3%; abdomen, 5.8%; pelvis, 11.5%, lower extremities, 62.1%. The accident location was urban in 95.2%, and rural in 4.8%. The accidents happened during daylight in 82.4%, during night in 12.2%, and during dawn/dusk in 5.3%. The road situation was as follows: straight, 27.3%; bend, 3.0%; junction, 32.0%; crossing, 26.4%; gate, 5.9%; others, 5.4%. The collision opponents were cars in 65.8%, trucks in 7.2%, bicycles in 7.4%, standing objects in 8.8%, multiple objects in 4.3%, and others in 6.5%. The collision speed was grouped <31 in 77.9%, 31-50 in 4.9%, 51-70 in 3.7%, and >70 in 1.5%. The helmet use rate was 1.5%. 68% of the registered head injuries were located in the effective helmet protection area. In bicyclists, head and extremities are at high risk for injuries. The helmet use rate is unsatisfactorily low. Remarkably, two thirds of the head injuries could have been prevented by helmets. Accidents are concentrated to crossings, junctions and gates. A significant lower mean injury severity was observed in victims using separate bicycle lanes. These results do strongly support the extension or addition of bicycle lanes and their consequent use. However, the lanes are frequently interrupted at crossings and junctions. This emphasizes also the important endangering of bicyclists coming from crossings, junctions and gates, i.e. all situations in which contact of bicyclists to motorized vehicles is possible. Redesigning junctions and bicycle traffic lanes to minimize the possibility of this dangerous contact would be preventive measures. A more consequent helmet use and use and an extension of bicycle paths for a better separation of bicyclists and motorized vehicle would be simple but very effective preventive measures.
Small overlap frontal crashes are defined by a damage pattern with most of the vehicle deformation concentrated outboard of the main longitudinal structures. These crashes are prominent among frontal crashes resulting in serious and fatal injuries, even among vehicles that perform well in regulatory and consumer information crash tests. One of the critical aspects of understanding these crashes is knowing the crash speeds that cause the types of damage associated with serious injuries. Laboratory crash tests were conducted using 12 vehicles in three small overlap test conditions: pole, vehicle-to-vehicle collinear, and vehicle-to-vehicle oblique (15-degree striking angle). Field reconstruction techniques were used to estimate the delta V for each vehicle, and these results were compared with actual delta V values based on vehicle accelerometer data. Estimated delta Vs were 50% lower than actual values. Velocity change estimates for small overlap frontal crashes in databases such as NASS-CDS significantly underestimate actual values.
The incidence and treatment of sternal fractures among traffic accidents are of increasing importance to ensure best possible outcomes. Analysis of technical indicators of the collision, preclinical and clinical data of patients with sterna fractures from 1985-2004 among 42,055 injured patients were assessed by an Accident Research Unit. Two time groups were categorized: 1985-1994 (A) vs. 1995-2004 (B). 267/42,055 patients (0.64%) suffered a sterna fracture. Regarding the vehicle type, the majority occurred after car accidents in 0.81% (251/31,183 pts), followed by 0.19% (5/2,633pts) driving motorbike, and 0.11% (4/3,258pts) driving a truck. 91% wore a safety belt. Only 13% of all passengers suffering a sternal fracture had an airbag on board (33/255 car/trucks), with an airbag malfunction in 18%. The steering column was deformed in 39%, the steering wheel in 36%. Cars in the recent years were significantly older (7.67-±5 years (B) vs. 5.88-±5 years (A), p=0.003). Cervical spine injuries are frequent (23% vs. 22%), followed by multiple rib fractures (14% vs. 12%) and lung injuries (12% vs. 11%). We found 9/146 (6%) and 3/121 patients (3%) with heart contusion among the 267 sternal fractures. MAIS was 2.56-±1.3 vs. 2.62-±1.3 (A vs. B, p=0.349). 18% of patients were polytraumatized, with 11.2% dying at the scene, 2.3% in the hospital. Sternal fractures occur most often in old cars to seat-belted drivers often without any airbag. Severe multiple rib fractures and lung contusion are concomitant injuries in more than 10% each indicating the severity of the crash. Over a twentyyear period, the injury severity encountered was not different with 18% polytrauma patients suffering sternal fractures.
The bicyclist accidents were analyzed to get better understanding of the occurrences and frequency of the accidents, injury distributions, as well as correlation of injury severity/outcomes with engineering and human factors in two different countries of China and Germany. The accident cases that occurred from 2001 to 2006 were collected from IVAC database in Changsha and GIDAS database in Hannover. Based on specified sampling criteria, 1,570 bicyclist cases were selected from IVAC database in Changsha, and 1806 cases were collected from Hannover, documented in GIDAS database. Statistical analyses were carried out by using these selected data. The results from the statistical analysis are presented and discussed in this study.
To elucidate the risk of pedestrians, bicycle and motorbike users, data of two accident research units from 1999 to 2014 were analysed in regard to demographic data, collision details, preclinical and clinical data using SPSS. 14.295 injured vulnerable road users were included. 92 out of 3610 pedestrians ("P", 2.5%), 90 out of 8307 bicyclists ("B", 1.1%) and 115 out of 4094 motorcycle users ("M", 2.8%) were diagnosed with spinal fractures. Thoracic fractures were most frequent ahead of lumbar and cervical fractures. Car collisions were most frequent mechanism (68, 62 and 36%). MAIS was 3.8, 2.8 and 3.2 for P, B and A with ISS 32, 16 and 23. AIS-head was 2.2, 1.3 and 1.5). Vulnerable road users are at significant risk for spine fractures. These are often associated with severe additional injuries, e.g. the head and a very high overall trauma severity (polytrauma).
Introduction: Spine injuries pose a considerable risk to life and quality of life. The total number of road deaths in developed countries has markedly decreased, e.g. in Germany from over 20000 in 1970 to less than 4000 in 2010, but little is known how this is reflected in the burden of spine fractures of motor vehicle users. In this study, we aimed to show the actual incidence of spine injuries among drivers and front passengers and elucidate possible dependencies between crash mechanisms and types of injuries.
The so-called "seat-belt injuries" or "seat-belt syndromes", described as 2-point seat-belt injuries, contain heavy inflection injuries of the lumbal spinal column, combined with heavy abdominal injuries as rupture of the upper intestinal bold or heavy injuries of the upper entrails. With "playing" children in the font of the car, with inappropriate plant of 3-point belts, identical injuries can occur.
In Germany averagely two million traffic accidents happen each year and emergency medical services are called to more than 400 000 patients. Even though this number is decreasing continuously (due to improvements in the fields of vehicle safety, road construction, and accident prevention) every case is yet a challenge for the rescuers and requires improvements in emergency medicine as well. Especially during diagnostics right at the accident scene, there are only limited instruments available to gain the necessary knowledge of the injuries suffered, to come to essential decisions about treatment or transport. To provide an additional diagnostic aid by scouting and estimating the situation, a software-tool calculating the likeliness of the most frequent severe injuries (AIS 3-6) of front occupants in passenger cars has been developed to deliver this necessary information about particular accident scenarios. To achieve this, logistic likelihood functions have been calculated in a multivariate regression analysis analysing all AIS 3+ injuries in the GIDAS database of the years 1999-2006 that happened more than four times
In most of developed countries, the progress made in passive safety during the last three decades allowed to drastically reduce the number of killed and severely injured especially for occupants of passenger cars. This reduction is mainly observed for frontal impacts for which the AIS3+ injuries has been reduced about 52% for drivers and 38% for front passengers. The stiffening of the cars' structure coupled with the generalization of airbags and the improvement of the seatbelt restraint (load limiter, pretension, etc.) allowed to protect vital body regions such as head, neck and thorax. However, the abdomen did not take advantage with so much success of this progress. The objective of this study is to draw up an inventory on the abdominal injuries of the belted car occupants involved in frontal impact, to present adapted counter-measures and to assess their potential effectiveness. In the first part the stakes corresponding to the abdominal injuries will be defined according to types of impact, seat location, occupants' age and type of injured organs. Then, we shall focus on the abdominal injury risk curves for adults involved in frontal impact and on the comparisons of the average risks according to the seat location. In the second part we will list counter-measures and we shall calculate their effectiveness. The method of case control will be used in order to estimate odds ratio, comparing two samples, given by occupants having or not having the studied safety system. For this study, two type of data sources are used: national road injured accident census and retrospective in-depth accident data collection. Abdominal injuries are mainly observed in frontal impact (52%). Fatal or severe abdominal occupant- injuries are observed at least in 27% of cases, ranking this body region as the most injured just after the thorax (51%). In spite of a twice lower occupation rate in the back seats compared to the front seats, the number of persons sustaining abdominal injuries at the rear place is higher than in the front place. In recent cars, the risk of having a serious or fatal abdominal injury in a frontal impact is 1.6% for the driver, 3.6% for the front passenger and 6.3% for the rear occupants. The most frequently hurt organs are the small intestine (17%), the spleen (16%) and the liver (13%). The most common countermeasures have a good efficiency in the reduction of the abdominal injuries for the adults: the stiffness of the structure of the seats allows decreasing the abdominal injury risk from 54% (driver) to 60% (front occupant), the seatbelt pretensioners decrease also this risk from 90% (driver) to 83% (front passenger).
This work aims at bringing evidence for mass incompatibility in frontal impact for cars built according to the UNECE R94 regulation. French national injury accidents database census for years 2005 to 2008 were used for the analysis. The heterogeneity of frontal self-protection among cars of different masses is investigated, as well as the partner protection parameter offered by these cars. The last part of the analysis deals with the estimation of the benefit, in terms of fatal and severe injuries avoided, if crashworthiness was harmonized for the whole fleet of vehicle. This calculation is done for France and is extended to all Europe.
While cyclists and pedestrians are known to be at significant risk for severe injuries when exposed to road traffic accidents (RTAs) involving trucks, little is known about RTA injury risk for truck drivers. The objective of this study is to analyze the injury severity in truck drivers following RTAs. Between 1999 and 2008 the Hannover Medical School Accident Research Unit prospectively documented 43,000 RTAs involving 582 trucks. Injury severity including the abbreviated injury scale (AIS) and the maximum abbreviated injury scale (MAIS) were analyzed. Technical parameters (e.g. delta-v, direction of impact), the location of accident, and its dependency on the road type were also taken into consideration. The results show that the safety of truck drivers is assured by their vehicles, the consequence being that the risk of becoming injured is likely to be low. However, the legs especially are at high risk for severe injuries during RTAs. This probability increases in the instance of a collision with another truck. Nevertheless, in RTAs involving trucks and regular passenger vehicles, the other party is in higher risk of injury.
A reduction of around 48% of all road fatalities was achieved in Europe in the past years including a reduced number of fatalities with an older age. However, among all road fatalities, the proportion of elderly is steadily increasing. In an ageing society, the European (Horizon2020) project SENIORS aims to improve the safe mobility of older road users, who have different transportation habits compared to other age groups. To increase their level of safe mobility by determining appropriate requirements for vehicle safety systems, the characteristics of current road traffic collisions involving the elderly and the injuries that they sustain need to be understood in detail. Hereby, the paper focuses on their traffic participation as pedestrian, cyclist or passenger car occupant. Following a literature review, several national and international crash databases and hospital statistics have been analysed to determine the body regions most frequently and severely injured, specific injuries sustained and types of crashes involved, always comparing older road users (65 years and more) with mid-aged road users (25-64 years). The most important crash scenarios were highlighted. The data sources included European statistics from CARE, data on national level from Germany, Sweden, Italy, United Kingdom and Spain as well as in-depth crash information from GIDAS (Germany), RAIDS (UK), CIREN and NASS-CDS (US). In addition, familiar hospital data from Germany (TraumaRegister DGU-®), Italy (Italian Register of Acute Traumas) and UK hospital statistics (TARN) were included in the study to gain further insight into specific injury patterns. Comprehensive data analyses were performed showing injury patterns of older road users in crashes. When comparing with mid-aged road users, all databases showed that the thorax body region is of particularly high importance for the older car occupant with injury severities of AIS 2 or AIS 3+, whereas the body regions lower extremities, head and thorax need to be considered for the older pedestrians and cyclists. Besides these comparisons, the most frequent and severe top 5 injuries were highlighted per road user group. Further, the most important crash configurations were identified and injury risk functions are provided per age group and road user group. Although several databases have been analysed, the picture on the road safety situation of older road users in Europe was not complete, as only Western European data was available. The linkage between crash data and hospital data could only be made on a general level as their inclusion criteria were quite different.
Supported by field accident data and monitoring results of European Regulation (EC) No. 78/2009, recent plans of the European Commission regarding a way forward to improve passive safety of vulnerable road users include, amongst other things, an extension of the head test area. The inclusion of passive cyclist safety is also being considered by Euro NCAP. Although passenger car to cyclist collisions are often severe and have a significant share within the accident statistics, cyclists are neither considered sufficiently in the legislative nor in the consumer ratings tests. Therefore, a test procedure to assess the protection potential of vehicle fronts in a collision with cyclists has been developed within a current research project. For this purpose, the existing pedestrian head impact test procedures were modified in order to include boundary conditions relevant for cyclists as the second big group of vulnerable road users. Based on an in-depth analysis of passenger car to cyclist accidents in Germany the three most representative accident constellations have been initially defined. The development of the test procedure itself was based on corresponding simulations with representative vehicle and bicycle models. In addition to different cyclist heights, reaching from a 6-year-old child to a 95%-male, also four pedal positions were considered. By reconstruction of a real accident the defined simulation parameters could be validated in advance. The conducted accident kinematics analysis shows for a large portion of the constellations an increased head impact area, which can reach beyond the roof leading edge, as well as high average values for head impact velocity and angle. Based on the simulation data obtained for the different vehicle models, cyclist-specific test parameters for impactor tests have been derived, which have been further examined in the course of head and leg impact tests. In order to study the cyclist accident kinematics under real test conditions, different full scale tests with a Polar-II dummy positioned on a bicycle have been conducted. Overall, the tests showed a good correlation with the simulations and support the defined boundary test conditions. Typical accident scenarios and simulations reveal higher head impact locations, angles and velocities. An extended head impact area with modified test parameters will contribute to an improved protection of vulnerable road users including cyclists. However, due to significantly differing impact kinematics and postures between the lower extremities of pedestrians and cyclists, these injuries cannot be addressed by the means of current test tools such as the flexible pedestrian legform impactor FlexPLI. Based on the findings obtained within the project as well as the existing pedestrian protection requirements a cyclist protection test procedure for use in legislation and consumer test programmes has been developed, whose requirements have been transferred into a corresponding test specification. This specification provides common head test boundary conditions for pedestrians and cyclists, whereby the existing requirements are modified and two parallel test procedures are avoided.
Real world accident reconstruction with the Total Human Model for Safety (THUMS) in Pam-Crash
(2013)
Further improvement of vehicle safety needs detailed analysis of real world accidents. According to GIDAS (German In-Depth Accident Study) most car to car front accidents occur at mid-crash severity. In this range thoracic injuries already occur. In this study a real world frontal crash with mid-crash severity out of the AARU database was reconstructed. The selected car to car accident was reconstructed by AARU by means of pc-crash software in order to get the initial dynamic accident conditions. These initial conditions were used to reconstruct the complete accident in more detail using FE models for the car structure and the occupants. Occupant simulations were performed with FE HIII-dummy models and the THUMS using Pam-Crash code. An initial THUMS validation was performed in order to verify the model-´s biofidelity by means of table-top test simulations. THUMS bone stiffness values were modified to match the real word occupant age. A comparison between driver and passenger restraint system loading was done, as well as an injury prediction comparison between the HIII-dummy model and THUMS response for both cases. Detailed comparison between the HIII-dummy models and THUMS regarding thoracic loading are discussed.