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Bone fracture patterns could be crucial in reconstructing the nature of loading, especially in the lower limb and upper limb kinematics in vehicle-pedestrian crashes. In addition, use of FE bone models can be a handy tool to predict vehicle impact velocity and the impact direction. The point of fracture initiation in bone loading has been predicted quite accurately earlier. A methodology that predicts bone crack initiation and its propagation pattern for the six known loading directions using a single material and failure model is presented.
Since 2005, the motorcycle crash fatalities in the US exceeded 10% of the overall annual traffic fatalities. Consequently, it has become critical to gain in-depth understanding of the factors and characteristics contributing to motorcycle crashes. Unfortunately, there currently exists no database gathering the necessary information for an in-depth analysis of the US motorcycle crashes. So this study utilizes the NASS/CDS database (National Automotive Sampling System, Crashworthiness Data System) in order to gain insights into the patterns and factors leading to a NASS/CDS motorcycle crash, from 1997 to 2007. NASS/CDS samples about 5,000 passenger car tow-away crashes per year. Each case includes photographs and detailed data on crash and pre-crash characteristics, vehicle types, trajectories, types of impact, and other pertinent roadway and crash scene information, allowing an in-depth investigation of the crash mechanisms. However, the NASS/CDS sampling process specifically focuses on passenger car crashes, so the cases extracted only correspond to crashes in which a passenger vehicle was towed, and a motorcycle was somehow involved. Thus, a by-hand in-depth review of about 200 cases allowed retrieving 106 relevant crashes for this study, tending to represent the severe passenger vehicle(s) versus motorcycle(s) crashes on US roads. The findings lead to the conclusion that these crashes mostly result from the low conspicuity of the motorcycle, and from the inability of the car drivers to fully appreciate and anticipate the behavior of a motorcycle. Indeed, it has been shown that, first, the car drivers involved in these cases did not attempt any avoidance maneuver, second, they were largely of ages under 25, and finally, the majority of the crashes were in an intersection scenario. In addition, the two major scenarios unveiled were the car attempting a left turn from the opposite direction and the car attempting a left turn from the right. The paper mentions several solutions to enhance the motorcycle- conspicuity and to allow the car drivers to better anticipate its behavior, which seem to be key factors in the intersection-related crashes (and more generally in the passenger vehicle(s) versus motorcycle(s) crashes).
Still correlated with high mortality rates in traffic accidents traumatic aortic ruptures were frequently detected in unprotected car occupants in the early years. This biomechanical analysis investigates the different kinds of injury mechanisms leading to traumatic aortic injuries in todays traffic accidents and how the way of traffic participation affects the frequency of those injuries over the years. Based on GIDAS reported traffic accidents from 1973 to 2014 are analyzed. Results show that traumatic aortic injuries are mainly observed in high-speed accidents with high body deceleration and direct load force to the chest. Mostly chest compression is responsible for the load direction to the cardiac vessels. The main observed load vector is from caudal-ventral and from ventral solely, but also force impact from left and right side and in roll-over events with chest compression lead to traumatic aortic injuries. Classically, the injury appeares at the junction between the well-fixed aortic arch and the pars decendens following a kind of a scoop mechanism, a few cases with a hyperflexion mechanism are also described. In our analysis the deceleration effect alone never led to an aortic rupture. Comparing the past 40 years aortic injuries shift from unprotected car occupants to today's unprotected vulnerable road users like pedestrians, cyclists and motorcyclists. Still the accident characteristics are linked with chest compression force under high speed impact, no seatbelt and direct body impact.
In-depth accident investigation offers many advantages for the analysis and comprehension of crash mechanisms. IFSTTAR makes such investigations since 1992 without interruption. The corresponding database contains more than 1200 accident case studies. Currently, in-depth accident investigation is one of the best ways to determine the speed or cars involved in accidents. This paper first presents the methods used for accident investigation and for accident kinematic reconstruction. Then, in order to illustrate the interest and possible applications of such accident data, it shows some results from a recent study based on the IFSTTAR in-depth accident study programme (IDAS) and dealing with the link between travelling speed and accident risk.
Pedestrian and cyclist are the most vulnerable road users in traffic crashes. One important aspect of this study was the comparable analysis of the exact impact configuration and the resulting injury patterns of pedestrians and cyclists in view of epidemiology. The secondary aim was assessment of head injury risks and kinematics of adult pedestrian and cyclists in primary and secondary impacts and to correlate the injuries related to physical parameters like HIC value, 3ms linear acceleration, and discuss the technical parameter with injuries observed in real-world accidents based documented real accidents of GIDAS and explains the head injuries by simulated load and impact conditions based on PC-Crash and MADYMO. A subsample of n=402 pedestrians and n=940 bicyclists from GIDAS database, Germany was used for preselection, from which 22 pedestrian and 18 cyclist accidents were selected for reconstruction by initially using PC-Crash to calculate impact conditions, such as vehicle impact velocity, vehicle kinematic sequence and throw out distance. The impact conditions then were employed to identify the initial conditions in simulation of MADYMO reconstruction. The results show that cyclists always suffer lower injury outcomes for the same accident severity. Differences in HIC, head relative impact velocity, 3ms linear contiguous acceleration, maximum angular velocity and acceleration, contact force, throwing distance and head contact timing are shown. The differences of landing conditions in secondary impacts of pedestrians and cyclists are also identified. Injury risk curves were generated by logistic regression model for each predicting physical parameters.
Whiplash injuries are characterized by the high variability of its symptoms and by the subjectivity of its diagnosis, which sometimes leads to frauds perpetrated by victims of rear-end impacts. It is estimated that whiplash injuries cost annually about 10.000 million Euros in Europe. Therefore, the aim of this study was to investigate the influence of the dynamics of the accident in which the victim was involved in the probability of development of whiplash associated injuries. In the presented methodology, first an accident reconstruction is performed where the dynamics of the accident is determined. This is carried out using the software PC-Crash, police and insurance companies' data. Then biomechanical injuries criteria related with whiplash injuries are evaluated. For the evaluation of the probability of having whiplash injuries, the Neck Injury Criterion (NIC) of the victim and the mean acceleration of the vehicle were evaluated. Then, with medical reports, the results of the accident reconstruction are correlated with the reported injuries. Some examples are presented. The results obtained indicate that the study of the dynamics of the road accidents in which the victims were involved could be used as an auxiliary of the prognosis of whiplash injuries and is important for a precise diagnosis of this type of injuries.
The incidence of side impacts was investigated from GIDAS data. Both vehicle-fixed object and vehicle-vehicle collisions were analysed as these are enclosed within the consumer testing program. Vehicle-fixed object collisions were stratified according to ESC availability. Results indicated that vehicles equipped with ESC rarely have pure-lateral impacts. An increase in oblique collisions was seen for the vehicles with ESC whereby most vehicle were driving in left curves. The analysis of vehicle-vehicle collisions developed injury risk curves were developed at the AIS3+ injury severity for the vehicle-vehicle side impacts. Results suggested that greatest injury risk occurred when a Pre Euro NCAP vehicle was struck by a Post Euro-NCAP vehicle. The remaining curves did not show different behaviour, indicating that stiffness increased have been equally combated. This was attributable to the few Post Euro-NCAP vehicles that had a deployed curtain airbag available in the sample. The integration of Euro NCAP testing has shown to improve vehicle crashworthiness for pole collisions, as those vehicles with ESC rarely incur lateral impacts.
Description of road traffic related knee injuries in published investigations is very heterogeneous. The purpose of this study was to estimate the risk of knee injuries in real world car impacts in Germany focusing vulnerable road users (pedestrians, bicyclists and motorcyclists) and restrained car drivers. The accident research unit analyses technical and medical data collected shortly after the accident at scene. Two different periods (years 1985-1993 and 1995-2003) were compared focusing on knee injuries (Abbreviated Injury Scale (AISKnee) 2/3). In order to determine the influences type of collision, direction and speed as well as the injury pattern and different injury scores (AIS, MAIS, ISS) were examined. 1.794 pedestrians, 742 motorcyclists, 2.728 bicyclists and 1.116 car drivers were extracted. 2% had serious ligamentous or bony injuries in relation to all injured. The risk of injury is higher for twowheelers than for pedestrians, but knee injury severity is higher for the latter group. Overall the current knee injury risk is low and significant reduced comparing both time periods (27%, p<0,0001). Severe injuries (AISKnee 2/3) were below 1%). Improved aerodynamic design of car fronts reduced the risk for severe knee injuries significantly (p=0,0015). Highest risk of injury is for motorcycle followed by pedestrians, respectively. Knee protectors could prevent injuries by reducing local forces. The classically described dashboard injury was rarely identified. The overall injury risk for knee injuries in road traffic is lower than estimated and reduced comparing both periods. The aerodynamic shape of current cars compared to older types reduced the incidence and severity of knee injuries. Further modification and optimization of the interior and exterior design could be a proper measurement. Classic described injury mechanisms were rarely identified. It seems that the AIS is still underestimating extremity injuries and their long term results.
This study analyses no.39 cases in which n.41 motorcyclists were fatally injured, or 36% of total motorcycle fatalities in Northern Ireland between 2004 and 2010 (n.114). There were n.17 cases (43.6%) where the actions of another vehicle driver caused the collision, in thirteen of these cases the motorcycles had their lights switched on. The remaining n.22 collisions (56.4%) were due to the actions of the motorcyclist. In the approach to the collision scene, there were n.13 cases (31.7%) in which the approach was a right hand bend and in n.8 (19.5%) cases, the approach was a left hand bend. In the remaining n.18 (43.9%) cases, the approach was a straight road. Of the n.17 (41.4%) motorcycles that slid after falling, n.10 (24.4%) fell onto their right side and the remaining n.7 (17.1%) fell onto their left side. The information from this study identifies primary and contributory causes of motorcycle collisions.
Rollovers continue to be a major source of heavy truck fatalities when compared to other accident modes. Real world rollover accidents are analyzed and two distinct damage patterns are identified. Damage to heavy truck roofs can occur from lateral loading that transitions to vertical roof loading as the vehicle rolls onto its side and then over onto its roof. A second load path can occur when the vehicle has rolled onto its side and furrows into the ground generating large longitudinal friction forces between the roof and ground. A review of the previous literature and various test methodologies are presented. A sled impact test methodology is presented which allows for structural assessment of a heavy truck cab's crashworthiness in both of these loading environments. Two test series are presented using the sled impact test methodology in order to analyze real world truck rollovers using varying impact platen and contact angles. The structural deformation and failure patterns were found to be consistent with damage seen in real world accident vehicles. In each case, a second equivalent truck cab was then reinforced and tested under similar conditions to evaluate the energy management and crush resistance of a stronger cab structure. These structural reinforcements demonstrated a substantial reduction in roof crush and protected the survival space of the occupant compartment. The sled impact test procedure is an effective method for testing the structural performance of a heavy truck cab in a variety of loading scenarios comparable to real world accidents and ascertaining the load and energy load levels in these accident modes.