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Vehicle traffic accidents have been extensively studied in various countries, but any differences in traffic accidents the studied areas have not yet been adequately investigated. This paper aims to make a comparison study of head injury risks and kinematics of adult pedestrian accidents in Changsha, China, and Hannover, Germany, as well as correlate calculated physical parameters with injuries observed in real-world accidents of the two cities. A total of 20 passenger cars versus adult pedestrian accidents were collected from the two areas of study, including 10 cases from Changsha and 10 cases from Hannover. Virtual accident reconstructions using PC-Crash and MADYMO software were performed. The in-depth study focused on head injury risks while kinematics were conducted using statistical approaches. The results of the analysis of the Chinese data were compared with those of the German data.

Lower limb injuries are common result of car to pedestrian impacts. A reversible bumper system was developed to reduce the risk of such injuries. In order to improve the protective performance of the bumper system, it was necessary to investigate the efficiency of the bumper system at different impact conditions and design configurations. In this study, the protective performance of the reversible bumper system was assessed by finite element (FE) modeling of lower limb impacts. The FE model of a production car front was developed and validated. The FE model of the reversible bumper system was then developed and replaced the original bumper in the car front model. A human lower limb FE model was used to evaluate the protective performance of the reversible bumper system. The effects of the bumper design parameters on protective performance were investigated by using the statistical method of factorial experiment design.

Head injury is quite frequently occurred in car-to-pedestrian collisions, which often places an enormous burden to victims and society. To address head protection and understand the head injury mechanisms, in-depth accident investigation and accident reconstructions were conducted. A total of 6 passenger-cars to adult-pedestrian accidents were sampled from the in-depth accident investigation in Changsha China. Accidents were firstly reconstructed by using Multi-bodies (MBS) pedestrian and car models. The head impact conditions such as head impact velocity; position and orientation were calculated from MBS reconstructions, which were then employed to set the initial conditions in the simulation of a head model striking a windshield using Finite Element (FE) head and windshield models. The intracranial pressure and stress distribution of the FE head model were calculated and correlated with the injury outcomes.

The objective of this study was to evaluate the performance of various configurations of a driver restraint system by using a combined injury criteria index and making the restraint system adaptive to different frontal crash coinditions, such as severity of the crash, belt use, sitting position, pre-impact braking and size of the driver. For this purpose, a mathematical model of a driver restraint system was developed. The study was divided into three steps: 1. A FE-model of the driver airbag was developed by using MADYMO 3D program; 2. The model was validated by comparing the simulations to crash tests; 3. Effects of design changes in an adaptive restraint system on injury parameters were investigated in simulations of frontal car impacts. It was found that the performance of the restraint system was most influenced by the size of the ventilation hole and the capacity of the gas generator.

This paper presented a part of results from an ongoing project for pedestrian protection, which is carried out at Chalmers University of Technology in Sweden. A validated pedestrian mathematical model was used in this study to simulate vehicle-pedestrian impacts. A large number of simulations have been carried out with various parameters. The injury-related parameters concerning head, chest, pelvis and lower extremities were calculated to evaluate the effect of impact speed and vehicle front structure on the risk of pedestrian injuries. The effect of following vehicle parameters was studied: stiffness of bumper, hood edge, hood top, windscreen frame, and shape of vehicle front structures. A parameter study was conducted by modelling vehicle-pedestrian impacts with various sizes of cars, mini vans, and light trucks. This choice represents the trends of new vehicle fleet and their frequency of involvement in real world accidents.

Pedestrians are a high-risk group in vehicle impacts, especially in urban areas. In Europe pedestrians account for around 20 % of all traffic fatalities. In the rest of the world this frequency varies from 14 % in USA up to 47% in Thailand. The majority of pedestrian fatalities are due to head impacts. Today’s cars are very densely packed under the bonnet. Certain stiff parts, such as the spring tower and the top of the engine, are very close to the bonnet. There is often not enough space for bonnet deformation by an impacting head. The consequence is often a severe or fatal head injury. Therefore, a protection system has been developed to decrease the severity of head-to-bonnet impacts. The system is activated at the impact by a sensor located in the bumper, at speeds above 20 km/h. The sensor is able to discriminate objects with a different geometry (another car versus a leg), as well as with a different stiffness (a pole versus a leg).

The shearing and bending injury mechanisms of the knee joint are recognised as two important injury mechanisms associated with car-pedestrian crash accidents. A study on shearing and bending response of the knee joint to a lateral impact loading was conducted with a 3D multibody system model of the lower extremity. The model consists of foot, leg and thigh with concentrated upper body mass. The body elements are connected by joints, including an anatomical knee joint unit that consists of the femur condyles, tibia condyles and tibia1 intercondylar eminence as well as ligaments. The biomechanical properties of the model were derived from literature data. The model was used to simulate two series of previously performed experiments with lower extremity specimens at lateral impact speeds of 15 and 20 km/h.

A 3D pedestrian knee joint model was developed as a first step in a new description of the whole pedestrian body for computer simulations. The model was made to achieve better correlation with the results from previous tests with biological material. The model of the knee joint includes the articular surfaces, ligaments and capsule represented by the ellipsoid and plane elements as well as the spring-damping elements, respectively. The mechanical properties of the knee joint were based on available biomechanical data. To verify the new developed model with results from tests with biological material previously performed at the Department of Injury Prevention, Chalmers University of Technology, the computer simulations were carried out with the model of the knee joint using the MADYMO 3D program.