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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).