Pedestrian disability and fatality as a consequence of car crashes is a large global health problem. A new doctoral thesis from Karolinska Institutet now shows that upper-body collision with the car's lower windscreen is a common cause of severe injuries and deaths in adults, especially in those accidents where the head is struck. Children injured by cars are mostly hit by the hood.
To introduce maximally effective car-based countermeasures it is important to understand which injuries are most common and from which car parts they originate. It is also important to focus on the most severe injuries resulting in disability or death. The aim of the current thesis, presented by Rikard Fredriksson at the Department of Public Health Sciences, was therefore to determine priorities for and evaluate the potential of car-mounted safety systems designed to mitigate severe upper-body injuries (including disability and fatality) of pedestrians in car crashes.
Accident data was collected from two areas: Severe accidents in Dresden/Hannover in Germany and fatal accidents in Sweden. Experimental head-to-hood component tests with succeeding brain simulations were performed to evaluate the influence of the under-hood distance and head impact speed. The results shows amongst other things, that 31% of the injured pedestrians sustained a permanent impairment of some kind and 5% sustained a more severe impairment, where the head was most susceptible to severe impairment.
The car front frequently caused leg injuries, which is addressed in current European regulations. However, current legal tests do not address the most common upper-body injury source, the windshield, which was found to be the dominating cause of head injuries. Chest injuries, frequently caused by both the hood and windshield areas in the severe and fatal crashes in this thesis, are also unaddressed in legal tests.
Children are most commonly head-injured from the hood area, which is addressed in current regulations. Further, regulations do not fully consider brain injury with the current head test methods. Therefore, in this thesis focus was on upper-body injury/source combinations not addressed in the regulations, that is, the head-to-windshield area and chest-to-hood/windshield areas, and the evaluation of brain injury in hood and windshield impacts.
Rikard Fredriksson is a researcher at the safety company Autoliv, which also funded his thesis.
Priorities and Potential of Pedestrian Protection - Accident Data, Experimental Tests and Numerical Simulations of Car-to-Pedestrian Impacts, ISBN: 978-91-7457-242-1. publications.ki.se/jspui/handle/10616/40465