Various research studies performed at different institutes (Deutscher 1994, Geigl et al 1994) have shown that current car seats are by no means optimized regarding the protection of occupants during rear end impacts. Sled tests performed with volunteers and PMTO’s (Geigl et al, 1994) have shown some weak points of selected seats. In order to obtain more information on problems within the construction of current car seats, a comparison of standard seats seemed to be important.
In a collaboration between Graz University of Technology and the VdS (Verband der Schadenversicherer, Munich) approx. 7500 rear end impacts with personal injuries were investigated. The data was taken from the "Vehicle Safety 90" (VdS, 1994) a statistic which contains 15,000 actual car to car accidents with at least one occupant injured during 1990 in Germany (old states only). From these investigations several factors which influence neck injuries in rear end collisions could be evaluated.
On the other hand sled tests with volunteers were performed for some selected car seats. The head-neck kinematics of the occupants was measured and visualized. Identical test conditions as far as possible have been chosen in repeated tests to ensure a fair comparison of the different tests. Nine different types of car seats were used at sled impact velocities of 8 and 11 km/h. The mean sled decelerations were settled at a level of 2.5 g.
The comparison of the statistics with the measurements showed a fair correlation between both approaches. So a "ranking" of the different seats regarding their risk of a neck injury during rear end impacts could be defined and the biggest problems in seat construction could be summarized.