A kinematic analysis of the head-neck unit has been conducted in 37 simulated traffic accidents in order to investigate correlations between neck response and injuries. Belted fresh human cadavers in the age range 18 to 74 years have been used as front and rear-seat passengers.
The analysed data included 23 frontal collisions, impact velocity 30 km/h, 50 km/h and 60 km/h , barrier impact and 14 90°-car to car lateral collisions with near-side passengers (6 cases) as well as far-side rear-seat passengers with an in-board upper anchoring point for the shoulder belt (8 cases).
The head bending angle depended on the type of the collision. At the frontal collision, the mean head bending maxima amounted 79°, the evaluated mean angular velocity maxima and angular acceleration maxima corresponded to 41 rad/s and 2208 rad/s², the mean maximum velocity in trajectory of the head was 10 m/s, the mean maximum acceleration along the path amounted 23 g.
With the same collision velocity of 50 km/h in the 90°-car to car lateral collision higher mean values of head bending angle maxima were observed in the near-side front passengers (62°) than in the far-side rear-seat passengers (57°). The evaluated angular velocity maxima and angular acceleration maxima amounted in the mean for the near-side passengers 43 rad/s and 2887 rad/s², the mean maximum velocity in trajectory of the head amounted 8 m/s, the mean maximum acceleration along the path was 33 g; for the far-side passengers the mean angular velocity maxima of 26 rad/s were evaluated, for the angular acceleration it was 1345 rad/s², for the head velocity in trajectory 10 m/s and for the acceleration along the path 18 g.
Injuries of AIS 1 (hemorrhage = strain) already occurred at an angular acceleration of 560 rad/s² or a head acceleration of 13 g along the path, whereas the cervical spine may remain uninjured at an angular acceleration of still 2470 rad/s² or head acceleration of 23 g along the path. On the other hand, an AIS 3 was observed at an angular acceleration of 1320 rad/s² or a head acceleration of 22 g along the path, and an AIS 4 of 49 10 rad/s² or a head acceleration of 39 g along the path.