A primary function of pedestrian dummies is biofidelic representation of whole body kinematics. To assess the biofidelity of a pedestrian dummy, corridors for the kinematic response of post-mortem human surrogates (PMHS) tested in full-scale pedestrian impact tests were developed. Three PMHS were tested in full-scale pedestrian impact tests using a late-model small sedan with an impact velocity of 40 km/h. Three additional tests using the Polar-II dummy were conducted in identical conditions to those used in the PMHS tests.
All impacts were conducted with the PMHS or dummy positioned laterally at the center line of the vehicle, in a mid-stance gait position, with the struck-side limb positioned posteriorly and the upper limbs placed anterior to the torso. Initially supported by a harness, each surrogate was released prior to impact and was unconstrained through a 250 ms interaction with the vehicle.
Using photo targets mounted at the equivalent locations of the head center of gravity (CG), top of the thorax, thorax CG, and pelvis CG, the kinematic response of the pedestrian surrogates was evaluated using parametric trajectory data. To account for simultaneous variability in multiple kinematic parameters, boxed-corridors based on a percentage of trajectory path length were developed from the trajectory data. Given the significance of head impact for pedestrian injury outcome, head velocity-time corridors were also developed.
Comparing dummy response and PMHS corridors, the Polar-II generally replicated the complex kinematics of the PMHS and demonstrated good overall biofidelity. Greater sliding up the hood by the PMHS, and lack of neck muscle tension in the PMHS have been identified as potential causes for differences in the length and shape of body segment trajectories. More testing is necessary to assess the effects differences in pre-test orientation, surrogate stature, and clothing will have on surrogate response.