Occupant dynamics and injuries in narrow-object side impact

Side impact tree/pole crashes can have devastating consequences. A series of 49 Crash Injury Research and Engineering Network (CIREN) cases of narrow-object side impacts were analyzed. 26 of 49 had serious chest injury and 26 had serious head injury. Of the head trauma patients, 10 had skull fractures, out of which seven were basilar skull fracture. Seventeen of the head trauma patients had some kind of internal bleeding such as subdural or subarachnoid hemorrhage; three were coded as having diffuse axonal injury. Of the chest injuries, 17 occupants had lung contusions and 19 had rib fractures. Of those with rib fractures, 15 of 17 had unilateral rib fractures. Examining crash test data of side pole crashes, it was evident that in tests where the pole caused intrusion at the middle of the occupant’s thigh, a high degree of oblique chest loading occurred. The hypothesis was that this oblique chest loading from the door induces unilateral rib fractures, lung contusions, and possible aortic rupture. Additional testing was done in a sled laboratory to induce oblique chest loading to post mortem human specimens (PMHS). A modified side impact sled buck induced oblique loading at 20 and 30 degree angles to the chest. PMHS subjects experienced unilateral rib fracture patterns. Additional dummy tests in this same configuration were also conducted. Chestband data revealed better biofidelity in the WorldSID dummy than the NHTSA-SID for oblique chest loading. These dummies however, are not currently equipped to measure oblique chest deformations. Narrow-object side impacts are realistic crash environments that can induce oblique chest loading. Because the human may be more vulnerable in this type of crash scenario, dummy biofidelity and measurements, as well as a re-examination of side injury criteria may be necessary to design appropriate injury-mitigating safety devices.