Effects of Rider Posture on Head Injuries in E-Scooter–Vehicle Collisions

Head injury is one of the most prevalent and severe injury types in collisions between e-scooters and motor vehicles, yet the specific effects of rider posture remain unclear. This study employed MADYMO multi-body dynamics simulations to investigate three rider postures, namely different collision angles, upper-body rotation, and body inclination. Collision models were established for e-scooter–sedan and e-scooter–minivan collisions. The Head Injury Criterion (HIC15) and Brain Injury Criterion (BrIC) were adopted to evaluate the linear and rotational head impact injuries of riders, respectively. A total of 434 simulations were conducted. The results indicate that all three postures exert significant influences on both HIC15 and BrIC. Taking the scenario where the e-scooter is perpendicular to the motor vehicle as the baseline, in minivan collisions, more severe linear and rotational head impact injuries occur when the e-scooter deflects away from the minivan, the rider’s upper body rotates toward the minivan side, and the rider’s body inclines toward the minivan side. For sedan collisions, linear impact injuries follow a similar pattern. Nevertheless, rotational impact injuries become more severe when the rider’s upper body rotates away from the sedan and the rider’s body inclines away from the sedan. These findings contribute to a deeper understanding of the risk patterns of rider head injuries in such collisions and provide a basis for developing mitigation strategies for rider head injuries.