No abstract

As the use of electric self-balancing scooters (ESSs) increases, so does the number of related traffic accidents. Because of the special control method, mechanical structure and driving posture, ESSs are prone to various single-vehicle accidents, such as collisions with fixed obstacles and falls due to mechanical failures. In various ESS accident scenarios, the rider's head injury is the most frequent injury type. In this study, several typical single-ESS accident scenarios are reconstructed via computational methods, and the risk of riders' head/brain injury is assessed in depth using various injury criteria. Results showed that two types of ESSs (solo- and two-wheeler) do not have clear differences in head kinematics and head injury risks; the head kinematics (or falling posture) and ESS accident scenario exhibit a distinct effect on the head injury responses; half of the analysed ESS riders have a 50% probability of skull fracture, a few riders have a 50% risk of abbreviated injury scale (AIS) 4+ brain injury, and none has a diffuse axonal injury; the ESS speed plays an important role in producing the head/brain injury in ESS riders, and generally, higher ESS speed generates higher level of predicted head injury parameters. These findings will provide theoretical support for preventing head injury among ESS riders and data support for developing and legislating ESSs.

Car-to-pedestrian collision (CPC) accidents occur frequently, and pedestrians often suffer serious head/brain injuries. One major cause is the primary impact with the windshield. Here, we use a numerical simulation method to study the influence of the windshield inclination angle of a passenger car on pedestrian head/brain injury due to CPC accidents. The range of the windshield inclination angle was set to 24°–50°, with an interval of 2°. The results show that the windshield angle significantly affects the pedestrian kinematics and exerts different effects on the head injury when evaluating with various head injury criteria. Regarding the head peak linear/rotational acceleration and acceleration-based criteria head injury criterion (HIC)/rotational injury criterion (RIC), the predictions at the secondary impact stage have no clear relationship with the windshield angle (R2 = 0.04, 0.07, 0.03 and 0.26, respectively), and their distributions are scattered. In the primary impact, the peak linear acceleration and HIC show a weak trend of first decreasing and then increasing with the increasing of the windshield angle, and the rotational acceleration and RIC tend to remain relatively constant. Regarding the cumulative strain damage measure (CSDM) criterion, the predictions at the primary impact are slightly lower than those at the secondary impact, and the trend of first decreasing and then increasing with the increase in the windshield angle is observed at both impact stages. When the windshield inclination angle is approximately 32°–40°, the head injury severity in both impact phases is generally lower than that predicted at other windshield angles.