In the current study, head impacts from real-world moped crashes were analysed to evaluate the influence on injury outcome of different helmet geometries and unfastened chinstraps in primary and ground impacts. Finite element simulations of real-world moped to car crashes were conducted based on technical reports providing initial conditions for two crash scenarios. Finite element helmet models of a full-face and a motocross helmet were generated and validated on the basis of drop test data. The THUMS v4 was equipped with the different helmets and positioned on a moped model. In a parameter study, the influence of helmet type and unfastened chinstrap was evaluated in primary and ground impacts.

The analysis of the different helmet types showed increased neck loadings and relative displacements between head and helmet due to the lever effect of the protruding chinguard of the motocross helmet. All simulations involving a loose chinstrap resulted in helmet loss, consequently leading to increasing the head injury severity in the ground impact.

Both helmet models correlated sufficiently with the reference to drop test data. The parameter study on helmet geometry as well as chinstrap conditions revealed that these factors influence the injury outcome.