Head postures during naturalistic driving.

Drivers use larger and longer duration head movements when stationary than when driving. Given an increased risk of whiplash injury for initially rotated head postures, these findings provide a possible explanation for why drivers are more likely to be injured when hit from behind while their vehicle is stationary. Further, the head postures characterized in this study can be used as initial conditions in volunteer and computational studies to improve our understanding of why nonneutral head postures are associated with increased whiplash injury risk.