Many motor vehicle occupants are at increased risk of injury due to physical differences that affect their interaction with the vehicle interior and restraints as well as their response and tolerance to crash loading. Older occupants may sustain more severe injuries due to weaker bones and calcified tissues. Occupant shape, which is associated with body mass index, can lead to suboptimal restraint fit. Vulnerable occupant research is underway to identify the unique challenges of protecting all motor vehicle occupants:
    • Older Occupants
    • Obesity
      Obesity has been shown to affect injury risk in crashes. This study examines the effects of body mass index on seat belt fit by measuring belt fit in a laboratory study of 54 men and women. The results suggest obesity introduces effective slack into the seat belt by routing the belt further away from the skeleton, which may affect injury risk due to more severe contacts with the interior and “submarining” in frontal crashes.

    • Child Occupants
    • Unattended Children