Data from the National Automotive Sampling System‐Crashworthiness Data System (NASS‐CDS) and the Crash Injury Research Engineering Network (CIREN) cases were analyzed to (1) define how occupant age affects crash exposure and the risk of AIS 3+ injury and (2) identify how age affects injury types and causation while considering comorbid factors and gender. Multivariate logistic regression models developed from NASS indicated that age significantly increases the risk of AIS 3+ injury to almost every body region in all crash modes. The largest age effect was observed for the thorax in frontal crashes and was modulated by gender such that older women were at significantly higher risk relative to younger women than were older men relative to younger men.

A subset of 1289 CIREN cases, analyzed for injury causation, found occupants under age 25 and over 65 years sustained greater proportions of head and thoracic injuries respectively. For frontal crashes, thoracic injury type changed from soft to bony tissue injury as age increased and comorbid factors were more common for the older occupants. Crash severity was consistently lower for the older age groups and outcomes were worse in the older occupants even for similar crash severity and injury.