Individual AIS 2+ injuries to the head that occurred to restrained and unrestrained drivers and front seat passengers on the struck side of impacted vehicles were examined. Injury type, injury combination, collision severity in relation to type of injury as well as contact sources were assessed.

47.6% of injuries were AIS 2 level. The most common type of injury was the diffuse brain injury, typically marked by a short period of unconsciousness, which occurred in collisions of lower severity than focal brain and skull fracture injuries.

105 out of 216 (48.6%) of contact sources for all injury types originated from outside the vehicle and such exterior sources were more likely to result in higher level AIS injuries. The most frequent vehicle interior contact source was the side window glass. 30.1% of injuries resulted from head contacts with other vehicles. Diffuse injuries tended to occur independently of other injury types and were more likely to originate from an interior rather than exterior contact.

Preventative measures for head injury reduction in lateral collisions are discussed.