A prospective study of children aged <16 years in motor vehicle collisions in Norway: severe injuries are observed predominantly in older children and are associated with restraint misuse.

•All severe motor vehicle collisions (MVCs) involving child passengers that occurred in south-eastern Norway during a 39-month period (2009–2013) were studied.•Consent to study the details of the child passengers was received for 100 of the 106 MVCs that occurred during the observation period.•No child deaths occurred, and 27 children sustained injuries with AIS 2+ injuries.•Safety errors were detected for 14 of the 15 children (93%) with AIS scores of 3+.•Safety errors were observed for all 10 children sustaining abdominal AIS 2+ injuries.•Incorrect routing or adjustment of seat belts and unsecured objects in the boot or passenger compartment were common safety errors.