The UK Co-operative Crash Injury Study currently includes data on 205 seat belted drivers from frontal impacts in which an air bag deployed; of these, 142 suffered some degree of injury. To detect the influence of frontal air bags, the distribution of injury over the body regions of these drivers was compared to that of a much larger group from vehicles without air bags. The injured drivers from air bag vehicles showed relatively fewer head injuries, especially fractures, and relatively more arm injuries. No abnormal types of injury or circumstances of injury were identified for the air bag group. Air bags generally appear to deploy at vehicle impact severities that pose a statistical risk of significant head injury, and also in a proportion of lower severity impacts. As a group, the air bag equipped vehicles were larger, more modem, and more often fitted with seat belt pretensioners than the non air bag vehicles, with an older and more male driving population.