Final answer:
Head injuries are the most common cause of traumatic death in infants and children.
Step-by-step explanation:
The most common cause of traumatic death in infants and children, according to the information provided, is head injuries. These injuries can occur as a result of falls, automobile and motorcycle accidents, or physical abuse such as shaken-baby syndrome. Head injuries account for approximately 30 percent of all injury-related deaths in the United States, making them a significant cause of traumatic death in this age group.