When a child is struck by a car, what factor determines the area of greatest injury?

The area of greatest injury when a child is struck by a car is largely influenced by the size of the child and the height of the bumper upon impact. When a vehicle strikes a child, the height of the bumper plays a critical role in determining which parts of the child's body are most likely to be impacted. Since children are often shorter than adults, the location of a car's bumper can align strikingly with critical areas of a child's body, such as the abdomen and head, which can lead to severe injuries.

Considering the other options, while the speed of the vehicle and the child's height are relevant factors in assessing the severity of injury, they do not specifically focus on the relationship between the child's dimensions and the vehicle's design features. The interaction of these elements—size and height—directly correlates with the anatomical vulnerability of children during such incidents, making the combination of the child's size and the bumper height the most significant in predicting potential injury patterns.