How does sitting rear-facing help prevent injury?

In a frontal crash, when everyone moves to the point of impact--the front of the car--a rear-facing baby will move in a different way. A rear-facing baby will move into the back of his car seat and will slide gently up the car seat. This allows the back of the car seat to absorb the brunt of the impact and distribute the remaining forces along the child's entire back, which is the strongest part of his body. The most important part: because he sits rear-facing, the child's head, neck, and torso all move together in a straight line. The whiplash motion is avoided totally.

This photo shows two crash tests of properly installed car seats – one rear-facing and the other forward-facing – in a frontal crash. Note that both dummies are properly secured in the car seats (i.e. the harness straps are snug). The rear-facing dummy’s head and back are cradled by the back of the car seat. The forward-facing dummy’s head and neck are thrown forward in the whiplash motion.

Rear-facing seats also protect children better during side-impact crashes (the most deadly types of crashes). In a side-impact, everyone moves toward the impact. A forward-facing adult or child will pivot around their pelvis and turn to the side, leaving their head at risk for hitting the doorframe, window, other hard structures, etc. When a child is rear-facing in a car seat, the car seat itself does the pivoting, allowing the child's body to stay in a straight line. And since his head usually does not extend beyond the sides of the car seat, his head is better protected.