Why are infants placed in rear-facing safety seats?
The first thing is, we're concerned about a crash that comes from the front. We always worry about that because those are the most common and serious collisions. Since in a collision, everything moves toward the point of impact, you're not thrown away from crashes, you move toward them. So, in a frontal crash, everyone goes toward the front. If you understand how a safety seat works, you can see that a rear-facing seat is going to cushion the entire body against the whole shell of the seat. Therefore, that's the safest way to ride. If you're in a forward facing seat, and you've got that top tether attached (which helps to hold the child's head and back farther back from the point of impact) that's another safe way to ride. When you're in a booster seat, you're going to move into the shoulder lap belt. You'll probably move perhaps a little farther than if you're in a tethered seat, although boosters are tested, but you might have a little more looseness in the safety belt than what we would recommend. Also, with a booster seat, there is less around the child to absorb crash forces, particularly because a lot of impacts are not directly frontal or directly from the side. Again, if you think about a side impact, the child in the rear facing seat is more enclosed, and the seat will turn a little bit toward the side. You have more protection. So, it has been shown that riding rear-faced in a car is the best way to ride.
