Here's the stuff I've saved to my computer for quick reference for RFing info, Mostly from around here
The American Academy of Pediatrics recommends rear-facing for as long as possible (to the limits of a convertible seat) for the best protection, which would be to 30-35 lbs. OR when the head is 1-inch from the top of the carseat.
http://babyproducts.about.com/od/carseats/qt/rear_facing.htm
According to NHTSA, a rear-facing car seat is 71 percent safer than no restraint at all, and a forward-facing car seat is 54 percent safer than no restraint at all.
When a child is forward-facing, there is a lot of stress put on his/her neck in a crash. The weight of a child's head in a crash causes the spinal column to stretch...the spinal cord, however, is NOT meant to stretch! This can cause a tear...which means paralysis or even death. This is referred to as "internal decapitation"...the child's head would be slumped forward and it would look as though he/she was sleeping. It doesn't matter if the child has great head control...that means nothing. New data is showing that a forward-facing child is 4 times more likely to be seriously injured or killed than a rear-facing child of the same age.
(note: having a carseat that allows tethering RFing reduces this risk (only two brands on the market currently allow this feature, Britax and Sunshine kids). New carseats can almost always can be tethered FFing which reduces head excursion in an accident. Even older cars can be retrofitted to add Top Tether Anchors)
Rear-facing seats do such a great job of protecting children because the back of the carseat absorbs the crash forces. The child's head, neck, and spine are kept in alignment, allowing the carseat to absorb the forces. The child's head is also kept contained in the carseat, decreasing the risk of coming into contact with projectiles.
More Rear Facing Information
1) rear-end collisions are less frequent than front-end collisions
2) rear-end collisions statistically occur at much lower impact speeds than front-end collisions
3) side impact collisions are less dangerous when RFing because of the way the carseat rotates in a side-impact collision.
4.) A forward-facing child under 2 years old is 4 times MORE likely to be killed or seriously injured in a crash and that the American Academy of Pediatrics recommends rear-facing for as long as possible for the best protection and that there has never been a single reported case of hip/leg/foot injury from rear-facing.
5.)What about big babies? A 95th percentile baby may look stronger than his 5th percentile friend, but in a crash the bigger baby is likely MORE at risk if he's riding forward-facing. The rigidity of bones and the strength of ligaments in the spine is likely the same in children of the same age, no matter their size. And a 95th percentile baby likely has a much larger, heavier head, which will pull forward which much more force than that of a 5th percentile child.
http://www.freewebs.com/sacredjourneys/newbornpreschool.htm, You can see that a child's head is a fourth of their body as a baby and you can also see how the bones calcify and harden as they get older.
6.) Many parents in the US think it's "weird" to have a 2 year old rear-facing--most children are switched to forward-facing around their first birthday. But if you lived in Sweden, the idea of a 2 year old FORWARD-facing would be "weird," as they keep kids rear-facing until the ages of 3 or 5. In Sweden, children go straight from rear-facing seats to booster seats! Because kids sit rear-facing for so long, fewer than 1 child a year dies in a rear-facing car seat in Sweden. If we also kept more kids rear-facing, we would not only see fewer deaths, but also fewer injuries--especially the really hard to fix ones like those to the spinal cord and head.
http://www.msnbc.msn.com/id/9916868/
http://www.thecarseatlady.com/car_seats/rear-facing_seats.html