I am borrowing this from my friend Amy over at Family Journeys with Twins....
This is why I am planning to keep Charlotte rear-facing for as long as we can! :) We worked too hard to get her here safely to lose her over something so silly as her legs might be a little squished. So, until she reaches 35lbs, the weight limit for our convertible seat, she will be rear-facing!
The American Academy of Pediatrics recommends rear-facing for as long as possible for the best protection. This means that children should rear-face to the maximum limits of a convertible carseat...which is 30-35 lbs. (depending on the seat) OR when his/her head is 1-inch from the top of the carseat shell. The rule that most parents know is that children must rear-face to at least 1 year AND 20 lbs. (the child must be BOTH 1 year and 20 lbs., not either or). What is not well known is that 1 year AND 20 lbs. is the bare minimum and it is strongly recommended that they be kept rear-facing for much longer.
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! The spinal column can stretch up to 2 inches but the spinal cord can only stretch up to 1/4 inch before it snaps, 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. 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.
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.
Something I hear often is "His legs are scrunched up, he must be uncomfortable" or "Won't his legs be injured that way?". There has NEVER been a single reported case of hip/leg/foot injury from extended rear-facing. Even if there were...a broken leg is much better than a broken neck.
Children are much more flexible than adults, so what may be uncomfortable for us, is not for a child. If you watch a child playing, you will notice that they choose to fold their legs up...they don't sit with them straight out or hanging over the edge of the couch. My boys fold their legs up in the stroller and squat or sit with their legs underneath them when playing quite often. They have never once complained about being uncomfortable in their carseats...never...the just fold their legs, hang them over the sides, or prop them up on the seatback. That is comfortable to a child.
Just the other day, when we got into the car, my 3 year old got in his brother's seat (rear-facing) and refused to get out. I asked him several times if he was sure he wanted to ride that way and he said yes. After being forward-facing for almost 3 months, he chose to sit rear-facing again and didn't complain once. He's hovering around the rear-facing weight limit though, so I did turn his seat back around forward-facing today.
As far as being harnessed as long as possible, think race car drivers. They wear 5 pt. harnesses, not just seatbelts. A 5 pt harness is much safer in side-impacts and rollovers, which tend to be very serious/deadly crashes. Most children outgrow their carseats (most go to 40 lbs.) before they are truly ready for a booster. The bare minimum for a booster is 4 years and 40 lbs...a child should be in a 5 pt. harness until then and even longer if possible.
Even at 4 years and 40 lbs, a child should only be moved to a booster if he or she can sit in it properly for the entire trip, every trip. It is extremely important for the belt to fit properly and stay in place (lap belt as low as possible, touching thighs, and shoulder belt between neck and shoulder).
The 5-Step Test.
1. Does the child sit all the way back against the auto seat?
2. Do the child's knees bend comfortably at the edge of the auto seat?
3. Does the belt cross the shoulder between the neck and arm?
4. Is the lap belt as low as possible, touching the thighs?
5. Can the child stay seated like this for the whole trip?
If the answer is no to ANY of those questions, the child needs a booster seat. A 4-8 year old child in a booster seat is 59% less likely to be injured in a crash than a child of the same age wearing a seatbelt alone. On a side note, a booster must always be used with a lap/shoulder belt and it is also important than any person riding in just a seatbelt wear a lap/shoulder belt, not a lap belt only.
You can't control how others drive...accidents happen, it's just a fact of life. So why not keep our children as safe as we possibly can...that is one thing we CAN control. If I am in an accident, I know that I've done everything I can to make my babies as safe as they can be in the car. I know that any injury they have will not be because I did not protect them and I can live with that!"