The AAP now recommends that all infants and toddlers should ride in a Rear-Facing Car Safety Seat until they are 2 years of age or until they reach the highest weight or height allowed by their car safety seat’s manufacturer!!
Car Seat Guide 2011 Info for Families:: healthychildren.org
This makes me extremely hapy...as I wholehelartedly believe that the previous "one year or 20lb *recommendation(!!)*" - something most parents seem to consider the rule of absolute maximum, rather than absolute minimum - is just not logical OR safe!! Based on skeletal models of a one-year-old's spine, vs a two or even four-year-old's.. just basic anatomy proves the inconsistency of that previous rule! In the short year between the ages of one and two, there is a *huge* difference in the spine’s development!!! Babies under 3yrs - but ESP under two - have very immature bones and connective tissue, thus creating a particularly serious risk of spinal cord injury in a frontal crash. However, studies haveshown that children who are left to ride RF, are 5x safer in the case of a frontal collision (which according to Crashtest.Com, frontal and frontal offset crashes combine for about 72% of severe crashes. Side impacts are about 24%. Rear and rear offset crashes only account for about 4%!). As they say... "Broken leg -cast it... broken neck -casket."
(Yes, while I admit ^that^ does present as a rather crude mental picture... it certainly makes one think, no?)
One thing I regret most in my parenting journey thus far, is that I didnt fight to keep KB rear-facing (RF) longer! B insisted that we turn her around 16 months... and though I was uncomfortable with the decision (and even had a seat/means to follow through)... I didn't know enough info o on the matter, to be able to back up my instinct and give me a basis to insist otherwise. Thankfully, I have since learned a lot more... and have already begun showing B the research. So if we are blessed with other children, there will be no question as to the protocol we take - Extended-RF all the way!!
More resources on ERF..