Babies should be in rear-facing car seats for at least one year and until they weigh at least 20 pounds, but that's really a minimum standard. Extended rear-facing, beyond one year and 20 pounds, has big safety advantages that parents should consider.
You've probably heard the one year/20 pounds advice from many sources, including your pediatrician, the car seat company and possibly your state's car seat law. Let's take a look at the reasons for keeping babies rear-facing in car seats, why you should never turn baby around early, and some reasons why you might want to delay the big turnaround.
Why Rear-Facing? Car seats are designed to absorb some crash forces and spread remaining crash forces over a larger area of the body. For adults, seat belts distribute the bulk of the force to the strongest parts of the body, the hips and shoulders.
Infants don't have body parts that are strong enough to withstand crash forces, so the rear-facing car seat distributes the crash force along the entire back, neck and head, putting less stress on one part of the body. The infant's head, which is large and heavy for a still delicate neck to support, is also better supported with a rear-facing car seat. The incidence of severe head and neck injuries for babies is greatly reduced in rear-facing car seats. The baby's "ride-down time," or the time it takes to come to a complete stop, is also lengthened, which reduces injuries by reducing the body trauma from a sudden stop.
The additional support plus the manner in which a rear-facing car seat "rides down" in a crash gives your baby the best chance for survival and less chance of injury in a crash. The simple way to estimate crash force is weight times speed. So a 10-pound baby in a 30 mph crash would experience 300 pounds of force. A rear-facing car seat spreads that 300 pounds of force over a greater body area, causing less injury to the baby.
My Baby Wants to Be Front-Facing! Even if your baby's legs are touching the seat back, or the baby cries when rear-facing, you should still keep baby rear-facing to at least one year and 20 pounds. Both requirements must be met before turning baby around. An 18-pound 14-month-old baby should rear-face because her body is not big enough to tolerate crash forces in a forward-facing car seat. Likewise, a 25-pound 10-month-old should remain rear-facing because his neck is not sufficiently developed to handle the crash forces while in a forward-facing car seat.
Many parents worry that their baby will suffer broken legs in a crash because baby's legs touch the seat back or look cramped when rear-facing. It's important to remember, though, that in a crash severe enough to break baby's legs, there would also be enough force to cause severe neck injuries if your young baby was forward-facing. While it's never fun to choose between injuries, the chance of full recovery is greater for broken legs than broken necks. Similarly, if your baby fusses while in a rear-facing car seat, it may seem easy to turn baby around to keep him or her happy. Again, though, you're choosing between a fussing baby or the chance of severe head, neck and spine injuries.
My Baby is One Year Old and 20 Pounds! Now What? Technically, it's OK to turn your baby around now, but before you do, consider the safety benefits of extended rear-facing. Car seat safety advocates, along with the National Highway Traffic Safety Administration (NHTSA) and the Academy of Pediatrics (AAP) now recommend that babies stay in a rear-facing car seat to the weight limit of the seat, or as long as possible. If your baby's car seat has a rear-facing weight limit of 30 pounds, these groups say you should keep baby rear-facing to 30 pounds. Some car seats have rear-facing weight limits up to 35 pounds, which can accomodate the average child through age 2 and maybe beyond. You should also check the manufacturer's rear-facing height limit to be sure baby is not too tall to safely stay rear-facing to the weight limit.
Why would you want to keep your child rear-facing? Crash data shows us that anybody is safer in a crash when riding rear-facing for the reasons we outlined above. Even though your baby's neck is now strong enough to withstand the forward-facing crash forces, he or she is still better protected in a rear-facing car seat because that seat still distributes the force over a greater body area and still gives better support to their young head and neck.
A forward-facing car seat is safe after one year AND 20 pounds, but a rear-facing car seat is safer. 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. Keeping your baby rear-facing to the limit of the seat is the safest choice. You can check your car seat instruction book or the labels on the car seat sides to find the rear-facing weight and height limits.
Heather Corley is a NHTSA-certified Child Passenger Safety Technician.