Evidence-based justification for extended rear-facing
Updated January 2022
It’s all the rage among parents nowadays: extended rear-facing. If you’re turning your child to face forward before they’ve reached the limits of their carseat, then you’re old-schooling it and increasing your child’s risk of injury in a crash. Many pediatricians still hold onto the now ancient recommendation of turning kids forward-facing at age 1 and 20 lbs., even though their own professional organization, the American Academy of Pediatrics, hasn’t recommended that since before 2002. You were probably in grade school then.
Why is it so critical for kids to stay rear-facing?
When you use the carseat right, it protects them and you from potentially being forever changed if you get into a crash.
Simple Physics Lesson
A carseat will always move toward the point of impact (Newton’s 1st Law). In a frontal collision—at 53.5%, statistically the most common type of severe/fatal crash—the entire back of a rear-facing carseat will protect the head, neck, and spine of a child as it rotates down toward the front of the vehicle. Even in a side impact, which is a more serious type of crash due to its proximity to passengers, there is usually an element of frontal movement, such as a vehicle moving forward through an intersection, as it’s hit from the side. So a rear-facing carseat will rotate down and forward, then toward the side where the impact occurs.
Click each graphic to see the motion:
Compare this to a forward-facing child in a harnessed carseat. In a frontal crash, the carseat still rotates down and forward toward the front of the vehicle, and the child will be flung forward into the harness and forward of the carseat shell. In a side impact, again the carseat rotates down and forward toward the front of the vehicle; the child comes forward into the harness and out of the carseat shell and there is rotation toward the vehicle door where the impact occurs. Because the harness is holding only the shoulders and hips, the head, arms, and legs are flung violently forward. If the harness is loose, which is one of the most common mistakes a caregiver makes, there’s a high likelihood of the child hitting the vehicle seat in front or the side pillar.
Anatomy 101
The folklore is that a child’s neck muscles aren’t developed enough to keep a baby’s neck safe in a car crash, which is why they have to face the rear of the vehicle. I suppose that’s true in a way: it does take babies time to develop their musculature so they can hold their heads up to keep their airways open. But the muscles don’t protect the fragile spinal cord, which is the bundle of nerve fibers that forms the central nervous system and is connected to the brainstem. No amount of baby push-ups will strengthen your child’s muscles to the point of protecting his spinal cord.
The bones of the spinal column are what actually protect the spinal cord and in infants and young children; they aren’t completely fused together for years. One of the most important cervical bones, the Atlas (C1), is what attaches the head to the spinal column. Drawings show where it ossifies, or fuses, at varying times: the anterior arch fuses around age 7, while the posterior neural arches fuse around age 3. Before it fuses, the Atlas and Axis (C2), the 2nd vertebra that the Atlas nestles into, are made of bone and cartilage, which is very pliable. These two vertebrae are held in place by ligaments, which are very elastic (lax) to allow the child to grow.
Studies of infant cadavers have shown that vertebral columns can stretch up to 2” but that the spinal cord is damaged after only ¼”. Given that a baby’s head accounts for ¼ of its total body size versus 1/7 an adult’s size, plus the immaturity of its vertebrae and laxity of the ligaments holding those vertebrae together, rear-facing seems the obvious choice.
The child’s large head shifts the fulcrum of movement—where the head swings forward—higher, elongating the spinal column and potentially causing catastrophic damage to the spinal cord. Before age 8, this fulcrum is in the upper cervical spine, at C2-C3. After age 8, the fulcrum shifts down to C5-C6, where it stays into adulthood. When you hear the term “internal decapitation,” it encompasses this movement of the upper cervical spine since the head swinging forward must happen in order for the ligaments to stretch and pull the head from the Atlas.
Another devastating injury that doesn’t show up on x-ray is called Spinal Cord Injury without Radiographic Abnormality (SCIWORA). This is when the spinal cord stretches because of the elasticity of the ligaments and cartilage in the spinal column. An x-ray will show normal bone alignment and no fractures, but the spinal cord may be irreversibly damaged. Remember that this bundle of fibers can only stretch up to ¼” before having catastrophic damage.
The evidence is clear. Rear-facing carseats protect the most fragile part of a developing child’s body: the head and spinal column. The 2018 American Academy of Pediatrics Policy Statement recommends rear-facing to the weight or height limits of the child’s carseat and instructs their pediatricians to counsel parents about rear-facing at each health visit. The National Highway Traffic Safety Administration (NHTSA) recommends rear-facing as long as possible.
Favorite Links
The American Academy of Pediatrics (AAP) has recommended since 2002 that after age 1 and 20 lbs., children should ride in a rear-facing convertible seat until reaching the weight limit of that carseat. They amended that policy in August 2018 to recommend rear-facing to the weight or height limits of the carseat.
Note how the legs fly away from the back of the vehicle seat during the rear-facing test on the left. In the forward-facing seat, the properly secured dummy bends nearly in half during the crash test. Photo courtesy Kathy Weber, ret., UMTRI, and SafetyBeltSafe USA.
2018 AAP Policy Statement on Child Passenger Safety, includes table summary of best practice recommendations and algorithm chart
2018 AAP Guidelines: rear-facing as long as possible, up to the limits of the car safety seat; includes virtually all children under 2 years of age and most children up to age 4
2018 AAP Technical Report: summary of evidence supporting best practice recommendations
The above video is a simulation comparing properly restrained 18 mo old models rear-facing to forward-facing in a 35 mph crash from the Children’s Hospital of Philadelphia Center for Research and Prevention (CIRP)
SafetyBeltSafe USA’s opinion on how long children should ride rear-facing. (How Long Should Children Ride Facing the Back of the Car?)
After reviewing studies from the U.S. and Sweden, a study published in the highly regarded British Medical Journal advises keeping children rear-facing until age 4. (www.bmj.com/cgi/content/full/338/jun11_2/b1994?view=long&pmid=19520728)
Leg injuries account for 28% of significant injuries faced by forward-facing children in crashes (Jermakian, J.S., et al. “Lower Extremity Injuries in Children Seated in Forward Facing Child Restraint Systems.” Traffic Injury Prevention 8 (2007): 171-179.)
This analysis shows how leg injuries are common among forward-facing children (Bennett, T.D., et al. “Crash Analysis of Lower Extremity Injuries in Children Restrained in Forward-facing Car Seats During Front and Rear Impacts.” Journal of TRAUMA® Injury, Infection, and Critical Care 2006;61:592-597
A tightly installed rear-facing carseat allows the vehicle and carseat to absorb crash forces and increases “ride down,” the amount of time it takes a body to come to a stop in a crash. The longer the ride down time, the less chance of injury. (http://www.car-safety.org/rearface.html)
Since there is almost always an element of forward motion in a side impact—such as when a vehicle is going straight through an intersection when it is struck on the side by a red-light runner—a rear-facing seat does a better job of keeping a child’s head contained within the safety of the seat. (http://carseatsite.com/whyrearfacing)
Evenflo is now requiring that children be age 2 before forward-facing in their convertible and combination carseats.
Approximately 75% of kids in Sweden rear-face until at least age 4. From 1999-2006, only 4 rear-facing children under age 4 were killed in crashes and their deaths were due to circumstances unrelated to the direction the carseat was facing (fire, drowning, excessive intrusion). During that same timeframe, 6 kids under age 4 facing forward in booster seats were killed; 3 of these crashes were potentially survivable crashes had the children been in rear-facing carseats. (http://www.bmj.com/cgi/content/full/338/jun11_2/b1994)
Anecdotal evidence suggests that infants around ages 10 mos.-18 mos. enter a fussy stage that makes it difficult to put them into any carseat, rear- or forward-facing. Many parents prematurely switch the rear-facing carseat forward-facing thinking that the child is objecting to riding rear-facing, when the child is objecting to being restrained at all. Visit the Car Seat Safety forums at www.car-seat.org and you’ll hear from other experienced parents regarding this phase.
The above video shows how the dummy stays contained in the seat during a rear-facing crash test. The tape on the dummy’s head is for measurement and doesn’t affect its head during the test.
This video is the companion video to the one above and shows a side view of the crash test. Note how little the head moves.
The above video shows a properly installed forward-facing seat. Note the seat belt stretch and how far forward the dummy bends.
The above video from Norway shows the differences between rear- and forward-facing carseats in an animated crash.
The above video from the Buckle Up With Brutus at The Ohio State University demonstrates the difference between rear-facing and forward-facing in crash tests.
If you need more convincing, take it from Dr. Marilyn Bull, a noted pediatrician from one of the country’s best pediatric hospitals, Riley Children’s Hospital in Indiana. This video was produced for, and used in, the current Child Passenger Safety Technician course.
Vehicle crashes are the number 1 killer of children. Protect your children to the best of your ability. Follow best practice.
My kid just hit 44″, which is the max height for rear-facing in our Diono Rainier. Do you know of a seat that would allow us to keep rear-facing?
Elizabeth, any of the Graco convertible carseats on our Recommended Carseats List will work, as will the Britax Boulevard and Advocate ClickTight convertibles, and the Nuna Rava. https://carseatblog.com/safest-recommended-car-seats/
You mention that front end collisions are the most common. The latest statistics from NHTSA actually show approximately 40% of the 6 million car accidents are rear end collisions. In my mind, being in a rear-facing car seat while the rear of the car is hit is equivalent to facing forward in a front end collision. Could it be more risky to face the rear during the most common car collision? Any insight would be greatly appreciated. Thank you.
Hi Philip, thank you for catching that. We forgot to include the emphasis that frontal impacts dominate *severe* crashes, such as those that involving at least one fatal injury in the NHTSA FARS database. Rear-enders generally account for less than 10% of these crashes, depending on the year and study used. Rear-end crashes are much more common at lower speeds, where injuries tend to be whiplash related. Unlike head-on crashes with both vehicles traveling at higher speeds, rear-enders tend to involved a stopped vehicle and a vehicle that is coming to a stop. The forces involved are almost always significantly lower. That is why we generally advise that rear-facing is the safest way to transport children. This is also why the NHTSA and IIHS conduct numerous frontal and side impact crashes in their vehicle safety ratings, but do not conduct any rear-end crash tests at all. (Federal requirements do have a pass/fail rear impact standard, mostly for fuel system integrity).
Even though less common, there is still concern about higher speed rear-end crashes, as well as very high speed frontal crashes that can cause rear-facing carseats to exhibit significant “rebound” following the initial pulse from the crash. This motion would be similar in some respects to what would be seen with a forward-facing carseat in a frontal crash, though still less energetic. Even so, Canada has recently required anti-rebound features to reduce this risk, and such features are also included or available on various rear-facing carseats in the USA. For example, Clek and Britax have anti-rebound bars included with some models, while Diono has a tether that can be used rear-facing to reduce this motion.
http://www.iihs.org/iihs/topics/t/general-statistics/fatalityfacts/passenger-vehicles
The information presented in the article is awesome. Some of the photos depict unsafe care seat practices though. Such as the after market car seat cover in one. There is also one where the straps are not tight enough. Please try to be a little more mindful of the pictures you attach to your articles and make sure they show correct and safe car seat practices. Thank you.
Hi Amanda. You must be talking about the Ashley Floral cover in the first pic. That’s a legitimate Britax cover from eons ago that they had for the Marathon. As for Kecia’s sleeping son, his harness was tight enough, but he had shifted in his sleep so that it looked loose. I wouldn’t have used the pic if she hadn’t assured me beforehand that he was safe. Thanks for reading!
I am a huge advocate for car seat safety!!! This is a great demonstration on why it’s so important to keep them rear facing for as long as possible! I have shared this link with friends and family and on Facebook to help educate people with young children. Thank you for sharing this with everyone, it is so important to keep our babies safe as possible!
For all of the parents worrying about leg injuries–isn’t it more important to protect your child’s neck? Leg bones are much stronger than neck bones, and they can be fixed, whereas a neck cannot. An impact strong enough to break a leg is strong enough to break a neck. Even if you don’t believe the statistics indicating that rear facing children are not more likely to injur their legs, isn’t it still more prudent to protect against the most severe and potentially fatal type of injury?
Love it! It’s great to have the commentary along with the wonderful rearface videos in one article. Great job!
I think people who question whether a tether or latch system was used in the FFing crash tests are missing the point. It’s the force of the head moving forward that’s dangerous, and no car seat is equipped with a head strap! Remember your high school physics class, and that whole bit about inertia? It doesn’t matter whether the car seat is tethered, latched, whatever – it’s the HEAD and LIMBS continuing to move when the car’s forward motion is abruptly slowed that creates the force on the child’s neck. RFing car seats prevent that from happening and absorb that force, which is esp. important for infants and toddlers whose heads are so large in relation to their bodies, and necks are comparatively weak. The forces in a rear-end collision tend to be lower and are distributed differently thru the vehicle, making RFing safe for those crashes as well.
Thanks for putting this together. We are RFing our 2nd child much longer – live and learn! I wish our laws would change to protect more children.
The head excursion relative to the vehicle seat is very much related to the performance of the child safety seat and how well it is coupled to the vehicle through the seatbelt or LATCH system. When front facing, that performance is almost always improved with a tether. The less head excursion, the less risk that the head strikes a hard interior feature of the vehicle. There is no doubt that rear-facing is a safer mode of travel, especially for babies and toddlers that cannot as easily withstand the forces on the neck and spine in a front facing child seat. Later, as a child’s body matures, the skeletal and connective tissues can withstand these forces better and the main risk becomes that of a direct impact to the head. Properly installed and used, front-facing seats provide a great deal of protection, too.