Why Rear-Facing is Safest

A common question asked by parents is, "How soon can I turn my child to face forward?"  The universally accepted response is to keep your child rear facing to AT LEAST one year of age AND 20 pounds in weight.   In fact, it is preferable to keep your child rear-facing as long as possible, and that may mean up to 30 or 35 pounds for most convertible car seats.   The American Academy of Pediatrics and other Child Passenger Safety organizations endorse this philosophy.

Reasons:

Even with best practice, not all injuries can be prevented.   Some crashes are unsurvivable.   Still, much of best practice is based on statistics, and how to have the best chance to reduce injuries. Best practice may also be based on crash forces and physics.   Both are very important regarding the use of rear facing seats.

A few factors govern the physics of crashes as they relate to children in carseats.   Obviously, the faster the vehicles are going, the more energy will be in the crash.  Similarly, heavier vehicles will also have more energy.  Perhaps most important is the length of time passengers have to "ride-down" a crash.   The longer the "ride-down", the more time your skeleton and organs have to absorb the crash energy.   Longer time means less power is transferred to your body, and less chance of injury.

• Statistics.  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%. The NHTSA FARS database shows similar numbers. The odds of being in a frontal crash with a fatality or very serious injury are many times greater than being in a severe rear-end crash. Rear-enders are more common at lower speeds, though most injuries in these crashes are not as severe; typically whiplash injuries to adults, especially passengers lacking proper head restraint.
  
  
• Crash Energy.  Vehicle speed is very important to the energy in a crash, even more important than their weight.  Frontal and frontal offset crashes are the most severe because they often happen with both vehicles traveling at high speeds in opposite directions.
  
  Rear and rear offset crashes, on the other hand, often happen at lower speeds.   In many cases, one vehicle is stopped or nearly stopped, and the other hits it from behind at a relatively low speed.   Other times both vehicles are traveling in the same direction at similar speeds when one is bumped from behind. Either way, the difference in the speed of the vehicles is usually much lower in rear end crashes, and so the energy in the crash will also be much lower.   Lower energy means less chance of injury.
  
  
• Ride-Down Time.  Child Passenger Safety advocates often stress the importance of "Ride-Down Time."  This term simply refers to the time it takes for a person to come to a complete stop in a crash.  This is important because the total force on the passenger increases with both the weight of the person and with the speed they were traveling before the crash.  On the other hand, the total force on the passenger decreases significantly as the time it takes to stop increases.  While we have often have no control of the speeds involved in a crash, we can do some things to help increase the time it takes for a passenger to come to a stop.  As mentioned earlier, in a frontal crash the vehicles are often traveling in opposite directions at high speeds.  When they crash, both vehicles stop very suddenly, in a small fraction of a second.  Even a slight increase in this stopping time can reduce the risk of injury considerably.  This is perhaps the most fundamental concept in keeping passengers alive in a crash.
  
  Take the case of a child in a carseat.  Ideally, you want the child coupled as tightly as possible to the harness system and carseat, and the carseat coupled as tightly as possible to the vehicle with the seatbelt or LATCH system.  When you do this, the child gains all the benefit of "ride-down time" provided by the crushing frame of the vehicle in a crash.  With a loose installation of any kind, the child gets less ride down time and suffers a more severe crash into the harness system.  The analogy is that a tight installation is like catching an egg when you "give" backward with your hand to prevent it from breaking.  A loose installation will be more like holding your arm and hand rigid when you catch the egg.  The egg will splatter in your hand if you don't give, much like what happens to the internal organs of a person when they are flung into a loose seatbelt or harness.  By giving with your arm, you cause the egg to slow down gradually, increasing its ride-down time.  Vehicle frames, advanced seatbelts and airbags are all designed to help passengers slow down more gradually.  Carseats themselves are not designed provide much ride-down time; their main functions are to prevent ejection and to allow the child to be coupled tightly to the vehicle so the frame can provide the necessary ride-down time.
  
  Fortunately, rear-end crashes allow for a lot more ride-down time than frontal crashes.  We already mentioned that the potential energy in a rear-end crash is usually lower than a frontal crash because the speeds involved are slower.  In addition, the two vehicles are not usually moving toward each other like they would be in a frontal crash.  That often means one vehicle is allowed to "give", and the overall ride-down times for both vehicles are much greater, meaning lower forces on the passengers.
  
  
• Forces and Area. We know that frontal and frontal crashes are more frequent, more severe and usually have less ride-down time than rear-end crashes.  In such a frontal crash, it is easy to see why a rear-facing carseat is a better choice.  The entire shell of the carseat cradles the child's back, neck and head. Some seats even have foam protection in the shell to cushion the child even more.  The crash forces are spread throughout the large area of the child's back and head, reducing the pressure during the crash, and keeping the head from snapping backward with respect to the body.  Unlike this rear-facing carseat, a child's legs and head are not restrained at all if they are turned front-facing.  In a serious frontal crash with a front-facing carseat, the head and legs of the child are thrown forward like a rag doll, and serious forces are put on the child's spinal cord.  In a front-facing carseat, only the harness couples the energy to the child's body.  The smaller area of the harness means more pressure on the child.  In the egg analogy, the egg is much less likely to break if it is caught using the whole padded area of your hand rather than with just a couple bony fingers.
  
  Similarly, for the uncommon rear-end crash, a front-facing carseat may be safer than a rear-facing model.  Still, rear-end crashes are much less common and much less severe than frontal crashes, and it is for that reason we choose to maximize the protection for a frontal crash instead.  In addition, rear-facing carseats can also provide an added degree of safety in side-impacts.  Rear-facing seats will usually protect the head from being thrown outside the shell of the carseat much better than a front-facing carseat in a frontal offset or side impact.  Even a minor rear-end crash can be serious for front-facing adults without proper head restraints, but this is usually not an issue for children in properly fitted carseats and boosters.
  
  
• Physiology.  For the reasons listed, rear-facing not only turns out to be safer for infants, but for people of all ages. In fact, we would all be safer rear-facing in cars, airplanes, trains and elsewhere.   Of course, this would not be acceptable to most adults.   Fortunately, adults are somewhat better able to withstand the forces on the head and neck in a severe crash when they are front-facing.   Babies have very immature bones and connective tissue, and this is especially the case when they are younger than 1 year or under 20 pounds.   For that reason, front-facing babies face a particularly serious risk of spinal cord injury in a frontal crash.
  
  

When used properly, rear-facing carseats provide significant safety advantages in frontal, frontal offset and side impacts.  These types of crashes are far more frequent and severe than rear-end crashes.  For these reasons, rear-facing is the safest mode of travel, especially for infants.   In the USA, this recommendation is valid through the 30, 33 or 35 pound maximum rear-facing weight limit of newer convertible carseats, or until the child outgrows their convertible carseat by height.   The height limit of a rear-facing carseat may be listed in the owner's manual.   A child is also considered too tall for a rear-facing seat if the top of their head is at the level of the top of the carseat shell.  It is NOT considered a safety issue if a child's legs are bent at the knees in a rear-facing carseat, or if their feet can touch the vehicle's seat back.   At a very minimum, children should remain rear-facing until AT LEAST one year of age AND 20 pounds in weight.   In countries like Sweden, children are often kept rear-facing much longer, even to 3 or 4 years old.   Auto related injury and death rates for rear-facing children in Sweden are near zero because of this.

Unfortunately, some carseat advocates and even some pediatricians are not fully aware of the important safety benefits that rear-facing carseats provide.   Some still adhere to obsolete recommendations from many years ago.   In fact, the policy statement from the American Academy of Pediatrics says, "Children should face the rear of the vehicle until they are at least 1 year of age and weigh at least 20 lb to decrease the risk of cervical spine injury in the event of a crash.  Infants who weigh 20 lb before 1 year of age should ride rear facing in a convertible seat or infant seat approved for higher weights until at least 1 year of age.  If a car safety seat accommodates children rear facing to higher weights, for optimal protection, the child should remain rear facing until reaching the maximum weight for the car safety seat, as long as the top of the head is below the top of the seat back."  Links on this issue to other websites and organizations can be found below.

Have More Questions?

The links above will answer many questions.  We also have a more complete links page, a Frequently Asked Questions (FAQ) page with references to more sources of information and a Guide to Carseat Selection and Use.  Finally, we would be very happy to try to answer any questions or problems you may have regarding specific seats or vehicles.  Please post them at our FORUMS.

Version 2.0, 2/29/2008. All Website Content Copyright © 2001-2008, Car-Safety.Org™ and/or its Owners, P.O. Box 461, Naperville, IL, 60566. All Rights Reserved.