Car Seat Safety: Rear End Collisions

We know that when used properly, rear-facing car seats will provide significant safety advantages in frontal, frontal offset and side impact crashes. However, a question that is often raised is how a rear-facing car seat would fare in a rear end collision. We brought you Rear Facing: Just the Facts and because we want you to be fully armed with all the facts we have done our research and are going to elaborate a little bit more on rear collisions and rear facing car seats.


Seventy-five percent of all car crashes are frontal and twenty percent are side impact. These types of crashes are not only more frequent but also far more severe than rear-end crashes. This leaves rear end crashes making up only five percent of total car accidents, and usually occur at far lower speeds than frontal accidents. Logically, you are safest when using a seat that will protect your child in the most common types of collisions, which are frontal and side impact. However, some research points to rear facing car seats still being better off in a rear facing collision.

In a rear end collision both vehicles are moving in the same direction, which throws the car that is hit from behind, forward. This means that the forces of the crash are far lower than they are in a frontal impact where the vehicle comes to a sudden halt. In a rear facing seat, the child’s vulnerable head is positioned towards the center of the vehicle, away from the point of impact. So it would stand to reason that rear facing could be considered safer in all types of crashes.

The only time rear facing would have the same effect as forward facing would be if you were to reverse into something at high speed, which is extremely unlikely to occur.


Breaking down the accident: Crash Energy & Ride Down Time

Crash Energy: Vehicle speed is a very important factor to the energy of a crash. Frontal and frontal offset crashes are the most severe and produce the most “crash energy” because they often happen with both vehicles traveling at high speeds in opposite directions.

Ride-Down Time: Child passenger safety advocates stress the importance of “ride-down time.” Ride down time is the amount of time it takes for a vehicle to come to a complete stop during a crash. The total force on the passenger is increased with both the weight of the person and with the speed that they were traveling before the crash.

The total force on the passenger decreases significantly as the time it takes to stop increases. Most of the time we have no control over the speeds involved in a crash, however, there are some things that help increase the time it takes for a passenger to come to a stop. As mentioned earlier, during a frontal crash the vehicles are often traveling in opposite directions and moving at high speeds. When they collide both vehicles stop very suddenly, in only small fractions of a second. Even a slight increase in your stopping time can reduce the risk of injury considerably.

Fortunately, rear-end crashes allow for a lot more ride-down time than frontal crashes. As we previously mentioned, the speeds involved in a rear end collision are usually lower than a frontal crash. This creates far less potential crash energy. The two vehicles are also not usually moving toward each other like they would be in a frontal crash. Therefore in many instances one vehicle is allowed to “give,” and the overall ride-down times for both vehicles are much greater, translating to less force being transferred to the passengers.

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The Importance of a Tight & Proper Installation

In the vehicle, the vehicle frame, advanced seat belts, and airbags are all designed to assist passengers in slowing down more gradually during an accident. The purpose of a car seat is to prevent ejection and allow the child to be coupled tightly to the the vehicle. The reasoning is to allow the vehicles frame to provide the necessary ride down time. If your car seat is not installed properly and the installation is loose the child will get less ride down time. This can cause a more severe crash into the harness. 

When properly and tightly installed the child will slow down more gradually during the crash and reap the benefits of the “ride down time” provided by the vehicle frame.

If you are concerned about the installation of your car seat, it is always better to be safe than sorry. Get your car seat checked by a Child Passenger Safety Technician. They can check for proper installation of your car seat and assist you in a correct install if necessary. Visit their website to find one in your area!

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From A Physics Standpoint:

Delta is the Greek symbol used for change in mathematics, and “V” means velocity. This makes delta-V a change in velocity.

In the case of a rear end collision here’s the physics assuming vehicles of equal weight. If a vehicle traveling at 50 mph is rear ended by a vehicle that is doing 60 mph, we have final closing speeds of 60-50, or a delta v of 10 mph. The delta-v’s may vary slightly. The front vehicle may be pushed ahead about 2 mph by the collision. While the vehicle smashing into the front vehicle may be slowed by a delta-v of about 4 mph.

To sum it up: If you were in a vehicle being rear-ended you would only experience about 10 mph hour change in velocity.

In the case of a head on collision where two vehicles are going 65 mph, that’s a delta-V of 65 mph and a closing speed of 130 mph.

To sum it up: If you were to hit someone head on you would experience a 65 mph change in velocity.

What we can infer: The likelihood of getting injured in front collisions is significantly greater than in rear collisions. It’s very uncommon to see a rear end collision where a vehicle is traveling 130 mph striking a vehicle doing 65 mph. But it is not uncommon to see a vehicle traveling, say, 50 mph accidentally crossing the line and hitting another vehicle traveling 50 mph. 

In conclusion, we all want to do everything we can to protect our little ones in the event of an accident. It is primarily for this reason that you should choose to protect them by rear facing them as long as possible. You should choose to maximize their protection for a frontal or side impact crash which is 95% more likely then a rear collision. Through much research we were not able to find any videos that adequately showed what would happen to a rear facing car seat during a rear end collision. Also, there are not a ton of statistics related to this topic. We have brought you everything we know to be factual so that you have all the proper information when deciding how to keep your children as safe as possible.

Are you in search of the safest and best options for rear facing car seats? Check out 13 Car Seats To Keep Your Kids Safer!

Disclaimer: The information provided in this post is meant for educational purposes only. We have spoken to people specializing in the physics of car collisions including their force and energy to gain a better understanding of what would happen to a rear facing car seat during a rear collision. If you have found any additional information on these type of accidents that you would like to share with us, please feel free to share below in the comments. Also, please be aware that the statistics for types of car accidents varies between 1-3% based which reputable source you are examining.

Photo Credits: The Art Of Making A Baby, JoshSemans

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Jessica

Jessica is a holistic health counselor and work from home mom living in the middle of nowhere USA with her sweet little boy! She suffers from a serious case of compulsive globe-trotting and is always counting the days until her next move or adventure. You can often find her trying to get in her exercise in by lunging through the park while chasing after her very energetic little boy! She is constantly fueled and energized by her love for healthy eating and occasionally copious amounts of caffeine.

Comments (4)

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    AJ

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    Great article but it would be much better if you would cite your sources instead of just saying you talked to people. It would give you a lot more creditability.

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    JS

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    I think you’re comparing apples and oranges. The statement from a “physics” standpoint is comparing being rear-ended at 50mph by someone going 60mph (very small variance)…to head on collisions with each car going 65mph at each other (130mph variance). We’re talking light fender bender compared to both cars being annihilated!

    How about a comparison about being rear ended while you’re at a dead stop and someone hits you going 40mph….or you going 40mph and hitting someone who is at a dead stop. Compare how front vs rear facing carseats affects the kids in those instances…with references.

    I’m more concerned about being rear-end by a drunk or someone texting, while I wait at a light, than a head on collision with someone where I could likely swerve out of the way if I’m paying attention.

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      Kirsten Wender

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      I came to this article looking for answers on exactly that. I was rear ended on Saturday while I was at a dead stop and the car who hit me was going 60mph … My 1 year old was rear facing and she bit her tongue pretty badly and had bruises on her chest from the buckle. I am trying to figure out if she would have been better protected front facing in that situation.

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    Jordan

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    How about citing facts with actual data or some sort of proof instead of just writing non sensical bs with no sources to back up your claims the department of motor vehicles says your 500% more likely to be rear ended than you are to actually hit someone . So let’s see some form of proof …

    Reply

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