Harnesses NOT safer than HB boosters for older children?

Hazelnut

New member
I read this periodically on other boards' safety forums. I was under the impression that any booster is always a step down in safety. Yet a few people say that that is misinformation, or it's not actually tested and proven that 5pt harnesses are safer on kids who are older than 4. Do those assertions have any merit?
 
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Genevieve

CPST Instructor
I don't think there is any hard data comparing a harness and booster for bigger, older children. From my understanding, they are both very safe (again, talking bigger/older kids here) and either one would be a fine choice.
 

Maedze

New member
That's correct. If a child is at LEAST four years old and at LEAST 40 pounds AND (and this part is crucial) can sit upright without slouching, wiggling, leaning, slumping or squirming out of position, 100% of the time for 100% of every ride, there is no evidence that a harness is safer than a booster.


Only a tiny percentage of four year olds are able to behave that maturely in a booster. I'd say MOST kids could sit safely in a booster by six, however.
 

emandbri

Well-known member
Like others said we just really don't know. I personally believe that a 5-point is safer since it distributes crash forces better, protects better in a side impact crash, and better in a rollover.

I haven't posted this yet but my MIL was in a car accident this morning, I will post pictures of the car after I get them off my phone. Her friend was riding in the back seat and she has a BIG RED WELT on her neck and upper chest where the seat belt was and I couldn't help but think that in a 5-point harness the crash forces would have been distributed on both sides instead of one which might have helped.
 

mommy-medic

New member
Personally I disagree. A 5 pt harness spreads out the crash forces over a greater percentage of the child's body surface area, and provides more anchor points in the event of a rollover collision. Heck that's what race car driver's use.
 

Maedze

New member
The 'race-car driver' is a strawman argument, though. We're talking about crash forces that would tear the average minivan into confetti.


Of course, dividing the forces over five points rather than three is certainly better, we just have no evidence that shows it's STATISTICALLY significant.

For example, there's evidence that shows an 18 month old is 500% safer rearfacing rather than forward facing.

Now if you compare that with say a 7 year old in a booster versus a five point harness....well...my guess is the numbers would be closer to less than 1% difference, which is not statistically significant.
 

bobandjess99

Senior Community Member
In addition to what Maedze said, another caveat to the whole "race car driver" argument is that they ALSO have a helmet on which is restrained/attached, such that their HEAD can not fly forward and place too much strain on their neck...kids in 5 pt harnesses do not have that. My understanding is that in a frontal crash in a 5 pt harness, there is extreme stress placed on the neck, because the torso is completely restrained by the harness, such that the head flies forward, putting all of the force of the crash on the neck we are trying so hard to protect. In a booster, the side of the body opposite where the shoulder belt is, also rides forward a bit, as does the entire upper spine, etc, and thus, the forces placed upon the neck are actually LESS than in a 5 pt harness. That is why some countries, like Sweden, do not FF harness, but use a booster right after rearfacing, at about age 5. And to me, it makes PERFECT sense that this would be true, given my admittedly basic understanding of physics and crash dynamics.

I personally do state that there is no EVIDENCE that a harness is safer for a child over 40 lbs and over 4-5 years old, IF they can sit maturly. it *MIGHT* be. It might be equal..it might actually be less safe....we don'tknow,we do NOT have evidence either way.
Again,my understanding, and perhaps someone can chime in here, is that in Sweden, they actually have EVIDENCE (as the result of crash testing) that boostering is safer, which is why they choose it....but again, any testing done would have the dummy in correct position...so I think that even IF boostering is safer technically, you still have to factor the maturity criteria in, and therefore, I hesitate to recommend boosters for kids under 5-6 years old.
I also believe that even IF 5 pt harnesses are safer, it is probably by a smaller margiun, as Maedze stated..I have no evidence for this, of course, but I think it probably would be "statistically insignificant" or else pretty small..
And all of this is why I don't necesarily try to browbeat parents into EH, but I do into ERF..because we know, we have PROOF, that ERF is ridiculously safer....and in the grand scheme of things, I would much rather convince a parent to erf to 18-24 months than eh a 4 year old.
 

Hazelnut

New member
Thanks for the input. The diminishing safety difference certainly makes sense. So, the evidence used in Sweden is not relevant to our HBBs?

My son is 6 and still in his Radian, albeit getting a bit tall. I was beginning to wonder if we should just move on to the HBB, esp. if we need to mess with his little brother's seat to rf past 33 lbs and the seats don't all fit.
 

emandbri

Well-known member
Thanks for the input. The diminishing safety difference certainly makes sense. So, the evidence used in Sweden is not relevant to our HBBs?

Honestly might not. Sweden has GOOD high back boosters with nice side impact protection and if I had to guess I would say over half the kids in the US are in cosco high backs. :whistle:
 

An Aurora

Senior Community Member
So are the more recommended boosters not as good as the Swedish ones either?

I wouldn't say that. Sweden has the Britax Monarch, as did we until a couple of years ago. The Monterrey is pretty comparable to the Swedish boosters too. The OP was saying that the boosters that most kids are in (the cheapy Cosco ones, or the Evenflo, or even the Turbo) are not the same quality as Swedish ones.

ETA: Emily, we cross posted ;)
 

Victorious4

Senior Community Member
Right, there is no comprehensive comparative data. What we do know, however, is that harnesses reduce head excursion.

We also know that the violent movement or ending of movement during a crash is hardly ever the cause of injury. Infants/toddlers/preschoolers are more at risk of internal decapitation from movement because their underdeveloped skeletal structure is combined with a large head:body size ratio. Bigger kids have the benefit of stronger bones & less drastic head:body size ratio, so they're less likely to suffer severe injury when merely impacting the harness (which spreads the crash forces out more on the strongest parts of the body than does a 3 pt. seatbelt with booster).

Those factors considered, it's still worth noting that a boostered child is more likely to impact the vehicle interior (front seatback, window, another passenger, etc.) because boosters inherently result in greater head excursion (forward movement -- the shoulder that isn't under the shoulder belt twists out & around). The crash phase in which the occupants impact the vehicle interior is what most often causes injury.

Using a booster for a child who barely fits the size requirements and/or who might not be mature enough to remain in the crash test dummy pose for the entire length of every trip, even while sleeping, increases the risk of injuries that can be easily enough prevented with a HWH.

Injuries that might happen in a HWH are at least as likely to happen in a booster :twocents:
 

tarynsmum

Senior Community Member
if I had to guess I would say over half the kids in the US are in cosco high backs. :whistle:

If I had to guess I would say most were in inappropriate backless boosters or nothing at all, especially in the age-range we're referring to.

I tend to agree with 3B (Maedze - did I spell that right?). Once a child's mature enough to sit correctly every time, and the booster fits properly, then I feel that a booster is appropriate and would protect a child statistically similarly. The fact that we in the US don't have many GOOD hbbs to choose from makes me feel like I can't really compare with Sweden.
 

heyruthie

New member
I would also like to make a point that is rarely discussed here. When I used to work at the NHTSA, we discussed regularly the engineering fact that EACH STEP AWAY FROM THE ACTUAL PRIMARY CAR RESTRAINT SYSTEM ADDS MORE PROBABILITY OF "LOSS" (otherwise known as failure, misuse, malfunction, etc.) From an "everyday" persepctive, it's like the game of telephone: with each new element introduced, you get farther from the original message.

The same is true with CRs. Adult seatbelts go through RIGOROUS testing to ensure that they do their job (keep the occupant restrained and attached to the vehicle body.) With each new piece of equipment that you add (like a CR) you introduce a new component that can (at some point) fail & also adds movement in a crash. In other words, the car's PRIMARY restraint system (the one actually crash-tested while permanently connected to the vehicle frame) is the adult seatbelt. Anything else is going to be a secondary restraint--usually relying on the adult seatbelt and then introducing a second retraint on top of that (esp. with bigger kids, who HAVE to have a seatbelt install.) When a child is in a booster, they are essentially being restrained by the PRIMARY restraint--the seat belt. When a child is in a harness, they are being restrained by SECONDARY restraints (harness, CR, tethers, etc.) which are all then relying on the PRIMARY restraint (adult seatbelt, anchors, etc.) This whole "adding a step" increases movement in a crash (even a rock-solid install WILL move in a crash) and more importantly, increases risk probability.

So, the whole "racecar driver" scenario is a strawman for another reason: that driver is restrained in a PRIMARY restraint system that has been connected to the vehicle frame. He doesn't hop in there and strap a 5-pt. harness device on that is attached to a REGULAR adult seatbelt! His 5-pt. harness IS the seatbetlt!

It is also my (personal) opinion that the larger the object in question (child!) is, the greater the probability will tend to be of "loss" (which is why we are always trying to top-tether and rear-tether the bigger kids!) This makes sense from a physics point of view.

All that said, I'm CERTAIN, IMHO, that there is a law of diminishing returns with keeping kids harnessed for "as long as possible." At some point, it becomes wise to connect them to the car's primary restraint mechanism, instead of relying on secondary restraints as the child gets larger and larger.

In the end, we would probably all be safer if the adult seatbelt was more like a 5-pt. harness. However, it would be very impractical (think of wearing a dress to work!) and it would also probably suffer from the law of diminishing returns because 3-pt. harnesses have been shown to be VERY effective in keeping passengers safe :)
 

mom1mg

New member
Soooo- I am shocked to see so many people who have the opinion that a booster is as safe if not safer then a harnessed seat for an older child. I have heard the race car driver argument. (Although it makes total sense now that a race car driver is not in a carseat but the harness is part of the car.) But the main reason we re-harnessed our 6.5 year old was because of the fact that a carseat is held in at more then one point (ie seatbelt or latch and tether). I know that there have been some instances where a child in a booster has been ejected because the seatbelt failed and if they had been tethered the carseat may have broken free at one point of contact but at least would not have ejected from the car.

So for some of you who believe a booster is safer - At what age and weight would you think (in general) that a harness becomes less safe? I know that there isn't data to support any of this but I was just wondering how big this mythical "older child" that this thread is talking about is?

Thanks
 

christineka

New member
I'm no expert, but I'm going with 40 pounds and mature enough to sit in a high back booster with good sip. For my ds that's a little over age 6. My seatbelts are not the type known for failure, so I'm not concerned about that.
 

Maedze

New member
Soooo- I am shocked to see so many people who have the opinion that a booster is as safe if not safer then a harnessed seat for an older child. I have heard the race car driver argument. (Although it makes total sense now that a race car driver is not in a carseat but the harness is part of the car.) But the main reason we re-harnessed our 6.5 year old was because of the fact that a carseat is held in at more then one point (ie seatbelt or latch and tether). I know that there have been some instances where a child in a booster has been ejected because the seatbelt failed and if they had been tethered the carseat may have broken free at one point of contact but at least would not have ejected from the car.

So for some of you who believe a booster is safer - At what age and weight would you think (in general) that a harness becomes less safe? I know that there isn't data to support any of this but I was just wondering how big this mythical "older child" that this thread is talking about is?


Thanks

It's not a question of whether a booster is 'less safe' as much as, 'is a harnessed seat SAFER' and I think for older children the answer is either 'no' or 'not statistically significantly safer'.

The instances of seatbelt failure are very, very, VERY rare and seem to be limited to Gen 3 seatbelts.

I think my feeling is (and this is NOT based on any information provided by the tech course or NHTSA, merely personal feeling) is that by 6 years and 40 pounds, a booster or a HWH in a seat otherwise occupied by a head rest and lap shoulder belt are equally safe.

At that point you as a parent need to make a decision based on your particular circumstances. Is your child very wiggly? Does you child have physical deficits that make extended harnessing important? Is your child prone to behavioral or emotional immaturity that make harnessing a safer option? Maybe you drive an older car with very poor IIHS crash ratings and you'd prefer the added side impact protection a harness provides. Maybe your car has a tiny back seat and you're worried about head excursion.

For an older child it is not WRONG to harness, so if you're comfortable with your 6 year old in a Regent there is no reason to run out and buy a booster :)
 

joolsplus3

Admin - CPS Technician
The instances of seatbelt failure are very, very, VERY rare and seem to be limited to Gen 3 seatbelts.

Except for Kyle Miller, who was in a Toyota Sienna :(

Still, seatbelt failure is still such a rare occurrence that it's true, we do not need to even consider it when deciding on booster or harness.:thumbsup:
 

Jeanum

Admin - CPS Technician Emeritus
Staff member
When the seatbelt failure issue and/or KDM video comes up, I like to link to this article by Safety Belt Safe USA that has some reassuring stats about the relative rarity of seatbelt failure, as well as important information on best practices in child passenger and vehicle safety in general:

http://www.carseat.org/Resources/650_YouTube.pdf
 

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