Tethering - does that make harnessed seats safer?

Hazelandlucy · Jul 31, 2015

Say you have a 5 or 6 yr old that could be harnessed or boostered. A harnessed seat uses a tether that reduces forward head excursion while a booster does not (or at least it doesn't affect head excursion in booster mode, if I understand correctly). Would that not be a major plus for keeping a child harnessed as long as possible?

rachelandtyke · Jul 31, 2015

One of the differences is that a booster seat is going to move forward with the child more since it is coupled to the child with the seat belt as opposed to the seat being attached to the car and the child being attached to the seat. Someone with more technical prowess can explain it better.

bubbaray · Jul 31, 2015

Google HANS device. The argument is that harnessed seats increase neck loads. Not exactly comparable because kids usually don't wear helmets in cars, but you will get the idea

Hazelandlucy · Jul 31, 2015

rachelandtyke said:
One of the differences is that a booster seat is going to move forward with the child more since it is coupled to the child with the seat belt as opposed to the seat being attached to the car and the child being attached to the seat. Someone with more technical prowess can explain it better.

That makes sense that in terms of crash energy, a booster makes less of a sudden stop on the child. But is the head going to have more of a chance of striking something?

What causes more injuries in real life - neck forces (i.e, broken necks) or head injuries?

SafeDad · Jul 31, 2015

In both cases, upper body restraint is a belt that comes over the shoulder. If used correctly, there probably isn't a huge theoretical difference between a tethered harness seat and a belt-positioning booster in terms of forward head excursion.

A backless booster has a slight theoretical advantage as the occupant is initially positioned farther back into the seat.

A 5-point harness has been conjectured to offer a possible advantage in side impacts.

I haven't seen any recent studies offering any compelling evidence for a real-world advantage of harness vs. booster for kids 5 or older, though.

lourdes · Jul 31, 2015

So when I read things like this I feel I am doing the wrong thing by re harnessing my 7 y/o.....

rachelandtyke · Jul 31, 2015

lourdes said:
So when I read things like this I feel I am doing the wrong thing by re harnessing my 7 y/o.....

If she can't safely sit still in her booster, then it is the right thing to do until she can. She's not safe in the booster if she's not in position.

SafeDad · Jul 31, 2015

lourdes said:
So when I read things like this I feel I am doing the wrong thing by re harnessing my 7 y/o.....

Switching to a booster after 4 years and 40 pounds is mostly a choice based on the child's maturity to be able to properly buckle and remain seated in position.

As for safety, neither is the wrong thing if installed and used correctly. We just don't have any recent studies to say which one might be preferable, based on actual injury or fatality data.

It's definitely not like extended rear-facing vs. forward-facing, where there are some statistics to show a clear advantage for rear-facing to at least 2 years old, and probably longer.

murphydog77 · Aug 1, 2015

Yeah, there isn't any data to show one way or another whether harnessing or boostering is better/safer. Like Darren said, it's based off maturity for the most part. We're lucky now to have much better harnessed seats that have higher weight limits and higher harness slots than even 10 years ago. Ten years ago, if your 3 yr old was over 40 lbs. or very tall, you were stuck buying a Britax seat or a very hard to get Fisher Price seat to harness them, or you stuck them in a booster seat and crossed your fingers.

As long as either a tethered harnessed seat or a booster seat is being used properly during the time of a crash, a child will fare much better than one who is in a misused seat, no matter what type of seat.

zeo2ski · Aug 2, 2015

And what about untethered harness vs. a booster? Assuming the 5-6 to could sit properly to booster and no TA is available.

SafeDad · Aug 2, 2015

zeo2ski said:
And what about untethered harness vs. a booster? Assuming the 5-6 to could sit properly to booster and no TA is available.

For a child over 4 years and 40 pounds and mature enough to use a booster, I would opt for the booster vs. an untethered harness seat for my own children. Still no data to support this, though.

LC2003 · Aug 3, 2015

CPSDarren said:
For a child over 4 years and 40 pounds and mature enough to use a booster, I would opt for the booster vs. an untethered harness seat for my own children. Still no data to support this, though.

But not a lot of kids are that responsible. Of my four kids old enough for boosters, only one could have had a chance of sitting in his booster seat in a responsible way at age 4. So that leaves an ongoing problem for a lot of parents here in the U.S. American cars don't have to have all the tether anchors like Canadian cars, and we have the thing here on this board being to really stress that tether anchor, despite an admitted lack of data... I don't know if this is the clearest message to be putting out there.

LISmama810 · Aug 3, 2015

LC2003 said:
But not a lot of kids are that responsible. Of my four kids old enough for boosters, only one could have had a chance of sitting in his booster seat in a responsible way at age 4. So that leaves an ongoing problem for a lot of parents here in the U.S. American cars don't have to have all the tether anchors like Canadian cars, and we have the thing here on this board being to really stress that tether anchor, despite an admitted lack of data... I don't know if this is the clearest message to be putting out there.

He did say over 4 and 40 pounds AND mature enough. (Plus he's talking about when there's no tether anchor, which does happen but isn't nearly as common as it used to be, and can often be rectified by moving kids around.) I don't at all get the impression that people on this board are quick to take kids out of harnesses, but when no tether anchor is available, decisions need to be made.

SafeDad · Aug 3, 2015

LISmama810 said:
He did say over 4 and 40 pounds AND mature enough.

Right, though I didn't put in in CAPS for emphasis;-) If they're not mature enough to use a booster, the vast majority of vehicles on the road today do have standard or optional tether anchors and one of those positions should be used for any forward facing harness seats if possible.

When that is not possible, there are some harnessed seats that pass the stricter head excursion standard without a top tether. There are also some combination models that offer some upper restraint by clever routing of the shoulder belt, like some Recaro and older Britax models.

bubbaray · Aug 3, 2015

LC2003 said:
American cars don't have to have all the tether anchors like Canadian cars, .

The number of TA in the vehicle isn't usually different between the countries, especially now post-LATCH (which we call UAS).

If my kids had been over 40lbs at 4 I would have moved them to boosters.

SafeDad · Aug 3, 2015

LC2003 said:
American cars don't have to have all the tether anchors like Canadian cars, and we have the thing here on this board being to really stress that tether anchor, despite an admitted lack of data...

There is definitely data to support top tether anchor use for forward facing carseats. Most severe and fatal injuries to children in vehicles are head injuries due to head excursion and use of a top tether on most carseats allows them to meet a stricter head excursion testing standard. With few exceptions, top tethers are always highly recommended for forward-facing harness carseats.

Top tethers have been standard in vehicles for about 15 years now in the USA and optional in many more vehicles for over 25 years, though it is increasingly difficult to find parts to add them now to the oldest vehicles still on the road. Certainly there are some very old vehicles still on the road where a top tether is not possible, but hopefully we can guide a parent to the best option for their situation with some relevant information.

Tethering - does that make harnessed seats safer?

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