Can we talk lap belts & boosters?

selinajean · Jun 12, 2010

This has really been bugging me for a while and I just can't wrap me head around it, so please help!

The law states that if a lap-only belt is the only available option for a child in a booster seat, that the booster may not be used. The child must sit in the belt only, directly on the vehicle seat.
I understand that lap belts are dangerous for everyone and should be avoided. I do not understand however how it is safer for a child to sit on the vehicle seat instead of using the booster with the belt? Is it not slightly less dangerous to have the lap belt at least positioned correctly so that it is not riding up on the tummy? (I know that all booster manufacturers say not to use with a lap belt, but I am guessing this is just b/c lap belts are not safe in general????)

I don't have lap belts anymore in our vehicle but I have been asked about this scenario quite a few times lately. I want to know why the law is that way.

Thanks!

QuassEE · Jun 12, 2010

Although we used to say definitively that the lapbelt only was "safer" than a booster with a lapbelt because of the fact that the booster contributes to allowing a greater range of motion in crash test dummies, I'm not 100% on this anymore. You bring up a good point--the booster at least allows that lap-only belt to be properly positioned, which may not be the case without.

There's a really good video of booster w/ lapbelt and lapbelt only out there somewhere--I believe it's in the US curriculum. It shows that, in crash testing, the lap/booster dummy actually folds in two quite a bit more than the lap-only dummy. So basically, you could look at this like an increased head excursion situation with harnessed seats, only on the extreme.

But, as far as I've heard more recently..there's some newer debate on which may be safer with real children. Until we have more information, however, unless the booster seat specifically allows for use with lap-only (eg. Britax Laptop/Romer Vario, expired (Grand) Explorers) then it's a no go. Thankfully we have higher weight harnessed seats--and thankfully older vehicles with lapbelts in the rear don't have front passenger airbags.

-Nicole.

safeinthecar · Jun 12, 2010

There is actually quite a bit of controversy on this issue do to an article that came out awhile back suggesting that boosters with lap-only belts may be beneficial.

Official recommendation by car seat experts, and one I agree with BTW, is to NEVER use a booster with a lap-only belt. The logic behind it is this:

While using a booster may help prevent abdominal injuries by improving belt fit, raising the child's center of gravity by putting them on a booster will also increase the likelihood of the child's head contacting forward structures in the vehicle. Head protection trumps abdominal protection, so you are trading off injury potentials. In addition to this, many vehicles with lap-only belts will also not have tall enough seat backs to provide adequate head support for a child in a low back booster (which we all know the majority of parents use).

mommycat · Jun 13, 2010

:yeahthat: That's how I understood it as well.

Adventuredad · Jun 13, 2010

Good question and answers. Another possible problem with using lap belt and a high back booster is the added weight which will be pushing a child in the back during a frontal collision.

This is an important factor when choosing a high back booster installed only with seat belt. At 50 km/h )31 mph) a hbb weighing 4 kg (9 lbs) is pushing with an extra 160 kg (352 lbs). This is absorbed by seat belt and chest of child but lower forces are of course always desirable. Most booster seats are far heavier than 4 kg so forces would be much higher.

It's difficult to say how much extra weight would be added with a lap belt but it would not be insignificant.

Another point with no lap belt together with hbb is likely also to avoid confusing parents.

selinajean · Jun 13, 2010

Thanks for the answers everyone! :thumbsup:

Beckers · Jun 13, 2010

Also, one of the dangers of lapbelt is the pressure put on the spine when the top half of the body is thrown forward while the hips are held down. If the crash tests show that the booster causes the body to fold more, then I would think that means more pressure on the spine.

selinajean · Jun 13, 2010

Okay, new question....same sort of train of thought.

What about l/s belts without any sort of locking mechanism? (Sliding latchplate, no locking mechanism at retractor.) How exactly does this work as a belt? (Sorry, this is not covered in the BCAA course) How does it stop the occupant from moving forward if there is nothing to stop the belt from extending? Is there any rule against using a booster seat with that type of belt? It doesn't seem safe.

tiggercat · Jun 13, 2010

selinajean said:
Okay, new question....same sort of train of thought.

What about l/s belts without any sort of locking mechanism? (Sliding latchplate, no locking mechanism at retractor.) How exactly does this work as a belt? (Sorry, this is not covered in the BCAA course) How does it stop the occupant from moving forward if there is nothing to stop the belt from extending? Is there any rule against using a booster seat with that type of belt? It doesn't seem safe.

In the event of a collision or sudden stop, the emergency locking retractor engages. This holds the occupant in place.

selinajean · Jun 13, 2010

tiggercat said:
In the event of a collision or sudden stop, the emergency locking retractor engages. This holds the occupant in place.

Thanks!

InternationalMama · Jun 13, 2010

QuassEE said:
however, unless the booster seat specifically allows for use with lap-only (eg. Britax Laptop/Romer Vario

I just wanted to clarify that the Laptop/Vario is not a booster. It does not in any way *boost* the child up to a different position and from a crash test perspective it acts more like a harness than a booster, the difference being that in the event of a crash it allows the neck to move with the forward motion of the head more than a harness does.

This thread was really interesting to read. Thanks for asking, OP.

selinajean · Jun 13, 2010

InternationalMama said:
I just wanted to clarify that the Laptop/Vario is not a booster. It does not in any way *boost* the child up to a different position and from a crash test perspective it acts more like a harness than a booster, the difference being that in the event of a crash it allows the neck to move with the forward motion of the head more than a harness does.

This thread was really interesting to read. Thanks for asking, OP.

I had to look up those restraints to see what they were. How neat! They look like a little table top. My son would love that....he is always drawing in the car. LOL

I'm really enjoying this thread too. So glad that I finally asked. Thanks for all of the input!

QuassEE · Jun 14, 2010

InternationalMama said:
I just wanted to clarify that the Laptop/Vario is not a booster.

No, they're not. I just lumped them in without separating the two.

-Nicole.

Can we talk lap belts & boosters?

selinajean

New member

QuassEE

Moderator - CPST Instructor

safeinthecar

Moderator - CPS Technician

mommycat

Well-known member

Adventuredad

New member

selinajean

New member

Beckers

Active member

selinajean

New member

tiggercat

New member

selinajean

New member

InternationalMama

New member

selinajean

New member

QuassEE

Moderator - CPST Instructor

Car-Seat.Org Facebook Group

Sponsors

Forum statistics