Question Which CR and vehicle manufacturers/models prohibit locking the seat belt with boosters?

jjordan said:

I *think* our 2008 Kia Sedona said not to lock the seatbelt for booster riders. I will double-check tonight if I remember.

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LISmama810 said:

I think Recaro prohibits it.

And the Prius prohibits it.

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mamakc said:

Why is it not recommended? The harmony dream time manual advises TO lock the belt if the vehicle allows it.

-Krista
DD~5~Monterey & Dreamtime
DS~3~Complete Air 65 LX & Maestro
DN~1~Complete Air LX

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> At University of Michigan Transportation Research Institute, we
> researched the practice of switching seat belts to the locking mode when
> used with boosters as part of the development of an updated version of
> the UMTRI document on best practices in child passenger safety (coming
> soon.) When speaking with several vehicle manufacturers, most were
> against the practice of locking seatbelt with boosters because seatbelts
> are designed to allow the torso to rotate past vertical in a frontal
> crash, which acts to prevent submarining below the lap part of the belt
> when there's no crotch strap. When we have tested boosters with the 6YO
> and 10YO dummies, they definitely generate sufficient belt loads to
> activate the locking mechanism in a severe crash. I suspect that some
> of the reports of nonlocking belts may be from a combination of low
> occupant mass and low crash severity.
> The suggestion to lock the seatbelt with boosters to deal with wiggly
> out-of-position kids arose years ago when there weren't higher weight
> harness products available. These would be the best choice if a child
> can't sit properly in a booster seat. Since one of the key curriculum
> directives is to follow the manufacturers' directions, if the
> manufacturers don't tell you to lock the seatbelt with a booster, CPST's
> shouldn't be suggesting it as an option for parents.
>
> Kathy Klinich
> University of Michigan Transportation Research Institute

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Kecia said:

Pre-tensioners are rarely a feature found in rear seating positions. The current curriculum does not address this particular issue at all. And I am not personally aware of any documented downside to locking a switchable retractor on a child in a BPB (other than a few CR or vehicle manuals which simply state not to do this).

In fact, the only real technical info I have on the subject is from the instructor manual of the previous CPS Tech curriculum which states that this is (was) an acceptable practice at the time. Switching the retractor to ALR was listed as a "fix" for BPBs with shoulder belt slack issues (when the belt couldn't retract properly because it was caught in the guide) and also recommended to help "wiggly" children stay in place.

According to the instructor notes in the 2004 curriculum manual:

The issue was addressed by the SAE (Society of Automotive Engineers) Children's Restraint Task Force and it was "generally agreed that... the use of an ALR/ELR in the ALR mode was favored by installation experts (and many parents) because it kept the child in position against the seat back. That practice did not draw any objections from the others."

"The theory is that the latch plate still allows the belt to slip from the lap to the shoulder belt as the upper torso loads the latter. Locking the retractor (at the top) merely acts like the ELR kicking in early - which is fine."

Keep in mind that this is old info and perhaps there is some new info on the subject that I am not aware of. But as far as I know, there is no general recommendation that says to not lock the seatbelt in ALR mode.

ETA: Cross-posted so I didn't see the previous reply from creideamh. Nice to see that there is some updated info on this subject.

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The rear (or front passenger) safety belts use a special auto-lock feature designed to allow a child restraint to be used in these positions without an added locking clip. They normally lock only under extreme or emergency conditions (emergency lock mode). However they can be adjusted so that they remain fixed and locked when a child restraint system is placed in these positions. (Use this auto-lock mode only to secure a child restraint, never for passengers restrained by the safety belts.)

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