Can you use LATCH and seat belt?

[My3Sons]

Both my husband and I were thinking it seems safer to use both in case one fails. Though we haven't tried it because we get a tight fit with LATCH. (07 T&C)

The manuals don't say anything about it. I thought I read somewhere on here that it's a no-no but I can't find the thread.

Is it incorrect to use both LATCH and the seat belt? If so, what is the reasoning? Thanks.

[southpawboston]

you can not use both. you can only use one OR the other. the reasoning is that it has not been crash tested that way... the crash tests are done with only one or the other method, and the two together may interfere with one another.

[crunchierthanthou]

No, you only use the seatbelt or the lower anchors. The ff top tether is always used when available.

[skaterbabscpst]

As SPB said, no you can not use them together. It's strictly either/or, never both.

[mcomommy]

Good question I was just about to ask it myself

[safeinthecar]

I've posted this explanation in other threads, so I'll just cut and paste it here.

I have had seats come in that seemed to be tightly installed because latch and the seatbelt were both used, but in reality, neither system was restraining the seat at all. An example, (contains reason why most cars do not allow you to borrow latch anchors from outboard to use in center.)

A father came in with a Century Smart V infant seat in a Ford Explorer. It was installed with latch (add on kit) in the center using outboard anchors. The seat belt was also routed through the seat also, however, the way the belt sat on the edge of the shell, it was in non-locking mode.

Issue with latch: There are three basic ways that latch anchors are installed in cars.

The most common way is that two bars, each containing 2 latch anchors are bolted to the vehicle or seat frame on each of the outboard positions. The bar that the latch anchors are attached to is actually about 10 inches longer than the spacing of the latch anchors. Most cars do not have the spacing to install 3 of these side by side. If you were to use the inboard anchors for each bar to install a seat in the center, the direction the car seat would be pulling on the anchor during a crash would be counter to the direction that the bolt is intended for and would strip the threads leaving the car seat unrestrained.

The second most common way, and the way that is found in most cars that do allow latch use in the center, is that a long bar containing 4-6 latch anchors is welded to the vehicle or seat frame. Since the system is welded rather than bolted, the direction of the pull on the anchor is no longer an issue. Note, if you can flip one section of the seat forward you do not have this system.

Third way latch is installed, but by far the least common, is that latch anchors are built into the seat of the vehicle. As in each anchor individually welded or bolted on.

Note: you have no way of knowing FOR SURE what type of system you have unless the manufacturer tells you. FOLLOW DIRECTIONS AT ALL TIMES.

In the case of the Explorer I am talking about, we called the manufacturer and found out that they use the same latch equipiment as Saab, which I know is the first kind, because that is who I got the latch anchors for my demo bench from.

Therefore his car seat was not really installed with lath at all.

Problem with the seat belt:

The seatbelt sat at an unlocked angle against the car seat base. The female end seatbelt could not be twisted or shortened with a belt shortening clip as it was encased with a plastic sleeve.

Therefore this rock solid car seat was not actually installed in this car at all.

This particular example is not the only time I have seen this kind of thing happen, it just sticks in my mind because it was the first time I saw it.

HTH,

Kimberly

[Elizasmom]

Although I understand the issues explained above, I am guilty of using LATCH and the seatbelt. I have a fear of one failing. I asked Britax about it, and they said that it was okay as long as I install either the belt or the LATCH straps loosely so they don't interfere with the "ride down" that each is designed to allow for in a crash. Since my daughter is under 48 pounds, I first install it using LATCH and the tether to get a super-tight install. Then I route the belt extremely loosely. There's a ton of slack in it.

My older daughter was in a severe accident, and the LATCH straps stretched to double their normal length. I know this is normal, but it really brings home the forces involved in a crash, and it scares me that someting could fail. What if the guy in the factory forgot to tighten a bolt on the LATCH bars? Incidently, I also had the belt installed loosely in the seat that was crashed.

Does anyone see any issue with what I'm doing given that Britax said it was okay? I have a Britax seat in a Sienna captain's chair.

[Connor's Mom]

Originally Posted by Elizasmom

Although I understand the issues explained above, I am guilty of using LATCH and the seatbelt. I have a fear of one failing. I asked Britax about it, and they said that it was okay as long as I install either the belt or the LATCH straps loosely so they don't interfere with the "ride down" that each is designed to allow for in a crash. Since my daughter is under 48 pounds, I first install it using LATCH and the tether to get a super-tight install. Then I route the belt extremely loosely. There's a ton of slack in it.

My older daughter was in a severe accident, and the LATCH straps stretched to double their normal length. I know this is normal, but it really brings home the forces involved in a crash, and it scares me that someting could fail. What if the guy in the factory forgot to tighten a bolt on the LATCH bars? Incidently, I also had the belt installed loosely in the seat that was crashed.

Does anyone see any issue with what I'm doing given that Britax said it was okay? I have a Britax seat in a Sienna captain's chair.

I personally would not take the advice of a random phone tech on doing something that is specifically against manufactures instructions/guidelines.

[skaterbabscpst]

Unless they gave that to you in writing, I would not do it. Britax has repeatedly said they they do not allow both to be used together.

[Elizasmom]

It doesn't seem to be "specifically against manufacturer's instructions/guidelines" in the sense that the manual is silent on the issue. I believe two different people at Britax gave me the same answer, and they didn't seem like they were just winging it. I usually call back to make sure I get the same answer rather than trusting random people. I agree that one shouldn't jerry-rig a car seat install, but it just seems logical to me that this would be okay.

[Elizasmom]

I just read the last comment. They told me this a year or more ago. I wonder why they've changed their tune. Is that in writing somewhere? They were very specific that I could only do it if I left one very loose. I'll be calling them and reconsidering my install. Thanks.

[skaterbabscpst]

They've always said no, but Britax CS reps have been known to say off the wall things that bear no resemblance to reality before.

Don't do it.

[snowbird25ca]

Originally Posted by Elizasmom

Although I understand the issues explained above, I am guilty of using LATCH and the seatbelt. I have a fear of one failing. I asked Britax about it, and they said that it was okay as long as I install either the belt or the LATCH straps loosely so they don't interfere with the "ride down" that each is designed to allow for in a crash. Since my daughter is under 48 pounds, I first install it using LATCH and the tether to get a super-tight install. Then I route the belt extremely loosely. There's a ton of slack in it.

My older daughter was in a severe accident, and the LATCH straps stretched to double their normal length. I know this is normal, but it really brings home the forces involved in a crash, and it scares me that someting could fail. What if the guy in the factory forgot to tighten a bolt on the LATCH bars? Incidently, I also had the belt installed loosely in the seat that was crashed.

Does anyone see any issue with what I'm doing given that Britax said it was okay? I have a Britax seat in a Sienna captain's chair.

Short answer is that no, it is not ok to install a seat with both LATCH and seatbelt.

I think what Britax was addressing when you asked the question, is an issue that has arisen as some vehicle manufacturers are now instructing parents to loosely thread the vehicle seatbelt and buckle it to prevent strangulation hazards. So maybe they're saying if it's there but not tightened, it's ok? Still doesn't sound right to me, but maybe that's what they were commenting on...

In the situation as you're describing, a loose seatbelt isn't going to do diddly squat anyways. The seat is installed with the LATCH belt, and if the LATCH belt were to fail, the seat would've already moved far enough due to slack in the seat belt it wouldn't really serve any purpose anyways.

I will say, that in the case of a MA and BLVD who don't route the LATCH belt through a belt path, I can see how loosely threading and buckling and not tightening a seatbelt at all when a vehicle manual recommends it could be ok. If the LATCH belt and the vehicle seat belt are sharing the same space though, it's a recipe for disaster.

My experience with seats installed with both has also included that the extra bulk added into the belt path interferes with adjustment of the harness - in the case I'm thinking of, the harness couldn't be tightened enough, and it was very hard to tighten at all.

Additionally, seatbelts are designed to have a bit of give and maintain strength, putting both belts against each other is going to affect how much the seatbelts give in a crash. Even if they didn't physically interfere with each other during the installation of the seat, they could still affect crash performance of the restraint.

In the end, it comes down to that no car seat manufacturer is sending out manuals telling parents to use both. And if a manual doesn't explicitly tell you to do it, then it's not authorized. It's impossible for them to cover every single "DO NOT" in a manual, although I think that DO NOT use lower anchors and vehicle seatbelt at the same time should become one of the standards warnings...

[Connor's Mom]

Originally Posted by Elizasmom

Is that in writing somewhere?

Taken directly from page 2 of the Marathon manual......
"Secure this child restraint with the vehicle’s child restraint anchorage system if available or with a vehicle belt."

And like skaterbabscpst said, this has always been part of Britax's instructions since LATCH was incorporated into their seats.

[Elizasmom]

"In the situation as you're describing, a loose seatbelt isn't going to do diddly squat anyways. The seat is installed with the LATCH belt, and if the LATCH belt were to fail, the seat would've already moved far enough due to slack in the seat belt it wouldn't really serve any purpose anyways. "

It would serve the purpose of not letting my child fly through the windshield in a crash, which is my whole reason for doing it. My fear is really my child coming completly free to fly through or out of the van

As someone else said, with the Marathon the belt path and the LATCH bars are not one and the same. I wouldn't think of doing it otherwise, but I will reconsider what I'm doing based on your comments.

[skaterbabscpst]

Originally Posted by Elizasmom

It would serve the purpose of not letting my child fly through the windshield in a crash.

No, it wouldn't. LATCH is not a backup for the seatbelt, nor is the seatbelt a backup for latch. In the situation you describe, not only would the redundancy not work the way you think it will, it could and probably would cause MORE injury to your child.

[Elizasmom]

If the LATCH anchors failed, the seatbelt should still hold. I'm not disputing that there may be issues with what I'm doing and that I should probably stop, but I don't see how you can say that the belt would also unbuckle itself just because the LATCH anchors did.

If the LATCH anchors were defective and broke away, I'd be very glad to have belted it too. I don't see how there could be any worse situation than nothing at all holding the car seat in. However, if there are risks associated with doing this, I have to weigh that against the unlikely event that it would be a benefit.

[snowbird25ca]

Originally Posted by Elizasmom

If the LATCH anchors failed, the seatbelt should still hold. I'm not disputing that there may be issues with what I'm doing and that I should probably stop, but I don't see how you can say that the belt would also unbuckle itself just because the LATCH anchors did.

If the LATCH anchors were defective and broke away, I'd be very glad to have belted it too. I don't see how there could be any worse situation than nothing at all holding the car seat in. However, if there are risks associated with doing this, I have to weigh that against the unlikely event that it would be a benefit.

Well, if I was going to worry about LATCH anchors failing, I would install the seat with the seat belt instead.

I could see that the force the car seat would already have by the time it actually impacted the seatbelt could cause a double impact IF the car seat stayed in the vehicle. And that force could potentially cause the seatbelt to fail too - difference between holding weight back, and being impacted with forceful weight in a crash considering that if the lower anchors had failed, the seat would travel a ways before meeting the vehicle seatbelt. We don't KNOW that the seat belt would hold. We also don't KNOW that it would definitely fail. But there is absolutely a higher risk of the seatbelt complicating matters in the event the lower anchors failed, than there is of the lower anchors failing in the first place.

Both the lower anchorage system and the seatbelt anchors/webbing must meet strict standards and quality control tests. I would spend more time worrying about brakes failing, an airbag deploying for no apparent reason or a tire blowing out than I would on lower anchors failing or a seat belt failing.

For me, adding a definitive risk in order to minimize an extremely improbable risk, just doesn't add up. The fact remains that no car seat is tested and approved for use with both seat belt and LATCH installation. And personally, I'm not willing to turn my child into a crash test dummy.

[skaterbabscpst]

I didn't say the seatbelt would release. I said that it would cause more injury than it prevent by having it attached.

[southpawboston]

Originally Posted by skaterbabscpst

I didn't say the seatbelt would release. I said that it would cause more injury than it prevent by having it attached.

that's not a known fact... that's speculation. i'm not supporting either side here, just sayin'

[joolsplus3]

If the LATCH fails, then it will have at least done the job of precrash positioning so yes, the seatbelt WOULD be a good backup system. There's no real world data yet showing that using both systems is harmful (as much as I've tapdanced around saying it in the past, making up reasons to fill in the blanks of 'why not?' left in the manuals...).

Originally Posted by Elizasmom

If the LATCH anchors failed, the seatbelt should still hold. I'm not disputing that there may be issues with what I'm doing and that I should probably stop, but I don't see how you can say that the belt would also unbuckle itself just because the LATCH anchors did.

If the LATCH anchors were defective and broke away, I'd be very glad to have belted it too. I don't see how there could be any worse situation than nothing at all holding the car seat in. However, if there are risks associated with doing this, I have to weigh that against the unlikely event that it would be a benefit.

[Elee]

Consumer Reports explained it this way:

• Never install a car seat using both the LATCH strap and the vehicle safety belt. This restricts the belts from absorbing crash energy.

[onlydarksets]

Originally Posted by safeinthecar

I've posted this explanation in other threads, so I'll just cut and paste it here.

...

Problem with the seat belt:

The seatbelt sat at an unlocked angle against the car seat base. The female end seatbelt could not be twisted or shortened with a belt shortening clip as it was encased with a plastic sleeve.

Therefore this rock solid car seat was not actually installed in this car at all.

This particular example is not the only time I have seen this kind of thing happen, it just sticks in my mind because it was the first time I saw it.

HTH,

Kimberly

I'm trying to follow this, as I need to upgrade our car seats, but I do not understand how the seatbelt not being secured (by twisting or using a clip) means that the car seat is "not actually installed in this car at all". Could you help me understand this?

Thanks!

[ThreeBeans]

Originally Posted by onlydarksets

I'm trying to follow this, as I need to upgrade our car seats, but I do not understand how the seatbelt not being secured (by twisting or using a clip) means that the car seat is "not actually installed in this car at all". Could you help me understand this?

Thanks!

She's referring to a specific type of seatbelt. Some seatbelts lock at the buckle with a locking latchplate. The belts need to be perfectly parallel for the seat belt to lock, otherwise they can slide loose. If the belt path of the carseat forces the buckle to lie in an unnatural position, then the locking latchplate is NOT locked.

A good cure for that in some seats is to twist the female buckle so that it lies in a lockable position, but since this car's buckle stalks had plastic trim around them, that couldn't be done.

[onlydarksets]

OK, I see. I interpreted the post I quoted as being a global explanation for why LATCH + seatbelt will not work. In fact, it was a description of why a particular LATCH + seatbelt installation was, in fact, not secured at all. Thanks for the clarification!

That being the case, it sounds like the only explanation is that the two systems used together may impact the ability of either one to adequately absorb the force of impact, and, because manufacturers don't perform tests with both systems use simultaneously, it's impossible to say that it's safer, and, in fact, it may be less safe. Hence the "do you want to make your child a crash test dummy" comments.

Is that about right?

Thanks!