Why don't adults need boosters?

So I was talking to my in-laws and trying to remember the law in our state for sitting in a seatbelt. I couldn't remember the height rule, so I estimated 53" (it's 57") and went in to say that some kids aren't safe in a booster until past that. My MIL was crazy-shocked and said, "I'M only 60 inches, do I need a booster?" As I started to explain the 5-step test and how some kids wouldn't pass it until high school, she said, "But would they HAVE to?" At that point, a small injury occurred with another family member and we didn't finish the conversation. My kid is not even 1 year old yet, so I have some time to figure this out.

So here's my understanding of the 5-step test. Please help me understand:

1. Does the child sit all the way back on the vehicle seat?
Does this just mean that the kid's hips are back by the seat bight (bite?) instead of forward (in order to bend knees?)

2. Are knees bent comfortably at the edge of the vehicle seat?
Is this an actual safety concern if the kid does #1? Like, theoretically, if you had a kid whose knees didn't bend comfortably, but they were older and mature enough that they didn't slouch, could they ride without a booster to avoid any stigma from friends? Not sure if it's possible for this to be the "last step" as I don't have a lot of experience with examining kids in car seats, but I am wondering.

3. Does seatbelt cross the shoulder properly? (it should be centered over the collar bone)
I have heard that it's not actually dangerous to have the shoulder belt not fit well, but that this step is important because if it's uncomfortable the kid will put it behind their back. I have heard the argument that even though shoulder belt fit is sub-optimal in a lot of adults, the reason that's acceptable is that an adult is mature enough not to put the belt behind their back. But if your kid is mature enough too, then can't they skip this step too? Shouldn't this step be "Will the child keep the shoulder belt in front of them even if it's not comfortable?" I can totally see this being the last step for some kids because it affects so many adults.

4. Is the lap portion of the seatbelt low – touching the thighs?
I am super confused about this one because I have heard that it not only needs to touch the thighs, but stay horizontal (so you can imagine balancing a cup of water on it? That's what I have read.) I have NEVER had a seat belt that does this (to my recollection). I have to make sure that I pull the lap belt snug so that it's against my hips and, yes, it touches my thighs a bit, but the belt is situated like a normal belt (wrapped around my hips like a low-riding clothing belt -- not like a napkin laid on my lap). Is it because I am overweight? Is this a big problem for my safety as an adult?

5. Can the child stay seated this way for the entire ride, every ride (awake and asleep)?
Just so we're clear, it IS possible for a kid to be ready for just the belt on some trips and need a booster on others, right? If you're just picking up your kid's friend for a sleepover you know your kid WON'T fall asleep, could they go without a booster if they pass the other steps?

Sorry, I just want to make sure I have this right. My kid is a little peanut and so I have a feeling that the particularities of these steps are going to be very important when she gets to the age when she doesn't want to be in the booster and all her friends are out of theirs. I just hope the incognito is still around when she's older!

Editorial rant to follow, yes, I generally do talk about the 5 step test to people who have no idea about boosters or seatbelts in general.....

I think a large portion of the 5 step test is to educate adults without talking down to them how to make sure a seatbelt is on right. Like, 'even if you've been doing it wrong all along, mom, this is how it's supposed to be done, I'm going to teach you so you get it right for your kid'. Most cars have relatively crummy belt fit, if you really get down to looking at every person in every seat, but the point is that there's something down on your pelvis (not flat on the thighs, sometimes people will say that when we are looking at booster pictures, but it's not necessary...on the pelvis, touching the lap, is fine), and something on your chest/shoulder to hold your body back.
I make my kids sit with their *butt all the way back, feet flat on the floor. That's slightly shorter than 5 feet and maybe age 10 for us in smaller cars, and more like 5 feet and age 11 in large captain's chairs. And then remind them to sit up when they want to lie too far sideways to sleep on long trips.
All their poorly educated friends unfortunately treat seatbelts as semi-optional and generally put them behind their backs, even now that they are well over 5 feet tall. I remind them as much as I can to buckle up properly, but too many years of mom allowing it wrong is hard to counter.

Hope that helps, I really like your post, very thoughtful analysis!


*this is a test that is incredibly easy for them to do themselves in any car, and it relatively guarantees that they won't be slouching down for leg comfort, which is what butt all the way back and knees bent at the edge is also trying to get across.

To put a simple answer to a not simple question - I believe the reason why adults do not need boosters has something to do with children's bones are not fully developed and are more fragile, therefore the booster makes the lap belt go across the strongest part of their hip bones, and helps to position the shoulder part to better distribute the force in an accident. With an adult we have stronger bones and a larger area so if the belt fit isn't perfect we have a better chance of it still doing it's job.

As to all your in depth questions I'm sorry but I honestly can't answer as I'm not a tech and my son is not even 2 yet.

In my opinion acceptable lap belt fit looks different on adults and children because their hips are different.

Caution-relevant oversharing and anatomy explaination
For example I am 22yo 5'5" and 110# a girl I know is 9yo 5'4" and 120#- the seatbelt needs to fit lower on her hips than mine because they are still growing and are still made partly of cartilage (go human anatomy class knowledge go!). My hips are fully developed and hard and bony the whole way through as well as I have a more pronounced illiac crests that help "catch" the lap belt.

The best way I have found to test lap belt fit (especially on kids I may not really know-therefore touching their hips a lot is in the "no-zone") is to pull the lap belt as tight as I can-if it hurts (indicating its on the belly) its too high.

Hope that helps!

I can't imagine how you would get a bunch of adults to go back into booster seats, I suspect is a large part of the problem. MOST adults fit OK. Those who don't tend to notice is especially when they are driving and many of those will sit on a pillow or some such so are effectively using a booster.

I wonder if that new Incognito seat is going to have a market among short adults.

I actually use the 5 step test in a different order. I do knees bent at edge (feet on the floor) first. Here's my exact speech.

2) OK sweetie, go ahead and hop in and sit on the seat so that knees bend and your feet touch comfortably, We don't want your legs going to sleep on you. (then I turn to the parents and say: if her feet are dangling in space and falling asleep, she will squirm around and slouch because no one can just put up with that)

*note for the OP, the legs HAVE to bend. The other alternative is that they stick out and that's not possible because the seat in front is in the way.

1) OK, now kiddo, I want you to lean your back forward so we can see behind you. (to parent: see how there is a gap behind her rear and the vehicle seat, this means that when she's leaning back, she's slouching. slouching makes the hip bones tilt back and lets the lap belt slide up too easily. OR See how there is no gap behind her hips and the seat, that means she can sit up straight without having to slide forward under the lap belt)

4) OK, now lets put the seat belt on. How does the shoulder belt feel to you? It's bothering your neck...or...oh, you usually put it behind you (then we talk about shoulder belt use) I point out that it needs to go on the shoulder, not the arm, and that if it's annoying your neck just a bit and you can ignore it, that's safe. I point out any adjustors in the vehicle itself. If the child is very skinny or the seatbelt anchor point is so far forward that it doesn't touch the child's sternum, I tell then that the only way around that problem is to use a booster until the child is big enough to fill out the space behind the shoulder belt.

3) Next step kiddo, take your two pointer fingers and put them on the pointy part of your hip bones. If you can't touch the bone without touching the seat belt too, that means you need to ride in a booster while you grow a little bit more.

(to parent: discuss booster options and objections to see if there is a way to alleviate some of the child's complaints)

5) Now, once you can pass all the steps, the real key is knowing if you can stay that way for the whole ride. Some kids want to fit so bad that they sit super stiff in order to pass all the steps. Well, cars bounce, and if you sit super stiff instead of adjusting to the bumps you get sore and tired really quickly. Before you know it, you'll be sitting all slouched and floppy and unsafe. Sometimes this works for the 5 minute ride to school, but think ahead and if you are going on a longer ride, especially a road trip where you are going to be sleeping, that's a good time to use a booster. Mom/Dad, this step is the one kids aren't very good at judging on their own. It's the kiddo's job to tell you when they think they fit so you can double check-and remember, different cars have different size seats, so she'll fit some before others-but it's your job to hold onto veto power and to know what their limits are. For my kids, they needed a booster for road trips for a good year after they fit the seat belt. They were super floppy sleepers, and of course they didn't know it because they were sleeping when they flopped.

Depending on time, I then tell the story of the time I thought my oldest was OK going to Disney (9 hour drive, at night) without a booster. It was such a disaster that 2.5 hours into the journey I stopped and bought a seat.




During puberty a hook shaped bony protrusion called the Illiac Crest develops on the pelvis. This catches the lapbelt and helps to prevent abdominal intrusion even with less than stellar fit. Even so, abdominal injuries are very common in adults because most adults have no idea how to wear a seat belt properly.

As far as the lap belt needing to be flat enough to balance a glass of water...I don't know where that came from. Even on children, the lapbelt doesn't need to be completely flat. In fact, it it is too far forward of the hips, the child can slide forward and pivot over the lap belt. The first year they did the booster fit comparison study, there actually was a booster that failed because the lap belt was TOO low and flat on the thighs. I also think that, even among those who know how a seat belt is supposed to fit, there is a tendency to look at the belly instead of the hips when testing fit. Unless you are super skinny, the seat belts in most cars are going to touch your belly, even if they fit correctly at the hip. This isn't a case of the belt being on the abdomen as much as it is a case of the abdomen causing a horizontal curve in the belt. As long as the hip bones are still above the top edge of the belt (and the wearer is not reclined to some crazy degree-or doing that man sitting thing), the worst the belly is going to get is some rub burns.

Speaking of man sitting...by far the most frustrating part of driving teenage boys is the fact that they are apparently physically incapable of using their buttocks for their intended purpose.

Safeinthecar, just what do you mean by man sitting? Just so I know what to look for either in DH or as my boys get (much) older .

Keeyamah said:

Safeinthecar, just what do you mean by man sitting? Just so I know what to look for either in DH or as my boys get (much) older .

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https://marketplace.secondlife.com/...?id=3703537&slug=Manly-Sit-Pose-tr-Copy-Trans

ETA: Indiana Jones http://laineux-barbouze.blogspot.com/2012/06/fathers-day.html

safeinthecar said:

https://marketplace.secondlife.com/p/Manly-Sit-Pose-tr-Copy-Trans/3703537?id=3703537&slug=Manly-Sit-Pose-tr-Copy-Trans ETA: Indiana Jones http://laineux-barbouze.blogspot.com/2012/06/fathers-day.html

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Ok, shockingly, DH doesn't sit that way unless he is in his office chair. In the car he's much better about it,but he (sadly) often doesn't wear his seat belt. He swears the fact that he was thrown from the car when he was a kid is what saved him, but he will wear it he is with the boys.

My mom isn't quite 60" and she sat on a phone book w/ a cushion behind her, for her first car back in the 70's. If they had booster seats back then, I'd bet she'd have sat on that instead! LOL Now, seats (we both have a Toyota) that go up higher and forwards more. So we can reach the clutch. I'm not a lot taller, but don't 5step in all cars...And, I think someone else answered the bone density/structure and development are different. Plus, many adults are over that 100# limit. LOL

tam

YinzerMama said:

I can't imagine how you would get a bunch of adults to go back into booster seats, I suspect is a large part of the problem. MOST adults fit OK. Those who don't tend to notice is especially when they are driving and many of those will sit on a pillow or some such so are effectively using a booster.

I wonder if that new Incognito seat is going to have a market among short adults.

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I cannot tell you how many cars I have sat in that I wish I had a booster for. I am 61", and struggle with seat belt fit in many cars. My mom had serious abdominal injuries from an accident when I was just out of college. She had to have surgery and was incapacitated for over a month. I remember going to parent/teacher meetings, etc in her place. Since then I have made it a point to ensure that I get the best fit I can in every car. But an adult booster would be such a help in some cars. Now, if there was only a way to keep the shoulder belt from riding across my boobs and up into my neck.

thtr4me said:

Now, if there was only a way to keep the shoulder belt from riding across my boobs and up into my neck.

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:yeahthatsad:YES. This is actually the worst part of belt fit for me. I always thought it was that I was too short, but no matter how I adjust the belt or my seat it seems like the problem is that the shoulder belt is getting interference from the boobs. Is there nothing that can help with this? Is this the "man" part of what they mean when I read that a seatbelt is designed for a man? Are the boobs the difference? Would it be possible to design a seat belt that fits better for a woman?

Nedra said:

:yeahthatsad:YES. This is actually the worst part of belt fit for me. I always thought it was that I was too short, but no matter how I adjust the belt or my seat it seems like the problem is that the shoulder belt is getting interference from the boobs. Is there nothing that can help with this? Is this the "man" part of what they mean when I read that a seatbelt is designed for a man? Are the boobs the difference? Would it be possible to design a seat belt that fits better for a woman?

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The thing that stopped it for me was getting a bra that fit really, really well. I'm...atypically thrifty...and tend to buy bras that fit close enough and are on sale instead of my actual size. Once I got a bra that fit correctly with the between the boobs part flush against my chest wall, the seat belt would stay in the middle.

Agree with the bra fit and even in the lower end bra's, a nice lift and moving them each to their 'corners' so to speak, helps a bit.
I'm a thin person (5'4") and my lap belt fit completely flat against my stomach but under my iliac crests, I actually thought this was how a belt should fit (for me) for a long time. I've been in 2 accidents and so far the only slight pain after (as far as seatbelt position goes) was my sternum and collar bone.


During the 5 step test, the butt needs to go all the way back and then assess if the knees bend and feet touch the floor. My 10 yr old was out of a booster for about 2 yrs before he went back in one. It just slowly faded out of the picture after a while. Then I had his sister and learned more about car seats and proper use, rtfm etc. So I purchased 2 nbb for him and he was fine with it. More recently there are comments (those are for babies, I haven't been in one since kindergarten) from his friend next door. Said friend is very small and needs a booster too but that's not my place, he does sit in one in my van though. Anywho, I dealt with his remarks by saying 'Safety isn't something to joke and laugh at. Adan is in a booster because it makes the belt fit him how it should. I care about his safety enough to make sure that every time he's in a vehicle, he is able to be a safe as he can, especially in an accident. I make sure the same for you when you come with us places. Boosters aren't for babies. His sister is 2 and not in a booster.' Then I got the my mom lost my booster and then the my mom can't afford one. Then my favorite lately is my 10 yr old and his friend both claim he can 5 step in his moms huge truck. I haven't checked it out but I don't see that being possible.

So that being said, I would not fudge the 5 step test to get my kid out of a booster so his friends won't see him in one. He is at the point where the incognito will be perfect since the other boosters seem to raise him pretty high and he is a couple inches from being out of one.

safeinthecar said:

The thing that stopped it for me was getting a bra that fit really, really well. I'm...atypically thrifty...and tend to buy bras that fit close enough and are on sale instead of my actual size. Once I got a bra that fit correctly with the between the boobs part flush against my chest wall, the seat belt would stay in the middle.

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My problem is that there is so much boobage right now (nursing mama), that there is no in-between so to speak .

thtr4me said:

My problem is that there is so much boobage right now (nursing mama), that there is no in-between so to speak .

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Bra I bought last week was a 34J. With the wrong bra (or even no bra) there's no in-between to speak of here either. Prior to a thread here on how to properly fit my daughter I was stuffing myself into a 38DDD and it might as well have been a sports bra with the uniboob I had going on. Really, it makes a huge difference in how your back feels too.