Car Seat Safety: When to Move to a Booster

on January 29, 2009 at 7:13 AM

Not ready for the booster yet!

"My daughter is 33 pounds and 36 inches and will be 2 next week. She is getting tall for her seat and there isn't much more of the belt I can let out to fit her shoulders. Would a high-back booster seat that is for 30-80 pounds be okay?"

"My daughter just turned 4 and she is small for her age. She is normal height but only weighs about 29 pounds. I was wondering about moving her to a booster seat ... maybe one with a harness?"

"My 2 year old daughter weighs about 35 pounds and is around 35 inches tall. The booster seat box says that she has to be 35 pounds and 37 inches. I am a little scared to put her in it. When did you switch your toddler from a 5-point harness to a booster seat?"

It's one of the most commonly asked car seat questions on CafeMom. So here's CarSeatJunkie, a CafeMom to a 3 and 6 year old, certified child passenger seat technician, and administrator of the Car Seat Safety group, to set us straight on the famous 4 years and 40 pound rule for when it's safe to move toddlers to the next travel stage:

CafeCynthia: Could you explain the 4 years and 40 pound rule?

CarSeatJunkie: The rule means that a child should be 4 years old AND 40 pounds before moving from a 5 point harness to a belt-positioning booster seat. So, the child should meet BOTH criteria, not one or the other. But there are exceptions -- see below.

Where did the rule come from, anway?

It's not a federal or state law -- as technicians, we recommend it because there needs to be a certain amount of maturity that comes with sitting properly in a booster seat. The 40 pound thing is the "general" weight limit on most commonly used car seats, and that's the age when most kids would be transitioned to a booster. (Some do have higher weight limits, in which case it's much safer to leave your older toddler in the 5-point harness.) But there are always exceptions.

Can you give me an example?

Say a 2 year old is 40 pounds. I always tell the parent that I would recommend a higher harnessing (5-point) weight seat -- one that will go up to 65 or even 80 pounds.

Having two children myself, I found that neither one were mature enough to sit in the correct position in the booster.

What is that "correct" position?

The child needs to sit with their bottom and back all the way back in the booster with the seat belt lying across their shoulder/chest properly and the lap portion across their upper lap/hip bones. They need to be able to stay in this positon for the entire ride.

You also need to read the suggestions on the individual booster seat you are considering for your toddler. For example, the Graco TurboBooster with the highback is designed for children ages 3 to 10 and 30 to 100 pounds, so putting a 2 year old child in that seat -- even if they weigh 30 pounds -- goes against those guidelines.

In addition, the seat belt should lie as flat and as close to your child's body as possible to eliminate any slack so your child won't move forward as much during a crash. Twisted belts not allowed!

If my child is 4, 40 pounds, and mature enough to sit properly in a booster, can I skip the high-back booster and go right to the backless?

Researchers have not found a big difference between the two in crash tests. However, if your toddler consistently falls asleep, a high-back booster will help keep him in the proper position, rather than leaning on the door panel or falling completely out of the seat belt. A high back also offers side impact protection.

These are just guidelines, ladies. You need to pull out your car and child seat manuals for the proper weight limits and instructions for installing and using your seat. And, if you can, ask a certified car seat technician to check your work.

++Is your toddler in a belt-fastening booster seat? Did you follow the 4 year AND 40 pound rule?

About the author Cynthia Dermody

is The Stir's Managing Editor who has trophies in her home for her skills at the Irish Jig. She makes cupcakes with as many fattening ingredients as possible, doesn't comb her hair for months at a time, and was probably a faerie in a former life.

Filed Under: car seat safety

Comments (21)

AustinsMommy124

on Jan 29, 2009 at 8:42 AM

What spot in the back seat is best for the toddler carseat? Would a side be better than the center? If so, would the back passenger be better than the back driver??

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emptynestmom456

on Jan 29, 2009 at 8:59 AM

My poor 3 yr. old gd has to sit in one of those harnessed car seats and she can't hardly move. I hate it. Then when I try to fasten the strap in between her legs, I end up pinching her legs in the buckle!!

hurleydoll18

on Jan 29, 2009 at 9:21 AM

What seat do you have her in? It is possible that she has outgrown the harness on the seat so she'll need to be moved to higher weight harnessing seat like the Graco Nautilus. If you have a seat that harnesses to only 40lbs, it is very likely that she has outgrown the harness in height since most children outgrow these seats around 3-4 yrs old

on Jan 29, 2009 at 9:23 AM

Statistically, the middle position is the safest position in the vehicle but only if you are able to get a rock solid install in the middle position. This isn't always possible in some vehicles so the safest position is the one where you can get the best install. If that is the middle, then go with that. If you get a better install on an outerboard position, then go with that. It doesn't matter which side you put the child on, it has been shown that there is very little to no difference in safety between the passenger and driver side.

NorahSethsMommy

on Jan 29, 2009 at 9:27 AM

Here kids have to be 40lbs and 4 years to switch to booser, but I jsut dont feel this is safe. My kids will stay in their 5 point harness carseats as long as they fit in them. Thei safety in an accident is more important to me than convienence.

Angiebooboo

on Jan 29, 2009 at 9:45 AM

what is safer for a child a car seat or booster seat .

Cafe Melisa

on Jan 29, 2009 at 10:18 AM

I think this is so helpful! With 2 kids right around these ages/weights, this booster seat question has been on my mind. Thank you Cafe Cynthia!

JPsMommy605

on Jan 29, 2009 at 10:24 AM

I didn't follow the 4 yrs and 40 pounds - I followed the "he's mature enough", "he's tall enough", "he's heavy enough" guidelines. I switched my son to a high back booster seat after he turned 3 - he was already 40 pounds and about 40 inches. The strap fits over his shoulder and he understands that there is no stretching, bending or re-positioning while I'm driving. He also buckles himself in and makes sure it's on correctly. He also follows all rules like no unbuckling until the engine stops and the engine doesn't start until we're all buckled in. I know accidents can happen, but as with the rest of my life, I chose to not restrict my choices because "sometehing could happen" - true, but we could also get hit by a car while walking on the sidewalk. My son is mature enough and desires independence enough that a booster set was our choice.

LelandsMommy

on Jan 29, 2009 at 10:54 AM

I still don't know what to do with my almost 3 year old. He is 35 lbs nd 37 inches tall. I have him in his 5-point harness still and it has an 80 lb weight limit, which I thought whould last him a looooonnnngggg time. But the thing is so small! It's narrow, and he has to hunch his shoulders forward to be able to sit back in the thing. I've also used up almost all of the belt, and I STILL keep pinching his legs when I buckle him in.