Car Seat Safety: When is it safe to use a booster seat or seat belt?

In her final installment for us on car seat safety, CBB reader Andrea gives an overview of when it is safe to transition your child from a harnessed seat to a belt-positioning booster seat.  She also offers guidance on when your larger child can safely use the adult seat belt, only. 

by CBB Reader Andrea, Certified Child Passenger Safety Technician (CPST)

Once your child moves to a belt-positioning booster seat, he or she should use it until the adult seat belt fits properly.  With a booster seat, the shoulder belt should be snug against the child’s chest, resting across the collar bone.  The lap belt should lay low across the child’s upper thigh area.

Seat belts are designed to protect adults and older children, and they must fit correctly in order to do that.  According to SafeKids USA, looking at current vehicle designs, child growth patterns/charts, and general lessons learned through observation, many advocates have concluded that vehicle safety belts don’t fit until kids are 8, 9, 10 or even 11-years-old.  The child in the picture at the right is 7-years-old, seated in a popular family vehicle, and the seat belt doesn’t even come close to fitting properly.  The next picture illustrates how a booster improves the fit of both the lap belt and the shoulder belt.

Children who use seat belts before they fit properly are at risk of internal organ and spinal column injuries.  Children in a 2001 PCPS study who were ‘suboptimally restrained’ were at greatest risk for injuries known as ‘seat belt syndrome.’  These injuries can include severe bruising as well as serious injuries (including laceration) of the intestines, kidneys, stomach and other organs.  A shoulder belt that crosses a child’s neck also puts the child at risk of neck injuries.

Click ‘continue reading’ for more. 

Children’s Hospital of Philadelphia says that all children who have outgrown harnessed car seats should be properly restrained in a booster seat until they are at least 8-years-old, unless they are 4’9" tall first.  At a presentation to Child Passenger Safety Technicians and instructors in February, Miriam Mancy of University of Michigan Transporting Research Institute said that a recent study involving children aged 4-8 showed that all achieved a better seat belt fit with a booster, even kids taller than 4’9", which is the height that even states with booster seat laws allow children to ride in seat belts. 

A backless booster is safer than seat belt-only, and a high-back booster provides even more protection.  Many models offer side impact protection for the child’s head.  They also position the belt over the child’s upper body better than a backless will.  In addition, if used in a vehicle seat that does not have headrests, it’s extremely important that a child have the head support provided by a high-back booster — this is what will protect the child from whiplash in the event of a crash.

Do not use a belt positioner device. These devices actually pull the lap and shoulder portions of the seat belt onto the vulnerable areas of the chest and abdomen.

So when IS your child old enough/big enough to use just the vehicle seat belt? There is no magic age, height or weight.  The National Highway Traffic Safety Administration (NHTSA) has developed a set of guidelines to help parents and caretakers determine when a child can safety use the vehicle seat belt.  If your child meets ALL of these guidelines, then he or she can safely use the vehicle seat belt.  If one or more of these guidelines is not met, your child should continue to use a belt-positioning booster (such as the Graco TurboBooster, pictured right in Beignet, or the Britax Monarch, pictured at the top of the post in Red Racer, or Parkway) or a harnessed seat.

• Does the child sit all the way back against the auto seat?
• Do the child’s knees bend comfortably at the edge of the auto seat?
• Does the shoulder portion of the seat belt cross the shoulder between the neck and arm?
• Is the lap portion of the seat belt as low as possible, touching the thighs?
• Will the child stay seated like this for the whole trip?

Related videos:

• Crash test illustrating how ‘seatbelt syndrome’ can occur.
• GM booster video.

What did you think of this series on car safety for children?

Comments

I think it’s fantastic that you’re posting this important safety information. Thank you!

- SM on May 29th, 2008

Great article, really informative. It would be great if you could archive this into a category called safety or something, it is a great reference.

- Car on May 29th, 2008

My son is 5 and rides in a tripped out (I sewed racing and flame patches to it) Britax Regent. We had the Britax Monarch Racer and after 2 days I returned it. The seat was so heavy and floppy, and for it to not be secured to the seat with a latch or anything felt very unsafe. I have always been the car seat warden with my friends and family and have owned a few britax, and a sunshine kids seat. My truck is a Chevy Trailblazer and the Monarch Racer they have pictured was a terrible fit to my truck’s rear seat. Anyway, I did not jump on here to talk bad about it, I truly wished it worked but I feel so much safer with my son in the harness, though he would much rather a regular booster and seat belt lol I am curious though why boosters are not tethered to the car like a car seat. Wouldn’t it make less of an impact on the seatbelt in the event of a crash? As of now the seatbelt has to hold the child in place as well as the booster.

- Heather on May 29th, 2008

They do in fact have a handful of latchable boosters:

Sunshine Kids Montery – latchable
Graco Nautilus – latchable during booster stage (for harness latchable limits, see car and carseat manual for limits)
Britax Frontier – latchable during booster state (for harness latchable limits, see carseat and car manual for limits)
Recaro Young Start – Tether strap – no latch – but top strap available.

I’m sure we will see more of these come to market, as it’s a great way to keep the booster tied down while not in use, and keeps it from shifting around. Latch has limits when being used with harness because the weight of the child is pulling on the latch bars – but in booster mode, the latch bars do not feel the impact, the seat belt does.

- Kate on May 29th, 2008

Here in Europe, accordind to the European Union law kids have to use car seat until they’re 1.50 metres tall or 12 years old (because there are 12 year-olds taller than that)…I think that’s about 4 feet, 11 inches tal…

- Ana on May 29th, 2008

would like to know if you have any safety data on the Volvo’s that come with built-in booster seats?

- jeane blumenthal on May 29th, 2008

I think what you guys are doing is great. I just emailed this info to a friend that has his 2 year old in a booster seat. Keep up doing this. I really think you should have her write about all the after market items like the bundle mes and head rests that are seen in car seats. Also the things in Dennis Quaid’s car seats for his babies. Many people think because celebritys have them they are safe and ok to use.

- Kristin on May 29th, 2008

My 4 1/2 year-old daughter is still in her Britax Marathon car seat. The reason we bought that for BOTH of our kids is because it is supposed to eliminate the need for buying a separate booster seat. My daughter still fits perfectly in it and I feel like she is much safer in it than a booster seat.

- Kate on May 30th, 2008

Kate- thanks for the info!!

- Heather on May 30th, 2008

Kate – the Marathon will not eliminate the need for a booster… after the Marathon is outgrown, your child will need one or even another harnessed seat (like the Regent, Nautilus, or Radian), depending on the age and size.

Heather – Booster seats originally all tested better if they were allowed to move WITH the child… that is why. Now, Heavier boosters like the Recaro start, for instance, which are more common outside the US, do typically have a top tether or Latch attachments.

But in the US, it has only been since companies have designed boosters to pass the tests as well as they do without these attachements that they have been introduced to the market.

Even so, the REASON for attaching them was not to increase safety for the child in them, but to prevent the booster becoming a projectile when it is not occupied.

Most people do not buckle their booster seats when no one is in them, but if they are not able to be attached by latch to the car, then that is exactly what needs to be done.

That said, of course, your 5yr old is safer in a harnessed seat until it is outgrown.

Oh… and the Sunshine Kids Monterey, which is latchable, also is the tallest booster on the market, though it is not a narrow booster, so may not fit in every seating situation… aka… may not be good for doing 3 across.

Andrea – another great article!!

- Kat on May 31st, 2008

my 6yr old is 4ft8 and 73lbs

- rick on July 31st, 2009