My 5 year old is around 3'8"/45 lbs. and still rides in his forward facing car seat, a Britax Marathon. Since he's getting older now, I want to put him in a booster seat instead. All of his friends are using them now (and have been for a few years). I'm not sure which is safer or if it even matters.

Any links to good research about this would be helpful. Thanks.

  • Well it looks like I'm easily looking at 6 years plus according to this new study. Article
    – Dennis
    Apr 8, 2011 at 19:41

5 Answers 5


The American Academy of Pediatrics recommends that once children transition from rear-facing seats, they should stay in forward-facing seats with a harness until they exceed the maximum weight or height for that seat. At that point, they should move on to a booster seat and shoulder belt.

For the Britax Marathon, this means your child should stay in it until he is either 65 lbs, or the maximum recommended height (couldn't find the height limit on their website).

  • My sons pediatrician said ALWAYS wait until your child hits the seat maximum.
    – Wayne
    Oct 10, 2014 at 20:32

I'd go by what the local DMV/State specifies.

NYS states:

Booster seats are for children who have outgrown convertible or toddler seats. Booster seats are for children who are four to eight years old, weigh 40 to 80 pounds, and are less than four feet, nine inches in height. You can use a booster seat until an adult seat belt correctly fits the child without use of the booster seat. Always use both the shoulder and lap belts with a booster seat. Never use only the lap belt with a booster seat.

TN law specifies (more fitting to your situation):

Children age four (4) through age eight (8), and measuring less than four feet nine inches (4'9") in height, must be secured in a belt-positioning booster seat system, meeting federal motor vehicle safety standards in the rear seat, if available, or according to the child safety restraint system or vehicle manufacturer's instructions. (Note: If the child is not between age four (4) and age eight (8), but is less than four feet nine inches (4'9") in height, he/she must still use a seat belt system meeting federal motor vehicle safety standards.)

Both results were found googling "booster seat [state]"


My 4 year old daughter and 3 year son are both in highback booster seats. Both my kids grew out of their old car seats really quick. Both of their car seats have head restraints to keep their necks safe from impact's.

Before I moved them to high back booster seats I talked to their pediatrician first. My daughter at 3 was at the height she needed to be for a high back booster seat. So I would talk to your pediatrician first.

But also it sounds like he wants to be in a big boy seat like the kids he knows. As far as safety the high back booster seat uses the seat belts and u loop them through the top of the seat and then over his shoulder and lap just like it does on you. My kids love their high back booster seats. Plus they are so easy to move from one car to another. Good luck.


Check your local laws. Car seat use long ago stopped being just about safety and began being about scoring legislative points. If you live anywhere in the US, these transitions are likely heavily regulated to the point that you don't actually have a choice in the matter.


Some sources say that there is no difference in safety between a booster and a car seat as long as they are used and fitted correctly. My sons pediatrician disagrees and says that having both shoulders secure gives better protection in side impact and roll over crashes (hence six-point harnesses in race cars). The NHSTA suggests using a car seat as long as possible (7 years old unless outgrown). The CDC makes the same suggestions and actually gives some numbers that support the statement of car seats being safer (variance of 9% between injury reduction of car seat vs booster).

Even with those suggestions, if your son is conscious of the fact he is still in a "little kid" chair and his friends are not then it may be best for him to move up to a side-impact rated Highback Booster.

Car Seats for Little Tikes
USA State law map

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