Is your child wearing a puffy coat in the car seat? Experts say you're doing it wrong.

Puffy coats are meant to keep little ones warm, but some public safety experts say they may actually be working against kids and increase their chances of getting hurt during car crashes.

Injuries could include head, neck or upper extremity injuries, safety experts say. And while some parents think puffy coats act as extra protection or cushion, they don't.

Gina Duchossois, an injury prevention manager at the Children's Hospital of Philadelphia, said car seat harnesses should fit snugly. When a child is strapped into a car seat while wearing a coat with lots of filler, the harness isn't properly fitted to their body.

"In a crash, a lot of times that puffy jacket – or whatever that thick fabric is – can compress, and then leave a lot of extra movement of that child within the harness system," she told USA TODAY.

Experts say it's hard to find statistics about the impact of coats on car seat effectiveness, but according to the CDC, 607 U.S. child passengers ages 12 and under were killed in motor vehicle crashes in 2020; more than 63,000 were injured. Of the children killed in crashes, 38% weren't buckled in.

And according to a 2011 study from the National Highway Traffic Safety Administration, about 46% of car seats and booster seats are used incorrectly in a way that could make them less effective; misuse included improper belt positioning, loose installation, and loose harnesses, among others.

To prevent injury, child safety experts suggest parents put kids in the car and take their coats off. They can then strap the children into their seats and put the coat over them backwards – either like a blanket or with their arms inside the sleeves.

But for parents who don't want to take their child's coat on and off between trips, hoodies, light jackets, blankets, and even coats designed specifically for car seats could be options.

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Which coats are too thick?

Duchossois usually tells parents to watch out for down coats and other jackets with lots of filler.

"That would be a good indication that that coat is just going to be too thick to use within the harness system," she said. "Just make sure that it's on the thin side or a thinner coat when putting the child in the car seat with the harness."

The less the child moves in their car seat during a crash, the more the car seat will work like it's supposed to. That decreases the chance for injuries, said Cass Herring, Director of Child Occupant Protection for Safe Kids Worldwide, a certifying body for child passenger safety technicians.

And if taking coats on and off between car rides is too much, parents could consider layering, she said.

"Let's think about an infant," she told USA TODAY. "If you have a onesie and then maybe you have a fleece underneath that's not too thick, then that's going to be perfect. As soon as you get in the vehicle and warm the vehicle up, you don't want them to have too many layers."

The pinch test

If you're not sure whether your child's coat is too thick for their car seat, there's a pinch test you can do, Herring said.

It goes like this:

  1. Put the coat on your child and put the child into the car seat.

  2. Buckle up the harness and tighten it.

  3. See if you can pinch the harness straps at the child's shoulder.

  4. Take the child out of the coat.

  5. DO NOT adjust the harness.

  6. Put the child back in the seat.

"If there is space between the child and the harness, then that means that coat is probably too bulky," Herring said.

Lighter jackets and hoodies are also options, she said.

There are also coats designed specifically for car seats, like Buckle Me Baby Coats. Child passenger safety technician Dahlia Rizk started the company in 2017.

Her coats are made with velcro and designed so that they split at the seam on the child's shoulder.

"When you pull that front panel up out of the way, there's no coat material on the shoulders and there's no coat material on the chest," Rizk told USA TODAY. "When you put the harness on, the harnesses is directly on the chest and shoulders."

The National Highway Traffic Safety Administration doesn't set standards for coats, but also said heavy puffy coats with too much bulk can add extra room and cause a loose fit in car seats.

How big should my kid's car seat be? Which direction should it face?

Duchossois from the Children's Hospital of Philadelphia stressed choosing a car seat that's age, height and weight appropriate, and making sure car seats are facing the correct direction.

Car seat manufacturers set height and weight limits, which are easy to find on stickers on the seats, she said.

According to the National Highway Traffic Safety Administration, infants should have rear-facing car seats only and usually outgrow them before their first birthdays. After that, the NHTSA recommends guardians buy convertible or all-in-one car seats and use them rear-facing.

Kids typically graduate to booster seats somewhere around ages five or six, Duchossois said. They're normally ready for regular seating between ages 8 and 12, but again, it depends on the child's size.

"Don't rush to move your child from rear-facing to forward-facing, or from forward-facing to a booster seat," Duchossois said. "Make sure you're looking at your car seat so you know that your child's fitting within those specific height and weight limits."

Saleen Martin is a reporter on USA TODAY's NOW team. She is from Norfolk, Virginia the 757 and loves all things horror, witches, Christmas, and food. Follow her on Twitter at @Saleen_Martin or email her at sdmartin@usatoday.com.

This article originally appeared on USA TODAY: Can kids wear puffy coats in car seats? No, safety experts say