EDINA, Minn. — Bundling up your kids during these cold months is second nature, but you might not know, too many layers could be dangerous.

Safety experts say car seat straps must be tight in order to work properly.

Thick winter coats can often get in the way.

“If you’ve got a really bulky jacket or coat on, you don’t know where that strap is, which could mean the strap is over the child’s arm and they could physically slide through,” Children’s Minnesota Chief of Pediatrics Dr. Gigi Chawla says.

Crash test studies show children can get ejected from their car seat if the straps aren’t tight enough.

Dr. Chawla says kids can also get injured by a “second impact” that happens when they slam into the straps that aren’t properly secured.

“Winter coats can create a gap between the child and their car seat strap, and that gap can cause an injury during a crash when the child slams into it,” Dr. Chawla says.

But with no winter coat, how then do you keep your kid warm this time of year?

"Once they're in their snuggly you can put their jacket on backwards, not zipped up in the back. You can also use some blankets over the top of their lap and on top of their body once they're firmly secured," Chawla says.

Parents can also run their cars for a few minutes to warm them up.

Yes, it's a few extra steps, but when it comes to safety, Chawla says you can't take the easy way out.

"It's really important to make sure that car seat is fitting really snuggly, because that’s how it works. With a gap or a lose fit your child can be in danger.”

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