7 On Your Side: Consumer Reports shows how to keep kids safe, warm in car seats

Car seats are designed to keep children safe, but they only work if they're used properly. 7 On Your Side shows how to avoid one problem in the winter.

You may have seen the reports recently about the danger for children who wear puffy winter coats while buckled in their car seats. Consumer Reports says it is a serious concern, but there are easy ways to keep children safe.

In cold weather, there's a tendency for parents to bundle their children up to prepare them for the elements. But a bulky coat and a car seat can be a dangerous combination.

Consumer Reports' Emily Thomas says the harness might not be tight enough to secure a child in a crash.

With the help of 5-month-old Ben, she demonstrates a quick way to check if a child's coat is too big and bulky to wear under the car seat harness.

They first put Ben in his snowsuit and properly secure him into his car seat, so there was no slack in the harness straps. Then they removed Ben's coat and put him back in the seat to see how loose the straps were.

"So really, the snowsuit added this extra room. In the event of a frontal crash, all this extra room means that there's so much space for Ben to be able to ride up, and for his head to be outside the protection of his shell, which could mean he could have a head injury," Thomas said.

Parents can use the same test for bigger kids to see how much room their puffy coat puts between them and their harness.

"In addition to not wearing a coat, always make sure that your child is properly harnessed every time. You should not be able to pinch any fabric, and their chest clip should always be at armpit level," Thomas added.

To keep children safe and warm, Consumer Reports recommends first securing babies into their seat and then put a blanket on top of the harness. And for bigger kids, teach them a cool trick of wearing their coat over the harness for riding in the car.

Along with those tips, Consumer Reports suggests parents periodically go to a car seat checkup event to make sure the seat is properly installed.

Consumer Reports is published by Consumers Union. Both Consumer Reports and Consumers Union are not-for-profit organizations that accept no advertising. Neither has any commercial relationship with any advertiser or sponsor on this site.

(All Consumer Reports Material Copyright 2014. Consumers Union of U.S. Inc. ALL RIGHTS RESERVED.)