A winter coat can add a lot of slack in the car seat harness, perhaps as much as four inches! That’s plenty of room for a child to slip through the harness straps of their car seat and be thrown from the seat in a crash.

Coats that are too big or too long can also bunch up around the hip straps and crotch buckle and create potentially dangerous slack. Adults should also avoid wearing a puffy coat in the car, as this adds space between our body and the seat belt.

When a child arrives at our car seat fitting station, I try to anticipate whether what they are wearing is thin and light enough to be safely used. Sometimes it seems obvious, but I have been proven wrong when the parent/caregiver and I do this little test to see if the child can wear their jacket safely in the car seat:

  1. Place the child in the car seat with their jacket on. Snug up the harness and perform the pinch test. Your thumb and forefinger should not be able to pinch any of the harness material at the child’s shoulder.
  2. Remove the child from the seat without loosening the harness.
  3. Take the child’s coat off and put the him/her back in the car seat without adjusting the tightness, then buckle up the harness straps.
  4. Can you pinch any material between your thumb and forefinger? If yes, then the coat is too bulky to wear in the car seat.

How Do I Keep My Child Warm and Safe?

Use these ideas from the American Academy of Pediatrics (AAP):

Dress the child in thin layers.

Start with tights or leggings and a long-sleeved bodysuit or “onesie.” In very cold weather, long underwear is also a warm and safe layering option. Then add pants and a warmer top, like a sweater or thermal-knit shirt. Your child can wear a thin, well-fitting fleece jacket that stops at the waist over the top of the other layers. A very thindown coat may also be okay, although that has fooled me in the past when I did the 4-step test I mentioned.

Add hats, mittens, and socks or booties.

These help keep kids warm without interfering with car seat straps.

Use a coat or blanket over the straps.

You can add a blanket over the top of the harness straps. Or, put your child’s winter coat on backwards (over the buckled harness straps) after harnessing him or her snugly. Nothing should ever go underneath your child’s body or between the body and the harness straps.

What about accessories that go under the child, such as bundlers?

Like a heavy or bulky coat, a bundler also may add slack in the car seat harness. I have seen this demonstrated using the 4-step test method. Don’t use bundlers or any accessories in a car seat unless the item came from that car seat manufacturer. Follow the manufacturer’s instructions for use.

A car seat cover may be an option if it does not have a layer under the child. Make sure the cover does not affect the proper installation and use of the car seat, and that the child’s face stays uncovered to avoid trapped air and re-breathing.

How Can I Learn More?

For more information, see all of AAP’s Winter Car Seat Safety Tipsand the Safe Kids article Ask the Expert: Winter Coats and Car Seats. To learn more about child passenger safety, visit the UVM Medical Center’s Child Car Seat Safety website.

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