PHILADELPHIA (CBS) — In this frigid weather, a big, puffy coat may help you to stay warm. But it may make you less safe if you’re behind the wheel.

That bulky jacket may interfere with how well your seat belt works, says AAA Mid-Atlantic spokeswoman Tracy Noble.

“If you wear a seat belt with a puffy jacket and an impact occurs, the jacket compresses and it creates a gap between the passenger and the seat belt.”

And that gap, she says, is the same as wearing an ill-fitting belt. She says belts are best worn close, to reduce the body’s momentum at impact. For children, she recommends buckling kids in car seats without their jacket and then put their coat on backwards.

“So that the bulk is not behind them and the car seat is fitting them properly.”

AAA also recommends turning on the heat inside the car and wearing a light fleece as you drive.