Parents everywhere bring out their babies’ winter coats or snowsuits to keep baby warm during travel. However, thick winter coats or snowsuits can compromise your child’s car seat safety.
In order for a baby car seat or toddler booster seat to function properly, the straps need to remain tight against the child’s chest.
Many companies offer thick car seat covers that act like a bunting for babies in the winter.
Parents should avoid buying any car seat cover or infant bunting that threads through the harness straps of their child’s car seat. Often the packaging of these covers states that the product meets all federal car seat safety guidelines. However, there are no federal guidelines governing after-market car seat accessories.
From: About.com: Baby Products