It is easy to think that there is nothing wrong with bundling a baby or toddler up in their winter gear before bucking them into the car seat. Perhaps you even think that is the exact right thing to do. You are, after all, keeping them warm – and it is much easier than undressing them before buckling and then redressing them when you arrive at your destination… However, doing so is extremely dangerous.

According to Car Seats For The Littles, a community of car seat technicians: “For your child’s car seat to offer the maximum protection in a crash, the harness or seat belt needs to be as close to the child as possible. The more layers of padding or clothing between a child and the harness, the harder it is to properly fit the restraint to the child. The harness can end up fitting to the thick coat, and in the event of a crash, all that extra air is forced out between the layers, leaving the harness too loose to protect a child. A loose harness, at best, means extra crash time on the child, and at worst, could mean ejection from the seat. This principle also applies to children riding in boosters and adults in seat belts.”

The Car Seat Lady recommends the following to keep your child warm in the car without wearing a bulky coat:

• Put the coat on your child, sit them in the child seat and fasten the harness. Tighten the harness until you can no longer pinch any of the harness webbing with your thumb and forefinger.
  
  
• Without loosening the harness, remove your child from the child seat.
  
  
• Take the coat off, and put your child back in the child seat and buckle the harness straps, which are still adjusted as they were when he was wearing the coat.
  
  
• If you can now pinch the webbing between your thumb and forefinger, then the coat is too bulky to be worn under the harness.