Car seat safety isn't child's play. Understand 10 common mistakes parents make when installing and using car seats.

Car seat safety is crucial for protecting your child during travel, but knowing how to safely buckle up your child as he or she grows can be difficult. Check out 10 common mistakes parents often make when it comes to car seat safety — and how to avoid them.

If you're considering a used car seat for your child, make sure the car seat:

  • Comes with instructions and a label showing the manufacture date and model number
  • Hasn't been recalled
  • Isn't expired or more than 6 years old
  • Has no visible damage or missing parts
  • Has never been in a moderate or severe crash

If you don't know the car seat's history, don't use it.

The safest place for your child's car seat is the back seat, away from active air bags. If the car seat is placed in the front seat and the air bag inflates, it could hit the back of a rear-facing car seat — right where your child's head is — and cause a serious or fatal injury. A child who rides in a forward-facing car seat could also be harmed by an air bag.

If it's necessary for a child to travel in a vehicle with only one row of seats, deactivate the front air bags or install a power switch to prevent air bag deployment during a crash.

If you're placing only one car seat in the back seat, install it in the center of the seat — if a good fit is possible — rather than next to a door to minimize the risk of injury during a crash.

A car seat is designed to protect your child during travel. It's not for use as a replacement crib in your home. A 2009 study showed that sitting upright in a car seat might compress a newborn's chest and lead to lower levels of oxygen. Even mild airway obstruction can impair a child's development.

Sitting in a car seat for lengthy periods can also contribute to the development of a flat spot on the back of your baby's head and worsen gastroesophageal reflux disease (GERD) — a chronic digestive disease. In addition, a child can easily be injured by falling out of an improperly used car seat or while sitting in a car seat that falls from an elevated surface, such as a table. Although it's essential to buckle your child into a car seat during travel, don't let your child sleep or relax in the car seat for long periods of time out of the car.

Before you install a car seat, read the manufacturer's instructions and the section on car seats in the vehicle's owners manual. Make sure the seat is tightly secured — allowing no more than 1 inch of movement from side to side or front to back when grasped at the bottom near the attachment points — and facing the correct direction.

If you're using an infant-only seat or a convertible seat in the rear-facing position, keep these tips in mind:

  • Use the harness slots described in the car seat's instruction manual, usually those at or below the child's shoulders.
  • Place the harness or chest clip even with your child's armpits — not the abdomen or neck. Make sure the straps and harness lie flat against your child's chest and over his or her hips with no slack.

Position the car seat's carrying handle according to the manufacturer's instructions.

In the rear-facing position, recline the car seat according to the manufacturer's instructions so that your child's head doesn't flop forward. Many seats include angle indicators or adjusters. You can also place a tightly rolled towel under the seat's front edge to achieve the right angle.

To prevent slouching, place tightly rolled baby blankets alongside your newborn. If necessary, place a rolled washcloth between the crotch strap and your baby to prevent slouching. Don't use any additional products unless they came with the car seat or from the manufacturer.

Resist the urge to place your child's car seat in the forward-facing position just so that you can see his or her smile in your rearview mirror. Riding rear facing is recommended until a child reaches age 2 or the highest weight — typically at least 35 pounds (about 16 kilograms) — or height allowed by the car seat manufacturer. You can start with a convertible seat, which can be used rear facing or forward facing and typically has a higher rear-facing weight and height limit than does an infant-only seat, or switch from an infant-only seat to the convertible variety as your baby grows.

When your child reaches age 2 or the rear-facing weight or height limit of the convertible seat, you can face the seat forward. When you make the switch:

  • Install the car seat in the back seat according to the manufacturer's instructions, using either the seat belt or Lower Anchors and Tethers for Children (LATCH) system.
  • Use the tether strap — a strap that hooks to the top of the seat and attaches to an anchor in the vehicle — for extra stability.
  • Adjust the harness straps so that they're threaded at or above your child's shoulders. Make sure the harness fits snugly.

Harness straps might not provide enough protection over a baby's bulky outerwear. If it's cold, dress your baby in a lightweight jacket and hat. Buckle the harness snugly and then tuck a blanket around your baby for warmth. Save the bulky outerwear for outdoors.

Older children need booster seats to help an adult safety belt fit correctly. You can switch from a car seat to a booster seat when your child has topped the highest weight — typically 40 to 80 pounds (18 to 36 kilograms) — or height allowed by the car seat manufacturer. Remember, however, that your child is safest remaining in a car seat with a harness for as long as possible.

Booster seats must be used with a lap and shoulder belt — never a lap-only belt. Make sure the lap belt lies low and snug across your child's upper thighs and that the shoulder belt crosses the middle of your child's chest and shoulder.

Some booster seats come without backs. Backless booster seats also must be used with a lap and shoulder belt — never a lap-only belt. If your vehicle has low seat backs or doesn't have a headrest to protect your child's head and neck in a crash, consider using a high-back booster that fits your child's height and weight.

Most kids can safely use an adult seat belt sometime between ages 8 and 12. Here's how you'll know that your child is ready:

  • Your child reaches a height of 4 feet 9 inches (nearly 1.5 meters).
  • Your child sits against the back of the seat with his or her knees bent comfortably at the edge of the seat — and can remain that way for the entire trip.
  • The lap belt rests flat and snugly across your child's upper thighs, and the shoulder belt rests on the middle of your child's shoulder and chest — not on the neck or face.

Make sure your child doesn't tuck the shoulder belt under his or her arm or behind his or her back. Remember, the back seat is the safest place for children younger than age 13.

If you have questions about child passenger safety laws or need help installing a car seat, participate in a local car seat clinic or inspection event. You can also check with the National Highway Traffic Safety Administration for help finding a car seat inspection station.

Aug. 16, 2014