Child Safety Seat Age
Like motorcycle and race car helmets, child restraints are tested for use in just one crash event. This means that if the restraint is compromised in any way (with or without the child in it), owners are strongly suggested to replace it. This is due to the uncertainty with how a compromised child restraint will perform in subsequent crashes.
There are two main types of boosters: high back (some of which have energy absorbing foam) and no back. A new generation of booster seats comes with rigid Isofix (Latch) connectors that secure to the vehicle's anchors, improving the seat's stability in the event of a collision.
The American Academy of Pediatrics says to “make sure the seat is at the correct angle so your infant’s head does not flop forward. Many seats have angle indicators or adjusters that can help prevent this. If your seat does not have an angle adjuster, tilt the car safety seat back by putting a rolled towel or other firm padding (such as a pool noodle) under the base near the point where the back and bottom of the vehicle seat meet.” Safety seats come with an instruction booklet with additional information on the appropriate angle for the seat.
In Australia there are six different types (Type A to Type F) of child restraints under the mandatory standard. Note: these restraints are NOT based on weight but on HEIGHT. All car seats with the AS/NZ1754 sticker will have height markers. These markers show clearly for what height the seat is appropriate.
Other car seats, also known as "booster seats," are required until the child is large enough to use an adult seat belt. This is usually, but not always, when the child is 1.49 (4ft 9in) tall. The child needs to meet five criteria before moving out of the booster seat, including the child's seating position, shoulder belt position, lap belt position, knee position, and ability to sit properly for the length of the trip.
For young infants, the seat used is an infant carrier with typical weight recommendations of 5-20 lb. Most infant seats made in the US can now be used up to at least 22 pounds (10.0 kg) and 29 inches (74 cm), with some going up to 35 pounds (16 kg). In the past, most infant seats in the US went to 20 pounds (9.1 kg) and 26 inches (66 cm). Infant carriers are often also called "Bucket Seats" as they resemble a bucket with a handle. Some (but not all) seats can be used with the base secured, or with the carrier strapped in alone. Some seats do not have bases. Infant carriers are mounted rear-facing and are designed to "cocoon" against the back of the vehicle seat in the event of a collision, with the impact being absorbed in the outer shell of the restraint. Rear-facing seats are deemed the safest, and in the US children must remain in this position until they are at least 1 year of age and at least 20 pounds (9.1 kg). although it is recommended to keep them rear-facing until at least 2 years old or until they outgrow the rear-facing car seat height and weight, whichever is longer.