Car seats take up a lot of real estate in the back seat, so it is natural to want to move your child into a more compact booster seat as soon as it is safe to do so. Your child might also advocate for a big-boy seat rather than the "babyish" car seat. However, don't make the move too fast; car seats provide the best protection up to a certain age and weight. Your child needs to meet certain age, weight, height and maturity requirements before he is ready to move up to a grown-up seat.
Types of Boosters
Booster seats come in two types: backless and those that have a back. Booster seats with a back look more like regular car seats, and they provide a place for your child to rest his head. Booster seats with a back also help keep him confined in the seat. A disadvantage is that they take up almost as much space as a car seat. If you use a backless booster, your car's headrest must be above your child's ears. If it isn't, you need a booster with a back to protect your child's neck in a crash. Don't use a booster seat with a shield; shields do not provide enough protection. In a crash, the shield could cause your child to be ejected from the seat or the shield itself could injure the child. If you cannot remove the shield, buy another booster seat.
Sitting properly in a booster seat requires a certain level of maturity. Most booster seat manufacturers recommend not moving to a booster before age 4. Many states, including Alaska, Arizona, Colorado, Hawaii, Kansas, Louisiana, Mississippi, Missouri, New York, Ohio, Tennessee and Wisconsin list age 4 as the minimum age for using a booster seat. Before this age, your child might not be able to sit straight in the booster seat, and his neck muscles have not gotten strong enough to support his head adequately in a crash. Some states, including Arizona, Arkansas and New Mexico set age 5 as the minimum age for using a booster seat. In children age 4 to 8, booster seats reduce the risk of injury in children by 45 percent compared to using a seat belt only, according to a study published in the journal "Pediatrics."
Booster seats have different weight limits, but most use 40 pounds as the minimum weight for moving a child to a booster seat. All but two states -- Florida and South Dakota -- have regulations about booster seat use. Many states also provide a minimum weight that a child has to have before he can use a seat belt without a booster. In Kansas, New Jersey, North and South Carolina, North Dakota, Rhode Island and Wisconsin, a child must be at least 80 pounds before he can use a seat belt without a booster. Arkansas and Connecticut set the limit at 60 pounds, Delaware at 66 pounds, and Alaska and Mississippi mandate 65 pounds before a child can use the seat solely.
Some states use height requirements rather than age or weight requirements for booster use; some use all three. In many states, children must use boosters until they are between 8 and 12 years of age and have reached 57 inches, or 4 foot 9 inches, which is in accordance with recommendations from HealthyChildren,org, which is the official website published by the American Academy of Pediatrics. States with this ruling include Alaska, Arizona, California, Georgia, Hawaii, Maine, Maryland, Massachusetts, Minnesota, Michigan, New York, Oregon, Rhode Island, Tennessee, Utah, Washington, West Virginia and Wisconsin. To sit safely in an adult seat belt, your child's knees should bend at the seat's edge when sitting with his back against the back seat. If they stick out straight, he still needs a booster.