A booster seat is necessary when a child has outgrown his forward-facing car seat, but is too small to use a seat belt alone. Vehicle seat belts are designed to protect the average-sized adult; therefore booster seats are necessary until a child reaches between 80 and 100 lbs. and a height of 4 feet, 9 inches. By properly positioning a child in the vehicle, booster seats decrease the risk of injury in a motor vehicle crash.
Function
It's time to move a child from her forward-facing car seat to a booster seat when: she's reached the manufacturer's weight or height limit for the seat, the tops of her ears have reached the top of the seat, or her shoulders are above the level of the top harness slots on the seat. Unlike a child or infant car safety seat, a booster seat does not have a harness of it's own, but makes the vehicle's lap and shoulder belt system fit properly for a child.
Types
There are two types of booster seats available. The first is a high-back, or belt-positioning booster seat. This type of seat has a back and headrest that provides support for the head and neck in a crash and is designed for use in vehicle seats that do not have a head rest. Some forward-facing car seats will also convert to a belt-positioning booster by removing the harness. The other type of booster has no back, and is designed for use with vehicle seats that have a built-in head rest.
Installation
When using any type of booster seat, it is vital to follow the manufacturer's instructions carefully. The booster should be placed in the back seat of the vehicle in a spot that has both a lap and shoulder belt available. See the Resources section for a link to an instructional video from the National Highway Traffic Safety Administration.
Effects
Motor vehicle crashes are the leading cause of death in children ages 3 to 14 years old. The United States Centers for Disease Control reports that use of booster seats reduce the risk of injury by 59 percent compared to using only seat belts alone in children between the ages of 4 and 7 years.
Considerations
Booster seat usage is largely affected by parents' attitudes about vehicle safety. While parents may intend to use booster seats consistently, in practice they do not always follow through. Many states require children to use a booster seat until they reach a specified age, height or weight. These laws can vary from one state to another, so it's important to check your state's requirements.
