Booster Seat FAQ

Booster seats are for children who are at least 4 years of age and too big for car seats, but are less than 8 years of age, unless they have reached 4'9" in height. Booster seats raise kids up so seat belts fit properly to protect them in a crash.

Seat belts are designed for adults, not for kids. Lap and shoulder belts reduce risk of injury and death by holding you into the car and spreading the energy of a crash over the strongest parts of the skeleton. Because seat belts do not fit well on many children, they can distribute crash forces over soft tissue, rather than bone, which can cause injuries to internal organs and spines. For children who have outgrown car seats but are not yet tall enough for seat belts alone, booster seats provide the best protection for young occupants and do the job of holding children securely in a vehicle and managing deceleration forces.

Children are ready for lap and shoulder belts alone when they can place their backs firmly against the vehicle seat back with their knees bent comfortably over the vehicle seat cushion. Lap belts should fit low and snug on the upper thighs and shoulder belts should rest over the shoulder and across the chest. For most children, that good fit is achieved by the time a child is 8 years old, or earlier if the child has reached 4'9".

How the seat belt fits on the child and how the child fits on the vehicle seat are more important measures of when a child is ready for a lap and shoulder belt alone than age or height. Belt geometry differs from vehicle to vehicle and you may find that your child can sit correctly in some vehicles but not in others (back against the seat and knees bent comfortably over the seat cushion, with the lap belt low and snug on the upper thighs and the shoulder belt resting across the shoulder and chest). Pay close attention to how the lap and shoulder belts fit in each vehicle your child rides in when making the transition from booster seat to seat belt.

Booster seats come in high-back and backless styles. The purpose of high-back boosters is to provide whiplash protection for children in seating positions without a headrest. If you have an older child who balks at using a booster seat or worries about what her friends might say, a backless booster can be a nice compromise, since it isn’t obvious to those outside the vehicle.

There’s a big difference physiologically between a 4'8" 7-year-old and a 4'8" 60-year-old. Prior to puberty, a child’s pelvis lacks an iliac crest—the thickened and expanded bone rim at the upper border of the ilium. In adults, this bony protuberance helps to hold the seat belt in place. Without an iliac crest, a seat belt can ride up onto a child’s abdomen instead of resting across the upper thighs. In a 4'8" grandmother—or even a 4'8" teenager—this would not be an issue.

Contact the Rainbow Babies & Children’s Hospital Injury Prevention Center’s Child Passenger Safety Hotline at 216-844-2277 and choose option #5 to leave a message with your phone number and your question or concern. Your call will be returned by one of Rainbow’s nationally certified child passenger safety technicians.