All infants and toddlers should ride in a rear-facing car safety seat (CSS) until they are 2 y of age or until they reach the highest weight or height allowed by the manufacturer of their CSS.
Infant-only seats usually have a handle for carrying and can be snapped in and out of a base that is installed in the vehicle. They can only be used rear-facing. Convertible CSSs can be used either forward- or rear-facing and typically have higher rear-facing weight and height limits than infant-only seats.
When children using infant-only seats reach the highest weight for their seat, they should continue to ride rear-facing in a convertible seat for as long as possible. Most currently available convertible seats can be used rear-facing to at least 35 lb.
Combination CSSs are seats that can be used forward-facing with a harness system and then, when the child exceeds the height or weight limit for the harness, as a booster seat with the harness removed.
All children 2 y or older, or those younger than 2 y who have outgrown the rear-facing weight or height limit for their CSS, should use a forward-facing CSS with a harness for as long as possible, up to the highest weight or height allowed by the manufacturer of their CSS.
Several models of convertible and combination CSSs can accommodate children up to 65 or 80 lb when used forward-facing. The lowest maximum weight limit for currently available forward-facing CSSs is 40 lb.
All children whose weight or height is above the forward-facing limit for their CSS should use a belt-positioning booster seat until the vehicle lap-and-shoulder seat belt fits properly, typically when they have reached 4 feet 9 inches in height and are between 8 and 12 y of age.
There is a safety advantage for young children to remain in CSSs with a harness for as long as possible before transitioning to booster seats.
When children are old enough and large enough to use the vehicle seat belt alone, they should always use lap-and-shoulder seat belts for optimal protection.
Booster seats function by positioning the child so that both the lap and shoulder portions of the vehicle seat belt fit properly; the lap portion of the belt should fit low across the hips and pelvis, and the shoulder portion should fit across the middle of the shoulder and chest. They come in both high-back (a seat back that extends up beyond the child's head) and backless models. The lap portion of the belt should fit low across the hips and pelvis, and the shoulder portion should fit across the middle of the shoulder and chest when the child sits with his or her back against the vehicle seat back. If they do not, then the child is likely too small to use the vehicle seat belt alone and should continue to use a belt-positioning booster seat.
All children younger than 13 y should be restrained in the rear seats of vehicles for optimal protection.
CSSs should be installed tightly either with the vehicle seat belt or with the LATCH system, if available. LATCH is a system of attaching a CSS to the vehicle that does not use the seat belt. It was designed to ease installation of the CSS. Whether parents use LATCH or the seat belt, they should always ensure a tight installation of the CSS into the vehicle.
LATCH indicates lower anchors and tethers for children.
Explanations of Decision Points and Additional Resources
Children with certain temporary or permanent physical and behavioral conditions such as altered muscle tone, decreased neurologic control, skeletal abnormalities, or airway compromise may preclude the use of regular CSSs and may require the use of regular CSSs may require specialized restraint systems.
Infants younger than 2 y have relatively large heads and several structural features of their neck and spine that place them at particularly high risk of head and spine injuries in motor vehicle crashes. Rear-facing CSSs provide optimal support to the head and spine in the event of a crash, and evidence indicates that this benefit extends to children up to 2 y of age or longer.
Children who are 2 y of age or older and small for age may need to be evaluated like children younger than 2 y. Consult a child passenger safety technician with enhanced training in special needs or other resources for assistance.
The AAP annually updates information on child restraint systems currently available in the United States (http://aap.org/family/carseatguide.htm). More recent products have higher weight limits and should be used when possible. In general, children should remain in a child restraint system until they outgrow the weight or height limits for its intended use.
Most children 2 to 8 y of age are not large enough to fit properly in the vehicle seat belt and will require a CSS or booster seat for optimal restraint. A belt-positioning booster seat positions a child so that the lap and shoulder portions of the seat belt fit properly: the lap portion low across the hips and pelvis and the shoulder portion across the middle of the shoulder and chest.
Most children shorter than 4 feet 9 inches in height will not fit properly in vehicle lap-and-shoulder seat belts.
These 3 questions are an evaluation to determine whether a child is ready to be restrained by the vehicle seat belt without a booster seat. If the answer is “no” to any of these questions, the child should use a booster seat:
Is the child tall enough to sit against the vehicle seat back with his or her knees bent at the edge of the vehicle seat without slouching and stay in this position comfortably throughout the trip?
Does the shoulder belt lie across the middle of the chest and shoulder, not against the neck or face?
Is the lap belt low and snug across the upper thighs, not the abdomen?