Seat type	Child size*	Benefits	Cautions
Car bed	Premature infants until they are able to maintain their airway while sitting semi-upright	Only seat that allows supine transportation	A child outgrows this seat rather quickly
Infant seats	Less than 20 to 22 lb (9 to 10 kg)s	Lightweight, usually less expensive, these seats can be used as infant carriers outside of the car	Must always face the rear of the car; not designed for bigger infants; need to be reclined to 45 degrees to maintain the airway
Convertible seats	Rear facing: to one year of age, weight limits 20 to 30 lb (9 to 13.5 kg), depending on the manufacturer Forward facing: older than one year, weight limits 20 to 40 lb (9 to 19 kg)	Can be used for a larger age/weight range; some seats are now designed to convert to booster seats	Seats can be bulky; when rear-facing they need to be reclined to 45 degrees; when forward-facing, the seat should be upright; harness straps need to be at or below the child's shoulders when rear-facing; harness straps need to be above the reinforced position or above the shoulder when forward-facing
Forward-facing seats	Older than one year, 20 to 40 lb	Designed for children older than one year	Not for children younger than one year
High-back boosters with and without harness	Older than one year With harness: 20 to 40 lb Without harness: 40 to 80 lb (18 to 36 kg)	Can be used for a larger age/weight range; removable harness makes this seat useable past 40 lb	Not for children younger than one year; the weight and height limits of the seat and the harness should be checked to ensure that the child is the appropriate size for the seat or harness
High-back belt-positioning boosters	40 to 80 lb	Lightweight, usually less expensive; designed for older children, so the child does not feel like a “baby”	Only for use by older children who have outgrown the convertible or harnessed seats; ensure the seat belt placement is correct (over the midshoulder and midchest, and tight across the thighs) when using a booster