Infant Seats

These are created to hold babies, from newborns to those between 9 and 12 months, in a semi reclined position, facing the rear of the car (toward the trunk). They are secured by the car's adult safety belts, which thread through special slots in the safety seat, and are safest when anchored in the center of the car's backseat. The car seat's handle rotates from an upright position like a basket handle for carrying to laying behind the seat for transport.

Slots in the seat's base are designed to attach to the frame of a shopping cart. Some mid and high priced models offer a base attachment (like a docking station), so the seat may be detached while the secured base stays behind. Stroller/infant seat combination are available, as are car seat/bed combination that ride lengthwise on the car's seat and fold into an upright position.

Infant seats are lighter and less expensive than larger models (they range from $30 to $70), and appear to fit a baby's shape better. A bed model is useful for infants with medical conditions that create breathing problems when the baby is in a sharply reclined seat.

Most infant-only seats have no waist belts. The seat with baby inside is heavy and cumbersome to carry. Baby may exceed the seat's size and weight limits before his neck and back are strong enough to allow him to face forward and then require a convertible seat. Although infant seats may be advertised for home use as rockers and seats, their weight can pose a crushing or suffocation danger if the seat falls. So never place one, with baby inside, on a raised surface, even for a moment.


Convertible Seats

These heavier, convertible seats are usually more expensive - $50 to $210. They have a reclining mechanism so they can ride facing rearward for a baby, or forward for a toddler or young child. Weight specifications vary by model. Weight limits for rear-facing models range from 5 to 10 pounds for newborns, with top limits of 20, 22 or 30 pounds; and forward facing, up to 40 pounds.

Some models have five-point harness systems. Other have U-shaped and T-shaped shields that lower over the baby's head and fasten with a buckle between the legs, or T-shaped shields that resemble upside-down bicycle seats, with the buckling assembly embedded in the narrow end. Most of them even offer tethering option.

When reclined, however, they take up a lot of room in cars with small back seats. Some models, particularly those with front shields, don't fit babies up to two months old very well - seat angles can be too flat, harness slots too high, and the distance between crotch and seat back too wide.


Boosters

Booster seats and high back boosters are designed for kids who have outgrown convertible seats but are still too small for adult safety belt system. More conventional boosters have a rigid base and/or shield that positions adult belts across the thighs and away from the child's neck. High-back boosters resemble convertible seats but are taller. Some only serve as vehicle belt positioners, others have a five-point-harness system that can be removed when a child exceeds 40 pounds.

Boosters raise a child so she can see out and offer better protection than no belts or poorly positioned adult belts. But they won't work if they center of the back seat lacks both adult waist and shoulder belts, and some are difficult to install and adjust. Seats with a high back may block a driver's rear view in small cars, and some are difficult to install and adjust. They are not approved for use on airlines. Prices range from $25 to $150.


Tethering for Safety

Tethering a convertible seat designed for children heavy enough to ride in the forward-facing position adds an extra margin of safety. A tether is an adjustable strap: One end loops over a metal clip or bar installed on the back side of the car seat; the other hooks to an anchor screwed into the metal frame of the rear window self. Even in a properly fastened safety seat, a child may be injured in a head-on crash if the car seat vaults forward, causing his head to collide with the back of the front seat. Crash tests commissioned Consumer Reports showed that tethers improved the protective ability of seats, turning otherwise fair seats into excellent performers. Tethered seats reduced forward head movement of crash-test dummies by about one-fourth, or eight inches.

Increasingly, forward-facing safety seats for children weighing 20 to 40 pounds include a tether as standard equipment. Even models lacking a tether have built-in insets or holes cut for tethering hardware. Some car seat manufacturers, including Evenflo and Century, recommend that a tether be installed to stabilize newer convertibles when standard installation does not work well. (A well installed seat cannot be pushed more than one inch front to back, or one to two inch side to side)

If you decide to add tethering to your child's front-facing seat, first check with the car seat manufacturer to make sure your model can be tethered. Tethering kits-strap, hardware, and directions - are available from baby stores or directly from your car seat's manufacturer for about $15. However, assemblies are not interchangeable, so you must get the right brand to start with.

Ask your car seat manufacturer who is authorized to install the tethering anchor. The corner mechanic may not be up to to the job. Most recent domestic car models have the anchor hole pre-drilled to conform to Canadian car seat standards, but screw sizes are not uniform among car models. Vehicle manufacturers usually offer the tethering bolt and anchor installation for free or at a small price. If you run into blank stares, tell the dealer you want your car equipped with a "Canadian tether".

If you are still having problems, check your car's owner's manual for the original service number.


Seats for special-needs babies

Your hospital or baby's pediatrician may recommend a special car seat for small or low-birth weight babies, such as one without a shield (shields fit smaller babies poorly), or a car bed, which lets a baby completely recline. Before leaving the hospital, your baby may be observed in a car seat to see if the semi reclined position adds to or causes possible breathing problems.

Children with special health problems or medical conditions may need alternative restraint systems. Talk to your pediatrician.