Car Seat Don'ts
DON'T put an infant in a forward-facing car seat. A baby should ride in a rear-facing car seat until he's at least 1 year old and weighs 20 pounds. If your baby is less than 1 year but weighs more than 20 pounds, put him in a convertible rear-facing car seat.
DON'T forget to tighten the safety-belt attachments when installing your seat. The seat is too loose if you can wiggle it more than an inch from side to side.
DON'T put your car seat or booster in the front seat. Children must be at least 13 before they can ride in front.
DON'T forget to check that the tethers are attached correctly if your car uses the LATCH system. For a rear-facing seat, you need to use only the lower attachments; for a forward-facing seat, also use the top tether. Be sure to tighten all straps.
DON'T ignore height guidelines for your rear-facing infant seat. A baby's head should be at least an inch below the top of the car seat's shell. If it isn't, it's time to switch to a rear-facing convertible seat.
DON'T leave the harness straps loose. The straps are tight enough when you can't pinch any harness fabric between your fingers and you can fit only one finger underneath.
Sources: Flaura K. Winston, M.D., Ph.D., scientific director of pediatric trauma at the Children’s Hospital of Philadelphia; National Highway Traffic Safety Administration; American Academy of Pediatrics; Stephanie Tombrello, executive director of SafetyBeltSafe U.S.A.; and Partners for Child Passenger Safety.