Time for a Boost
Once your child outgrows his toddler seat (he's 40 pounds and his head reaches the top of the seat back), he's ready to just use a seat belt, right? Not so fast. Without the extra height and protection from a belt-positioning booster seat, the lap belt may rest across his stomach instead of his hips -- causing serious organ damage in an accident -- and the shoulder belt may be too close to his face or neck. That's why older kids need to ride in a booster until they fit a seat belt properly (usually when they're about 4'9" and weigh 80 to 100 pounds). Your child may not want to stay in a safety seat that long, but don't cave: Riding in a booster seat reduces his risk of injury in a crash by 59 percent compared with using a seat belt alone.
Boosters are available in two styles: highback and backless. If your car's seat back is lower than the middle of your child's ear, go with a high-back booster so she'll have adequate head support. Otherwise, using a backless booster is fine.
1. Giving up the booster too soon.
NHTSA surveys show that only 37 percent of children ages 4 to 7 were riding in a booster seat in 2007. Most states have booster-seat laws (which parents often ignore), but many only cover kids up to age 7.
2. Using the lap belt only.
If you skip the shoulder belt, your child's upper body could jerk forward so violently in a crash that her head may strike her knees or she may suffer severe internal injuries.