New baby- and booster-seat guidelines may hassle parents and embarrass tweens, but pediatricians say safety gains override inconvenience and pride.

“The car is one of the most dangerous places for your child,” says highly rated Dr. Wendy Sue Swanson, on staff at Seattle Children’s Hospital. “This is a no-brainer.”

The American Academy of Pediatrics and the National Highway Traffic Safety Administration recently revised child-restraint recommendations, calling for children to:

• Ride rear-facing until age 2, or until they reach the maximum height and weight for their seat (old guidelines called for children to face front until age 1 or 20 pounds). Children age 2 or older, or those younger than 2 who’ve reached their rear-facing seat’s weight or height limit, should use a forward-facing seat with a harness for as long as the owner’s manual allows.
• Use a booster seat, which ensures proper seat-belt placement across the lower and upper body, until they are 4 feet 9 inches tall and between 8 and 12 years old.
• Ride in the back seat of a vehicle, considered the safest part of the car, until they’re 13.

Swanson and other pediatricians, including Dr. Joseph O’Neil of Indianapolis’ highly rated Riley Hospital for Children, say they advised parents to follow these guidelines even before the AAP and NHTSA announced the revisions.

“They’re based on solid data that matches what happens in a crash,” O’Neil says. “There are actually three crashes. The first is when you hit something. The second is when you hit the inside of the car and the third is when your organs hit the inside of you.

“Car seats and seat belts keep children in the vehicle, hold their bodies at the strongest parts and spread the forces of the crash so there’s not too much stress on any one part,” he says.

Infants in rear-facing seats are five times safer than those facing forward, says Sharon Evans, injury prevention coordinator at highly rated Cook Children’s Medical Center in Fort Worth, Texas. “Babies’ heads are the biggest, heaviest part of their bodies. Rear-facing, the head and neck are cradled, versus when you turn them around and the head pitches forward in a crash,” she says.

Evans and other experts say parents mistakenly think babies have outgrown rear-facing seats when their legs extend over the edge. However, bent legs pose no problem for babies, whose joints flex easily. “If the child’s head is an inch shorter than the back of the seat, they are probably within the guidelines,” O’Neil says, adding that parents should check seat instructions.

Pediatricians acknowledge that parents of babies embrace the revised recommendations more willingly than parents of older children.

“I’m not hearing as many objections to the rear-facing infant-seat guideline as I am to the belt-positioning booster seat,” says highly rated Dr. James R. Cumming of Carmel, Ind. “Parents say, ‘My child won’t use a seat because other kids make fun of them.’”

He and Evans say parents need to value safety above all. “I know seats are a hassle,” Evans says. “But I work in the trauma area, where there are no do-overs.”

The new advice surpasses requirements of all state laws, says Russ Rader, spokesman for the Insurance Institute for Highway Safety. He says the lack of a federal child-restraint law creates "a hodge-podge of laws that don't match the latest safety recommendations."

O'Neil says state laws set minimum standards. He urges parents to follow the new guidelines. "Just because the law of the land says a child can sit a certain way doesn't mean the law of physics agrees," he says.

Read the detailed guidelines at healthychildren.org.