Researchers at The Children's Hospital of Philadelphia's Center for Injury Research and Prevention studied nearly 1,000 1- to 8-year-old children involved in crashes and found no evidence of increased injury risk for children across a broad weight range. All of the children included in the study were properly restrained in the correct child safety seat or booster seat（辅助软座垫） for their height and weight. The research also suggests that the current range of child safety seats and booster seats available today sufficiently accommodates（适应，调解） a broad spectrum of children's body sizes, including children with higher weights. The results are published online in the December issue of the journal Pediatrics.

"Given that nearly 32 percent of children in the United States are categorized as overweight or obese, and motor vehicle crashes are the leading cause of death and injury for all children, we wanted to better understand how these two threats to children's health interact," explained lead author Mark Zonfrillo, MD, MSCE, an attending emergency physician at The Children's Hospital of Philadelphia. "This research should reassure parents that their only concern when it comes to car seat safety should be to follow the most recent guidelines set by the American Academy of Pediatrics."

Current American Academy of Pediatrics (AAP) guidelines, revised earlier this year, say that children should remain rear-facing until at least age 2 or until they reach the rear-facing height and weight limit for the car seat. Once forward-facing, children should stay in a five-point harness until they reach the manufacturer's height and weight limit for that seat. They should then move to a belt-positioning booster seat, where they should remain until they are 4'9" tall, usually between ages 8 and 12.

"A good time to re-evaluate child safety seat needs is during your child's routine medical visits. Compare your child's weight and height measurements to the manufacturer's acceptable ranges on the seat's labels or instructions," says Zonfrillo, who is the father of a toddler（学步的小孩） . "There's no 'one-size-fits-all.' If your older child moved to a booster seat at age 5, don't necessarily assume it will be the same for his or her younger siblings."

The authors also note the important role pediatricians（儿科医师） and family physicians play in making sure their patients are well-protected in the car. During each visit where height and weight are evaluated, they should counsel（建议，劝告） parents to check their child's measurements against their child's safety seat. "Physicians should feel comfortable referring patient families with more complex questions to their local child passenger safety technicians, who are trained and certified experts," says Zonfrillo.