May 15 (HealthDay News) -- About two-thirds of children's booster car seats may be improperly installed or are being misused, a new analysis shows.
Researchers evaluated 564 children using booster seats at fast-food restaurants and discount stores in Indiana. Common mistakes observed in the study included shoulder belts being too slack or misplacement of the shoulder restraint under the child's arm, behind their back or over an arm rest.
"Our findings clearly show that booster seats are not protecting children because of user error. Parents need to know how to safely place a child in a booster, supervise the buckling up of children who put themselves in the seat, and double check that the shoulder and lap belts restraining the children remain properly positioned during the drive," study first author Dr. Joseph O'Neil, an associate professor of pediatrics at the Indiana University School of Medicine, said in a news release issued by the university.
The findings appear in the May issue of Accident Analysis and Prevention.
Most states now require the use of booster seats for children riding in cars and trucks once they outgrow a standard five-point harness car seat. The purpose of the booster seat is to raise the height of a seated child so that an adult-sized shoulder restraint fits properly.
O'Neil said, ideally, older children should use a booster seat until they reach a height where their knees extend over the seat at a 90-degree angle and their feet touch the floor while sitting firmly against the car or truck seat. Because of the danger of front-end collision and the powerful force of front airbags, O'Neil also pointed out that all children younger than 13 should use only the back seat.
SOURCE: Indiana University School of Medicine, news release, May 11, 2009