(ARLINGTON, Va.) -- Parents of young children now have a better selection than ever of car booster seats that offer good protection.
These seats are usually used with children age 4 to 8, and they're designed to raise up those smaller bodies so they fit properly into the car seatbelts.
The Insurance Institute for Highway Safety examined more than 80 models, and found that 31 of them would correctly position a seatbelt in any type of vehicle: an SUV, minivan or car. That's up from 21 top-rated seats last year, and nine the year before.
"We're encouraged that there are more top-rated seats available for parents," Anne McCartt, senior vice president of the Insurance Institute, told ABC News. "We think a lot of that is that manufacturers are paying attention to our ratings and modifying their seats or introducing new seats that do a good job."
The seats should work to position lap belts across the upper thigh, not across the child's abdomen. And shoulder straps should fit across the middle of the shoulder, not over the arm or neck. Studies have shown booster seats can reduce the likelihood of injuries in a crash by 45 percent.
The institute's ratings are not based on crash tests but on measurements.
"We will take a 6-year-old dummy," says McCartt, "and we specially outfit it and we place it in a booster, installing it according to the manufacturer guidelines."
The institute then fastens four different types of lap-shoulder belts, representing what's found in today's vehicles, to see how well they fit.
The group's 31 Best Bets include booster seats with backs, and booster seats with just bases. They even include a new inflatable seat called the BubbleBum, designed for families on the go. One company, Harmony Juvenile Products, located in Canada, had all five of the seats it manufactures on the top-rated list. Seats by Britax, Evenflo, Graco and SafetyFirst also made the list.
Not all seats made the grade. Six of them did not perform well, and the institute says it can't recommend them. Those are four models made by Evenflo -- the Case, Express, Generations 65 and Sightseer -- and two SafetyFirst seats -- the All-In-One and the Alpha Omega Elite.
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