IIHS's safest booster seats

(CBS) -- A crash test video shows how unrestrained children can become projectiles, even in a low-speed collision.

Kids wearing only seatbelts can also be seriously hurt if the belt doesn't fit properly.

"We know that kids that are age 4 to 8 are 45% less likely to be injured in a child booster seat than in a seat belt alone," IIHS Senior Research Engineer Jessica Jermakian says.

13 out of 16 new booster seat models sold in 2017 have earned the Insurance Institute for Highway Safety's highest rating.

"A "best bet" booster will provide good belt fit on a typical child 4 to 8 years old in almost any vehicle," Jermakian says.

The Cosco Finale and the backless Chicco GoFit, along with the Maxi-Cosi RodiFix and Diono Monterey XT booster seats are among those awarded the top rating.

"What we're looking for is for the shoulder belt to be positioned at the center of the shoulder so it's not falling off the shoulder or riding up the center of the neck. On the lap belt, we're looking for it to be low across the hips," says Jermakian.

Three other seats -- the Harmony Folding Travel booster, the Kiddy Cruiser 3 and the Ride Safer Delighter were rated "check fit".

"A check fit booster means the booster seat will provide good belt fit for some kids in some vehicles," Jermakian says.

The 2017 best bet booster seats range in price from about 40 to 250 dollars.

The IIHS recommends children use booster seats until safety belts fit properly, regardless of their age.

"What we tell parents is that safety is not negotiable," says Jermakian.

The IIHS says that means some kids will be safer in booster seats until they're as old as 12.