19 of 31 seats earned a top rating, while others still have room for improvement and a couple are not recommended.
The survey looked in particular for seats with a high back, and for proper lap and shoulder belt positioning.
IIHS officials say the lap belt should be low an a child’s upper thighs and the shoulder belt should fit snugly in the center of the shoulder.
Officials want parents to remember that a booster seat should be used until adult seat belts fit, and protect, properly.
You can find the whole report here :http://www.iihs.org/iihs/ratings/child-boosters