Ratings from the Insurance Institute for Highway Safety take the guesswork out of selecting boosters most likely to provide good lap and shoulder belt fit in a range of vehicles. Fit is important because safety belts are designed with adults in mind, not kids.
Proper belt fit
Boosters elevate children so that safety belts designed for adults will fit better. The lap belt should fit flat across a child’s upper thighs, not across the soft abdomen, which is more likely to be injured in a crash than bony structures like the pelvis.
The shoulder belt should cross snugly over the middle of a child’s shoulder. Then it’s in position to provide effective protection in a crash. Plus it’s comfortable to use, so a child won’t be as likely to move it behind the back or under an arm.
Test protocol
The Institute assessed the boosters at its Vehicle Research Center using a specially outfitted crash test dummy representing an average-size 6-year-old child. Engineers measured how 3-point lap and shoulder belts fit the dummy in each of the tested boosters under 4 conditions spanning the range of safety belt configurations in vehicle models. An overall rating for each booster is then assigned based on the range of scores for the lap and shoulder belt measurements.