Massachusetts School Pupil Transport (7D) Certificate Practice Test

Choosing the right restraint depends on a child’s size so the belt fits correctly. A booster seat is used when a child is old enough to sit properly in a seat belt but not tall enough to fit the belt without a booster. In practice, that typically includes children around five to eight years old who weigh about forty to eighty pounds. The booster positions the lap belt low on the thighs and the shoulder belt across the chest, not the neck or stomach, which reduces injury risk in a crash.

The other options don’t align with this belt-fit logic: they place a child in a booster outside the usual weight range, or assume a booster is appropriate for younger ages or different weight ranges than where belt fit is reliable.