Here is the test.....
When sitting against the back of the vehicle seat...
Does their shoulder belt touch their neck?
Does the lap belt ride up over their belly?
Is it difficult to bend their legs easily over the edge of the seat?
Do they tend to tuck the shoulder belt under their arm, or behind their back or slouch to be comfortable in their seat belt?
If you answer yes to any of these questions, you need to keep your child in their booster seat! Most children will be in their booster seat until they are around 9 years old. Always seat children in the rear of your vehicle, not the front passenger seat.