New Hampshire law states that children under the age of 18 must be properly restrained and that children under 6 years old, or under 55 inches tall, must be properly seated in the appropriate child restraint system. However, once your child has outgrown the infant rear-facing seat and has been in a forward-facing harnessed seat for a while, you may begin considering moving her to a booster seat that uses only a regular seat belt. In New Hampshire, there are several regulations your child must meet to ride in a booster.
In New Hampshire, only children ages 5 and under are required to ride in a child safety seat, such as a harnessed seat or a booster. However, many children ages 6 and up still meet the other requirements for riding in a booster seat. If your child is over the age of 5 but should still ride in a booster according to height and weight or isn't big enough to sit correctly in a seat belt, consider keeping him in a booster for a longer time period.
Children must be at least 40 pounds to ride in a belt-positioning booster seat in New Hampshire. Check the manufacturer's requirements for specific weight limits, but many boosters work until children are 100 pounds or more. Although the minimum weight in New Hampshire is 40 pounds, the American Academy of Pediatrics now recommends that children stay in a forward-facing harnessed seat until they outgrow that seat according to height or weight, which is often closer to 65 to 80 pounds depending on the seat.
Children in New Hampshire who use a booster seat rely on the car's standard safety belt to protect them in a crash. Children riding in a booster must always use both a lap and shoulder belt, not a lap belt alone. If your car does not have enough shoulder belts in the back seat, contact the manufacturer to see if you can add one, but do not allow your child to ride with a booster seat and lap belt alone.
Seat Belt Test
If you feel your child no longer needs a booster or he's reached New Hampshire's minimum age requirement but he is still under the height or weight limit of the seat, consider keeping him in the booster if he does not pass all of the seat belt test requirements. To use a regular seat belt, a child's knees should bend comfortably over the edge of the seat, the seat belt should cross between the child's neck and shoulder, the lap belt should fit over the hips and the child should be able to stay correctly seated for the entire ride, even on long trips. If he does not meet these requirements, he may be better of staying in a booster seat until he does.