New Hampshire Car Seat Laws (2026): Ages & Penalty

New Hampshire requires a rear-facing seat until age 2, then a child restraint system until age 7 or 57 inches, then a seat belt through 17, under RSA 265:107-a. Since 2024, the restraint itself also has to be within the manufacturer's expiration date and used according to its instructions. This page reflects the statute's text as of September 2026.

Jurisdiction scope: This article covers car seat and child-restraint law in the state of New Hampshire only. It does not address any other state. For other states, see the car seat laws hub.

Rear-facing under 2

RSA 265:107-a, I-c prohibits driving with a passenger under 2 years old unless that child is "properly fastened and secured by a rear facing child restraint system."

Under 7 and under 57 inches: the child restraint stage

RSA 265:107-a, I-b separately prohibits driving with a passenger under 7 unless the child is "properly fastened and secured by a child restraint system." This stage ends once the child reaches 57 inches tall or turns 7, whichever comes first, so both conditions (under 7 and under 57 inches) have to hold for the duty to apply.

The 2024 addition: manufacturer instructions and expiration dates

A 2024 amendment, codified at RSA 265:107-a, I-b, added a requirement that's easy to overlook but is a genuine, enforceable part of the law, not just manufacturer advice: every child restraint system has to be used according to its manufacturer's instructions, including the manufacturer's own height and weight limits, proper attachment to the vehicle, correct securement of the child, and the restraint's expiry dates. A family using an expired car seat, one installed contrary to its own instructions, or one used outside the manufacturer's height/weight limits, for a passenger under 7 is out of compliance with New Hampshire law even if the seat itself is the right type for the child's age.

Seat belt through 17

Once a child ages out of the rear-facing and child-restraint stages, New Hampshire's general seat belt requirement in the same statute, RSA 265:107-a, I, covers every passenger under 18: a seat or safety belt, properly adjusted and fastened. A separate paragraph, I-a, imposes a parallel duty directly on a minor driver: a person under 18 who is driving a motor vehicle or autocycle must also be wearing a properly adjusted and fastened seat or safety belt, regardless of whether the vehicle is carrying passengers.

Exemptions

RSA 265:107-a, I is expressly made subject to an exemption paragraph, II, and that paragraph reaches the whole section, including the rear-facing and child restraint duties. A person isn't guilty of a violation if the vehicle they're driving is regularly used to transport passengers for hire (a taxi, livery, or rideshare vehicle), is a school bus weighing more than 10,000 pounds, is a school bus weighing less than 10,000 pounds that was manufactured without safety belts, is carrying a child covered by an individualized education program (IEP) statement that contraindicates the use of restraints, is a vehicle manufactured before 1968, is a motorcycle as defined in RSA 259:63, is an antique motor vehicle, farm tractor, or motorcycle as defined in RSA 259:4, or is being operated in a parade authorized by law or ordinance at no more than 10 miles per hour. A New Hampshire taxi, livery, or rideshare driver, and a school bus driver, fall outside the restraint and seat belt duties under this exemption.

Penalty

A first offense carries a $50 fine. A second or subsequent offense carries a $100 fine. The statute doesn't include a fine-waiver provision for a driver who later shows proof of acquiring a compliant seat. A violation of this section can't be used as evidence of contributory negligence in a civil action.

Leaving a child unattended in a vehicle

New Hampshire doesn't have a criminal statute written specifically for leaving a child alone in a parked car. That's a real gap, but it isn't the same as having no applicable law at all: New Hampshire's general endangering-the-welfare-of-a-child statute, RSA 639:3, makes it a misdemeanor for a person to knowingly endanger the welfare of a child under 18 by purposely violating a duty of care, protection, or support owed to that child. A parent or caregiver who leaves a young child alone in a vehicle under circumstances that amount to a violation of that duty of care could be exposed under this general provision, even without a dedicated vehicle-specific statute. The statute does carry a narrow defense: a person who fails to conform to an otherwise existing duty of care or protection pursuant to the tenets of a recognized religion isn't guilty of an offense under this section.

The 2025 smoking bill that didn't pass

A bill filed in the 2025 session, HB368, would have banned smoking or vaping in a vehicle carrying a passenger under 16. The New Hampshire House voted it "Inexpedient to Legislate" by a 213-157 margin on February 20, 2025, and it did not become law. New Hampshire currently has no statute prohibiting smoking or vaping in a vehicle with a minor passenger; a family shouldn't assume one exists based on this bill having been introduced.

Federal guidance vs. New Hampshire law

The federal standard governing car seats as products, FMVSS 213 (49 CFR 571.213), regulates what a manufacturer may sell, not how a parent must use the seat; New Hampshire's own statute, described above, sets the use requirement, including the 2024 manufacturer-instructions and expiration-date duty. NHTSA and the American Academy of Pediatrics separately recommend keeping a child rear-facing as long as the seat's own height and weight limits allow, which can extend well past New Hampshire's age-2 rear-facing floor. That's safety guidance, not a separate legal floor. A newer federal side-impact standard for car seats themselves, FMVSS 213a/213b, becomes mandatory for manufacturers on December 5, 2026; it changes what a seat must be built to withstand, not what New Hampshire law requires a driver to do.

Related New Hampshire traffic law pages

• New Hampshire DUI laws
• New Hampshire window tint laws
• Car seat laws in every state

Disclaimer: This article provides general legal information about New Hampshire's car seat law as of September 2026. It is not legal advice. Statutes, exemptions, and penalties change; verify the current text of the law before relying on it, and talk to a lawyer licensed in New Hampshire about a specific situation.

Statutes cited reflect their in-force version as of 2026-09-16. Last updated: 2026-09-16.

Frequently Asked Questions

Until what age does a child need a car seat in New Hampshire?

A rear-facing seat is required under age 2. A child restraint system is required under 7, or until reaching 57 inches, whichever comes first. After that, New Hampshire's general seat belt law covers every passenger under 18, under RSA 265:107-a.

Can an expired car seat be used legally in New Hampshire?

No. A 2024 amendment to RSA 265:107-a, I-b requires a child restraint system to be used according to its manufacturer's instructions, including its height and weight limits, proper attachment, correct securement of the child, and its expiration date. This is an enforceable statutory requirement, not just advice.

What is the penalty for a car seat violation in New Hampshire?

A $50 fine for a first offense and a $100 fine for a second or subsequent offense, under RSA 265:107-a. It can't be used as evidence of contributory negligence in a civil case.

Is a New Hampshire taxi or rideshare driver exempt from the car seat law?

Yes. RSA 265:107-a, II exempts a vehicle regularly used to transport passengers for hire, along with a school bus weighing more than 10,000 pounds or a school bus weighing less than 10,000 pounds that was manufactured without safety belts, a vehicle carrying a child covered by an IEP statement contraindicating restraints, a pre-1968 vehicle, a motorcycle, an antique vehicle or farm tractor, and a parade vehicle moving no faster than 10 mph.

Does New Hampshire have a law against smoking with kids in the car?

No. A 2025 bill, HB368, would have banned it for passengers under 16, but it was voted down 213-157 and did not become law. New Hampshire currently has no such statute.

Is it illegal to leave a child alone in a car in New Hampshire?

New Hampshire has no statute written specifically for this. Its general endangering-the-welfare-of-a-child law, RSA 639:3, can still apply to a caregiver who knowingly violates a duty of care owed to a child under 18, which can include leaving a young child alone in dangerous circumstances.