Minnesota Booster Seat Requirements: Age, Height, and Exceptions

Minnesota booster seat requirements say a child must ride in a booster seat once they are at least four years old and have outgrown their forward-facing harness seat, and they must stay in the booster until they are at least nine years old or have outgrown the booster’s manufacturer height or weight limit, whichever comes first.¹ The rule took effect August 1, 2024, when the state raised the previous age threshold under Statutes § 169.685. The driver is legally responsible for every passenger under 18 being properly restrained.

When a Child Must Start Using a Booster

A child moves into a booster seat once two conditions are both met: they are at least four years old, and they have outgrown the height or weight limit of their forward-facing seat with an internal harness.¹ Age alone isn’t the trigger. If your four-year-old still fits within the harness seat’s limits, they stay in the harness.

The booster itself is used with the vehicle’s lap-and-shoulder belt, not an internal harness. The belt does the restraining; the booster’s job is to raise the child so the belt lies in the right place on the body.

When a Child Can Move Out of the Booster

A child can transition from a booster to the seat belt alone when they are at least nine years old, or when they have outgrown the booster’s manufacturer height or weight limit. Minnesota does not set a single statutory height like 4 feet 9 inches. The transition is tied to the limits printed on your specific booster’s label or listed in its manual.¹

Reaching age nine doesn’t automatically make the seat belt safe. The statute spells out what a correct fit looks like, and the driver can still be cited if the belt doesn’t sit properly on the child. The belt fits correctly when all of the following are true:¹

The child sits all the way back against the vehicle seat.
The child’s knees bend over the edge of the seat.
The lap belt sits snugly across the upper thighs and lower hips, not the abdomen.
The shoulder belt crosses the center of the chest, not the neck or face.

If the belt rides up onto the stomach or the shoulder strap cuts across the neck, keep the child in the booster. Tucking the shoulder belt behind the back or under the arm is both unsafe and illegal; the belt has to stay in the correct position across the chest for the entire trip.¹

Back Seat Rule for Children Under 13

A child in a booster in Minnesota must ride in the back seat whenever a rear seating position is available. The statute applies this rule to all children under 13, regardless of whether they’re still in a booster or have moved to a seat belt.¹

If you’re transporting more children under 13 than you have seat belts for, any unrestrained child must be placed in a rear seat.¹ The safer approach is to make sure every child in the vehicle has a properly sized restraint before you start driving.

Exceptions

Minnesota carves out a handful of situations where the booster requirement doesn’t apply. These cover specific vehicle types and medical circumstances, not everyday driving.

A child who cannot safely use a restraint because of a medical condition, body size, or physical disability is exempt if a licensed physician has made that determination. Keep the documentation in the vehicle.¹
Taxis, airport limousines, and buses are exempt. This does not extend to rental, leased, or borrowed vehicles. If you rent a car, you need a booster.¹
School buses with a gross vehicle weight rating over 10,000 pounds are exempt.¹
Emergency medical personnel transporting a child on duty are exempt when a restraint isn’t available or the child’s medical needs make one impractical. Peace officers are similarly exempt when no car seat is available, though they must use a seat belt as a substitute.¹
Vehicles manufactured before January 1, 1965, are outside the restraint rules because they weren’t required to have factory-installed seat belts.

Penalties and How to Reduce the Fine

A violation is a petty misdemeanor carrying a fine of up to $50.¹ Court costs and surcharges can add to that if the citation goes unresolved.

The statute gives you a way to reduce or waive the fine. If you show proof within 14 days that you purchased or obtained a compliant child restraint system for your use, the court can dismiss or lower the penalty.¹ Officers may also hand you information about free or low-cost car seats at the time of the stop.

1
Minnesota Office of the Revisor of Statutes. Minnesota Code 169.685 – Seat Belt Passenger Restraint System for Children