Car seat laws in Missouri

Missouri law has no rear-facing requirement. NHTSA and the AAP recommend keeping your child rear-facing as long as possible, until they reach the top height or weight limit allowed by the car seat's manufacturer. A child under age 1 should always ride rear-facing, and most convertible seats allow rear-facing for 2 years or more.

Children at least 4 but under 8 who weigh at least 40 but under 80 pounds and are shorter than 4'9" must be secured in a child passenger restraint system or booster seat. A child who would need a booster may ride with a lap belt only in a back seat that has no lap-and-shoulder belt for the booster. NHTSA and the AAP recommend going further: using a belt-positioning booster seat after your child outgrows the harnessed seat, until the vehicle seat belt fits properly, typically when they reach about 4 feet 9 inches tall and are 8 to 12 years old. The AAP says an adult seat belt fits when: the shoulder belt lies across the middle of the chest and shoulder, not the neck or throat; the lap belt is low and snug across the upper thighs, not the belly; and the child is tall enough to sit against the vehicle seat back with knees bent over the edge of the seat without slouching, and can stay that way for the whole trip. NHTSA uses the same lap-belt and shoulder-belt checks. The 5-step test, which California writes into law from January 1, 2027, asks: 1) Does the child sit all the way back against the seat? 2) Do the knees bend over the edge of the seat? 3) Does the shoulder belt snugly cross the center of the chest and shoulder, not the neck? 4) Is the lap belt as low as possible, touching the thighs? 5) Can the child stay seated like this for the whole trip?

No Missouri law requires children to ride in the back seat. When there are more children than seating positions, children who can't be restrained must ride behind the front seat if the vehicle has a back seat. NHTSA and the AAP recommend keeping all children younger than 13 in the back seat.

Violating the car seat or booster rules is an infraction with a fine of up to $50 plus court costs. The charge is dismissed or withdrawn if the driver shows, before or at the hearing, that they acquired the required seat. For a child who is 80 pounds or more or taller than 4'9", the penalty is the seat belt law's: a fine of up to $10, with no court costs and no points (§ 307.178.6).

NHTSA's locator lists 355 car seat inspection stations in Missouri, in 182 cities and towns. Kansas City and Springfield have the most (10 each). NHTSA flags 4 of them as Spanish-speaking. Certified technicians check seats for free in most cases. Search NHTSA's locator by ZIP code and call the station before you go.