In California, a child needs a booster seat once they outgrow the harness on their forward-facing car seat, and they must stay in it until they turn eight years old or reach 4 feet 9 inches tall, whichever comes first. That is the legal minimum. Whether the booster actually comes out at eight is a different question, and it depends on how the seat belt fits.1California Highway Patrol. Child Safety Seats
When a Child Moves Into a Booster
There is no specific age in California law that triggers the switch to a booster. The move happens when a child outgrows the height or weight limits printed by the manufacturer on their forward-facing harnessed car seat. At that point, the child transitions to a belt-positioning booster, which raises them up so the vehicle’s lap and shoulder belts cross the strongest parts of the body rather than the stomach or neck.
Until that transition, California requires every child under eight to be secured in an appropriate child passenger restraint system. The booster is what fills the gap between the harnessed car seat and the adult seat belt.
When a Child Can Stop Using a Booster
Legally, a child can stop using a booster once they either turn eight or reach 4 feet 9 inches tall.1California Highway Patrol. Child Safety Seats Hitting one of those marks satisfies state law. It does not automatically mean the seat belt fits safely.
Seat belts are engineered around adult bodies. A belt that sits in the wrong place on a small child can cause serious internal injuries in a crash. Before retiring the booster, run the five-step fit test:
- The child sits all the way back against the vehicle seat.
- Their knees bend comfortably at the edge of the seat cushion.
- The lap belt sits low across the upper thighs and hips, not the stomach.
- The shoulder belt crosses the center of the chest and shoulder, not the neck or face.
- The child can hold that position for the entire ride without slouching or shifting.
If any answer is no, the child needs to keep using the booster regardless of age or height.2Los Angeles County Department of Public Health. Child Passenger Safety An eight-year-old who is small for their age may legally qualify to use just a seat belt but still be safer boosted for another year or two. NHTSA actually recommends booster use through age 12 or until a child passes a proper fit test.3NHTSA. Car Seat Recommendations for Children California’s age-eight rule is the floor, not the ceiling.
Front Seat or Back Seat
Children under eight must ride in the back seat.1California Highway Patrol. Child Safety Seats Frontal airbags deploy with enough force to seriously injure a small passenger, and the back seat puts distance between the child and that risk. California allows a child under eight to ride up front only in narrow situations:
- The vehicle has no rear seat.
- The rear seats are side-facing jump seats that can’t safely hold a car seat.
- The child restraint system cannot be properly installed in the back seat.
- Every rear seat position is already occupied by a child seven or younger.
- A physician has documented a medical reason the child cannot ride in the rear.
When one of these applies, the child still needs the correct restraint for their age and size, and the front seat should be pushed as far back from the dashboard as possible if the passenger airbag cannot be turned off. Once a child is eight or older and passes the fit test, they can ride in the front, though NHTSA recommends keeping children in the back seat through age 12.3NHTSA. Car Seat Recommendations for Children
Boosters in Taxis, Uber, and Lyft
California does not exempt taxis, rideshares, or any other for-hire vehicles from its child restraint laws. Every rule above applies whether you’re in your own car or in an Uber. The driver isn’t required to supply a car seat, so you need to bring your own or book through a car-seat-equipped option where the app offers one. Many states offer a for-hire exemption. California doesn’t.
Fines for Skipping the Booster
Failing to properly restrain a child is a traffic infraction. The base fine is $100 for a first offense and $250 for each subsequent offense. Those base numbers are misleading. Once California’s mandatory penalty assessments, surcharges, and court fees are added, a first offense can run $500 or more, and a second can exceed $1,000. A conviction also adds one point to the driver’s DMV record, which can push up insurance premiums.1California Highway Patrol. Child Safety Seats
A court may reduce or waive the fine if the driver completes a child passenger safety education class, provided one is offered within 50 miles of home.4California Department of Public Health. VOSP E-Newsletter Spring 2024 Fines apply per child, so two improperly restrained kids means two tickets. When the parent is in the car, the parent gets cited; when not, the driver does.
Choosing and Maintaining the Booster
Booster seats expire. Most have a date stamped on the shell, typically about six years from manufacture. Plastic and foam degrade from heat, cold, and everyday use, and an old seat may not perform as designed in a crash. Check the label and replace the seat before that date.
Register the seat with the manufacturer so you’ll get recall notices. NHTSA’s free SaferCar app also sends recall alerts.5National Highway Traffic Safety Administration. Car Seats and Booster Seats After a crash, the seat may need replacing. NHTSA says a seat does not need replacing after a minor crash where the vehicle was drivable, no one was injured, the nearest door was undamaged, no airbags deployed, and the seat shows no visible damage. If any of those conditions isn’t met, replace the seat.6National Highway Traffic Safety Administration. Car Seat Use After a Crash
Buying a Used Booster
Before accepting a secondhand seat, verify it has never been in a moderate or severe crash, is not expired, has not been recalled, and still has all its parts and the original manual. Missing labels or an unclear manufacture date are reasons to pass.7National Highway Traffic Safety Administration. Used Car Seat Safety Checklist
Low-Cost Car Seat Programs
California directs local health departments to keep listings of low-cost car seat purchase, loaner, and education programs in each county. The California Office of Traffic Safety hosts a searchable directory by county.8California Office of Traffic Safety. Who’s Got Car Seats Some programs provide seats free to qualifying families and include installation help from a certified technician.