California Booster Seat Law 2027: Car Seat Rules by Age, Height and the New 5-Step Test

Last verified October 24, 2026 against current California law

The California booster seat law is changing on January 1, 2027, and that change has set off a wave of confusing headlines. Some posts claim every child up to 16 now needs a booster seat. Others claim adults will need one too. Neither is what the law says. Below are the car seat laws in California today, what changes in 2027, the fines, and the exceptions.

The rules live in a short run of Vehicle Code sections: § 27360 for children under 8, § 27360.5 for children 8 to 15, § 27363 for exceptions, and § 27360.6 for fines.

California car seat law at a glance

Item	What California law says
Legal status	Car seats or boosters are mandatory for most children under 8; a car seat, booster or properly fitting seat belt is mandatory from 8 to 15
Age limits	Rear-facing until age 2 (unless 40 pounds or 40 inches); child restraint in the back seat until age 8 (unless 4 feet 9 inches); restraint or seat belt until 16
Limits	Under 8 must ride in the back seat, with six listed exceptions; no rear-facing seat in front of an active airbag
Penalty range	Infraction; $100 base fine for a first offense, $250 for a second, plus one point on the driving record
Governing law	Vehicle Code §§ 27315, 27360, 27360.5, 27360.6, 27363, 12810(h)
Last changed	AB 435 (Chapter 434, Statutes of 2025), signed October 7, 2025, operative January 1, 2027

What are the car seat laws in California by age and height?

California car seat laws set three stages: rear-facing until 2, a car seat or booster in the back seat until 8, and a car seat, booster or seat belt until 16.

Under age 2: rear-facing

A child under 2 must ride in a rear-facing car seat under § 27360(b). The only way out before the second birthday is size: a child who weighs 40 pounds or more, or who is 40 inches or taller, may face forward.

The same subdivision says the child must be secured within the height and weight limits set by the seat’s manufacturer. If your infant seat tops out at 32 inches, the law expects you to move to a seat that fits.

Under age 8: car seat or booster, in the back

A child under 8 must be secured in a child passenger restraint system that meets federal safety standards, and must ride in a rear seat, under § 27360(a). A “child passenger restraint system” covers both forward-facing harness seats and belt-positioning boosters.

There is one size exception. A child under 8 who is at least 4 feet 9 inches tall may use the vehicle’s seat belt instead of a booster under § 27363(d). From January 1, 2027, that child must also pass the five-step test described below.

Ages 8 to 15: car seat, booster or seat belt

Children who are 8 or older but under 16 must be secured in a federally approved child restraint or properly restrained by a safety belt under § 27360.5. Unlike the under-8 rule, this section does not require the back seat.

This is the stage AB 435 changes. Today, a child of 8 or older meets the law with a seat belt alone. From 2027, the belt has to fit the child under a five-part test, or the child stays in a booster.

Child	Required in California	Seat position	Law
Under 2, under 40 lbs and under 40 in.	Rear-facing car seat	Back seat	§ 27360(a), (b)
Under 2, 40 lbs or 40 in. or more	Car seat (may face forward)	Back seat	§ 27360(a), (b)
Age 2 to 7, under 4 ft 9 in.	Car seat or booster	Back seat	§ 27360(a)
Under 8, 4 ft 9 in. or taller	Seat belt allowed (must pass 5-step test from 2027)	Back seat advised by CHP	§§ 27360(a), 27363(d)
Age 8 to 15	Car seat, booster or seat belt (belt must pass 5-step test from 2027)	Any seat	§ 27360.5
16 and older	Seat belt	Any seat	§ 27315

What is the new booster seat law in California?

The new booster seat law in California is AB 435, which Governor Newsom signed on October 7, 2025, as Chapter 434 of the Statutes of 2025, and it takes effect January 1, 2027.

AB 435 does not raise the booster seat age. It does not touch § 27360 at all. What it changes is the meaning of the phrase “properly restrained by a safety belt” across §§ 27315, 27318, 27360.5 and 27363.

Under current law, a belt counts as proper if the lap part crosses the hips or upper thighs and the shoulder part crosses the chest. Starting in 2027, a child 8 to 15 riding with only a seat belt is properly restrained only if all five of these are true:

• The child sits all the way back against the vehicle seat.
• The child’s knees bend over the edge of the seat.
• The shoulder belt snugly crosses the center of the chest and shoulder, not the neck.
• The lap belt sits as low as possible and touches the thighs.
• The child can stay seated like this for the whole trip.

If your child fails any one step, the seat belt alone does not satisfy § 27360.5 from 2027, and the child needs a booster or other child restraint.

What AB 435 originally proposed

The bill as first written in 2025 went much further. The version heard in the Assembly Transportation Committee would have required a child restraint in the back seat for all children under 10, required one for children 10 to 12 unless they passed the five-step test, let 13- to 15-year-olds ride up front only if they passed the test, and removed the 4 feet 9 inch height exemption. Those parts were cut before passage.

Is the California booster seat law real, and does it apply to adults?

The 2027 change is real, but there is no California law requiring adults or all teens to sit in a booster seat.

Here is where the “booster seat law for adults” rumor comes from. AB 435 rewrote the definition in the general seat belt law, § 27315(c)(2), so from 2027 the same five-step wording applies to drivers and passengers 16 and older. But § 27315 only requires people 16 and over to wear a seat belt. It says nothing about boosters, and adults are not covered by the child restraint sections.

The fine for an adult seat belt violation also stays where it was: a base fine of up to $20 for a first offense and up to $50 for each later offense under § 27315(h).

When can a child sit in the front seat in California?

A child under 8 may ride in the front seat only in a properly secured car seat or booster, and only if one of six exceptions in § 27363(e) applies:

• The vehicle has no rear seat, such as a single-cab pickup.
• The rear seats are side-facing jump seats.
• The rear seats are rear-facing seats.
• The child restraint cannot be installed properly in the rear seat.
• Every rear seat is already taken by children 7 or younger.
• Medical reasons require the child to ride up front. A court may ask for proof.

Even under those exceptions, § 27363(f) bans a rear-facing seat in a front seat that has an active frontal passenger airbag. Once a child turns 8, California law sets no minimum age for the front seat, though vehicle makers and safety groups recommend the back seat through age 12.

Other exceptions in California car seat law

California allows a few more exceptions, and each one is narrow. Most are in § 27363; the parent-on-board rule is in §§ 27360(c) and 27360.5(b).

• Driver with a parent on board. The child restraint rules in §§ 27360 and 27360.5 do not apply to a driver if the child’s parent or legal guardian is also in the car and is not driving, under §§ 27360(c) and 27360.5(b). In that case the parent is the one responsible.
• Medical or size exemption. A court may exempt a child whose physical condition, medical condition or size makes a restraint impractical, under § 27363(a).
• Emergencies. In a life-threatening emergency, or in an authorized emergency vehicle with no restraint available, a child may ride with a seat belt instead, under § 27363(b).
• Lap belt only. A child over 40 pounds may ride in the back with just a lap belt if that seat has no lap and shoulder belt, under § 27363(c).

Penalties for breaking California car seat laws

A car seat or booster violation is an infraction, not a crime, with fines set by Vehicle Code § 27360.6 and one point on your driving record under § 12810(h).

Violation	Classification	Base fine	Other consequences	Law
Child under 16 not properly restrained, first offense	Infraction	$100	One DMV point; court may reduce or waive fine for hardship if you complete a car seat education program	§§ 27360, 27360.5, 27360.6, 12810(h)
Second or later offense	Infraction	$250	One DMV point per conviction; same hardship option	§§ 27360.6, 12810(h)
Driver or passenger 16+ without a seat belt	Infraction	Up to $20 first, up to $50 after	Court may allow traffic school for a first offense	§ 27315(h)
Misdemeanor, wobbler or felony	None in the car seat statutes	Not applicable	A crash that injures an unrestrained child can lead to separate charges under other laws	Not applicable

The base fine is not what you pay. State and county penalty assessments are added to every traffic fine in California, so the total on the courtesy notice is several times higher. If you show economic hardship, § 27360.6 lets the court cut or waive the fine and send you to a community class on installing car seats instead. That class requirement is dropped if no program exists within 50 miles of your home.

Real California scenarios

• Your 9-year-old in Sacramento is 4 feet 5 inches tall. Today she can legally ride with just the seat belt. In February 2027, if her knees do not bend over the seat edge or the shoulder belt rides on her neck, she fails the test and needs a booster.
• Your 7-year-old in Los Angeles is already 4 feet 10 inches. He may use the seat belt instead of a booster under § 27363(d). CHP still advises that children under 8 ride in the back seat, and from 2027 the belt must pass the five-step test.
• Grandma drives three grandkids to school in San Jose with their mom in the passenger seat. Because the parent is in the car and not driving, the restraint rules do not apply to Grandma under §§ 27360(c) and 27360.5(b). Responsibility falls on the mom.

Myths vs facts about the new California booster seat law

Myth	Fact
“Every child up to 16 must use a booster starting in 2027.”	Only children 8 to 15 who fail the five-step belt fit test need a booster or other restraint.
“The booster seat age is going up to 10 or 13.”	Those ages were in an early draft of AB 435 and were removed. The under-8 rule in § 27360 is unchanged.
“Adults will need booster seats.”	No section requires an adult booster. Adults must wear a seat belt under § 27315, as before.
“The new law already applies.”	The five-step test is operative January 1, 2027. Until then, the current lap-and-chest definition controls.
“A child seat ticket does not affect your record.”	A conviction under § 27360 or § 27360.5 adds one point under § 12810(h).

Does car seat law differ in Los Angeles, San Francisco, San Diego or San Jose?

No. Child restraint rules come from the state Vehicle Code, and they apply the same way in every California city and county, whether the stop is by the CHP on Highway 101 or by city police in San Diego.

What differs locally is help with installation. California Highway Patrol area offices offer free car seat inspections by appointment, and county health departments run the low-cost seat programs funded by § 27360.6 fines.

How California compares with Nevada, Oregon and Arizona

California’s under-8 rule matches its neighbors closely, but its 2027 five-step test for kids up to 15 is stricter than any of them.

State	Rear-facing	Car seat or booster until	Back-seat rule
California	Under 2 (unless 40 lbs or 40 in.)	Age 8 or 4 ft 9 in.; five-step belt test for ages 8 to 15 from 2027	Under 8, with exceptions
Nevada	Under 2	Under 6 and under 57 in. (released at age 6 or 57 in., whichever comes first)	Under 2 rear-facing must ride in back (limited exceptions)
Oregon	Under 2	Age 8 or 4 ft 9 in.	No general rule
Arizona	No age-based rule	Age 8 or 4 ft 9 in.	No general rule

California’s rules apply to every vehicle on California roads, including visitors with out-of-state plates. If you are driving in from Las Vegas with a 7-year-old in a seat belt, the child needs a booster once you cross the state line, unless the child is at least 4 feet 9 inches tall.

What to do if you get a car seat ticket in California

A car seat citation is handled by the traffic division of the superior court in the county where you were stopped, and your main options are to pay, ask for a hardship reduction, or contest it.

• Check which section was cited: § 27360 (under 8) or § 27360.5 (8 to 15).
• Check whether an exception applied, such as the child’s parent riding as a passenger or the 4 feet 9 inch rule.
• If money is tight, ask the court about the economic hardship option in § 27360.6 and the car seat education class.
• Get the right seat installed before your next drive. A CHP area office can check the fit for free.
• Respond by the date on your courtesy notice so a failure-to-appear charge is not added.

For other rules that affect drivers, see our guide to legal tint in California, browse all California driving and vehicle law guides, and watch California Legal News for laws taking effect each January.

Frequently asked questions

What is the booster seat law in California?

Children under 8 must ride in a car seat or booster in the back seat under Vehicle Code § 27360, unless they are at least 4 feet 9 inches tall under § 27363(d). Children 8 to 15 must use a child restraint or a properly fitting seat belt under § 27360.5. From January 1, 2027, the belt must pass a five-step fit test, or the child stays in a booster.

What is the new booster seat law in California for 2027?

AB 435, signed October 7, 2025, redefines “properly restrained by a safety belt” starting January 1, 2027. A child 8 to 15 must sit all the way back, bend the knees over the seat edge, have the shoulder belt across the chest and shoulder, have the lap belt low on the thighs, and stay that way the whole trip. Failing any step means a booster is needed.

Is there a California booster seat law for adults?

No. AB 435 applies the same five-step wording to the general seat belt law in Vehicle Code § 27315 for people 16 and older, but that section only requires a seat belt. No California law requires an adult to use a booster seat, and the adult seat belt fine stays at up to $20 for a first offense.

How long does a child have to be rear-facing in California?

Until age 2, under Vehicle Code § 27360(b), unless the child already weighs 40 pounds or is 40 inches tall. You must also follow the car seat maker’s height and weight limits, so a child who outgrows an infant seat before 2 needs a larger rear-facing seat, not a forward-facing one.

What age can a child sit in the front seat in California?

Children under 8 must ride in the back unless an exception in Vehicle Code § 27363(e) applies, such as no rear seat or all rear seats taken by younger children. From age 8 there is no legal minimum, though safety experts and vehicle makers recommend the back seat until 13. A rear-facing seat can never go in front of an active airbag.

How much is a car seat ticket in California?

The base fine under Vehicle Code § 27360.6 is $100 for a first offense and $250 for a second or later one. Penalty assessments raise the amount you actually pay, and a conviction adds one point to your driving record. A court can reduce or waive the fine for economic hardship if you complete a car seat education class.

Is the driver or the parent responsible for a child’s car seat?

Both the parent or guardian and the driver can be cited under Vehicle Code §§ 27360 and 27360.5. The exception is when the child’s parent or legal guardian is in the vehicle and not driving. Then the rules do not apply to the driver, and the parent carries the responsibility.

If this affects you: for help choosing or installing a seat, contact your local California Highway Patrol area office or your county health department’s child passenger safety program. For a citation, follow the instructions on the ticket and contact the traffic division of the superior court in your county; a California-licensed traffic attorney can help with a disputed ticket. Read how we check the law, or report an error.