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Fact check: What is the age requirement for a booster seat in California?
Executive Summary
California’s baseline requirement still requires children to use booster seats until they turn 8 years old or reach 4 feet 9 inches in height, and that baseline remains the operative rule for immediate booster-seat eligibility [1] [2]. A 2025 package of changes signed into law adds a new compliance layer beginning in 2027: children aged 8 through 16 must meet a five-step seat-belt fit test to be considered properly restrained, with potential fines for drivers who cannot affirmatively answer the test questions about their passenger [2] [3].
1. Why the rule looks the same but may feel very different: law retained the familiar 8-or-4’9” threshold
California’s longstanding statutory threshold — children must use a car seat or booster until they are 8 years old or at least 4 feet 9 inches tall — remains the immediate legal standard and was established in prior statewide guidance and statutes dating back to the 2017 law [1]. Media coverage of the 2025 legislative changes emphasizes continuity: the new measure does not lower that age/height cutoff and therefore parents will still rely on the familiar metric when deciding whether a child “graduates” from a booster now [2]. The significance lies not in changing the numerical cutoff but in layering a fit-based evaluation on top of that rule starting in 2027, which reframes how compliance and enforcement will be judged. This preserves the previous rule while signaling a shift toward individualized assessment of restraint fit.
2. The five-step test: a new gatekeeper for seat-belt adequacy starting in 2027
The 2025 law institutes a five-step test that must be affirmatively passed for a child between 8 and 16 to be legally considered properly restrained by a vehicle seat belt starting in 2027 [2] [3]. Reporting describes the test as focused on concrete fit indicators—lap belt placement, shoulder belt placement, posture, and seating position—and requires drivers to be able to answer questions about the child’s positioning; failure to do so can trigger penalties [3]. The new rule shifts enforcement from a simple age/height threshold to a behavioral and fit-oriented standard, aiming to capture shorter adolescents who still need booster-style belt positioning even after turning eight. Advocates frame this as safety-driven; opponents argue it introduces enforcement complexity and ambiguity in real-world traffic stops [3] [4].
3. Penalties and enforcement: what happens if the five-step test isn’t met
Under the enacted 2025 changes, if a driver cannot affirmatively answer the five-step questions about a child passenger aged 8–16 in 2027 and beyond, the driver may face monetary penalties—reporting cites fines in the ballpark of $490 applied as a result of noncompliance [3]. Media summaries emphasize that enforcement will rely on the driver’s ability to verify the child’s fit rather than on an officer measuring height at the roadside, creating room for discretion and variability in application [3]. The law’s drafters paired fines with an educational approach in some descriptions, but reporting notes that the combination of penalties and a new subjective test raises concerns among families and civil-liberties advocates about inconsistent enforcement and potential for disputes during traffic stops [4] [3].
4. What the legislative process reveals: amendments, compromises, and political framing
The measure evolved in the legislative process: an earlier draft would have gone further by restricting front-seat riding for teens up to age 16 who failed the fit test, but that provision was watered down during negotiations to preserve customary front-seat privileges and to reduce controversy [4]. Proponents argued the original stricter language would have maximized safety; opponents framed it as overreach that interfered with family autonomy and teen norms. The final law represents a compromise that keeps the traditional age/height baseline while creating a post-2026 fit-test regime—an outcome reflecting both child-safety advocacy and political concerns about enforcement burden and parental discretion [5] [4].
5. Bottom line for parents: follow current rule now, prepare for fit checks soon
For practical purposes today, parents should continue to follow the established legal standard by keeping children in a booster until at least age 8 or 4’9” tall [1]. Starting in 2027, families should be prepared to evaluate older children against the state’s five-step fit test and to document or demonstrate proper belt fit to avoid fines and to maximize safety; the law’s effect is to encourage keeping shorter children in boosters longer even if they have reached age eight [2]. The law’s compromise text and phased enforcement reflect competing priorities—child safety advocates pushing for fit-based rules and critics warning about enforcement complexity—so expect continued discussion and public education from state agencies as the 2027 implementation date approaches [5] [3].