What to Know About Backless Booster Seat Requirements in Colorado

What to Know About Backless Booster Seat Requirements in Colorado

If you're a parent, caregiver, or driver in Colorado, understanding when a child can use a backless booster seat is critical—not only for safety, but because the law sets baseline requirements. Below, we explain how Colorado’s child passenger safety laws treat booster seats (including backless models), what the changes effective in 2025 mean, and how to ensure compliance.

Colorado’s Child Restraint & Booster Seat Framework

Colorado’s law sets out a multi-stage child restraint framework before a child can use a booster (backless or high-back) or transition to a seat belt. These rules are codified in C.R.S. § 42-4-236, and they will also be updated under HB24-1055, which takes effect January 1, 2025.

Key Existing Rules Before 2025

Under current law:

• Children under 8 years old must be restrained in a child restraint system, which includes harnessed car seats or booster seats.
• For children 4 to 8 years old, if they weigh at least 40 pounds, they may use a booster seat (or another restraint) rather than a forward-facing harness seat.
• Children 9 to 18 must be restrained by a safety belt or child restraint system, per the law, so long as the seat belt fits properly.
• Colorado also mandates that children under 9 years of age be seated in the back seat when one is available (if the vehicle has a back seat).

Colorado’s Department of Transportation (CDOT) FAQs further state that booster seats have a minimum requirement: a child must be at least 4 years of age and at least 40 pounds to use them.

If a child is younger than 4, even if they weigh more than 40 lbs, they typically must remain in a harnessed seat until they meet all the criteria for a booster.

Changes Coming in 2025 under HB24-1055

Coming January 1, 2025, HB24-1055 revises Colorado’s child safety laws to reflect updated safety research. Among the changes:

• The age threshold for requiring a restraint system is extended: children under 9 years old must be in an appropriate child restraint system (including booster) rather than the prior “under 8” threshold.
• The rule that a child is 4–8 years old with weight ≥ 40 lbs must be restrained in a booster or child restraint continues, but under the new age bracket (under 9).

Thus, under the new law, a child aged 8 but under 9 may still be required to use a booster or car seat rather than simply a seat belt.

These updates aim to align Colorado law more closely with modern safety guidelines.

What About “Backless” Booster Seats?

A backless booster is a belt-positioning device without a high back or side wings. It raises the child so that the vehicle’s lap and shoulder belts fit correctly, but it doesn’t provide head support.

Here’s what you need to know about using backless boosters in Colorado:

• No distinction in statute: Colorado’s laws do not separately regulate "backless" versus "high-back" boosters. The statutes talk about “child restraint systems” or booster seats generally, relying largely on manufacturer instructions and federal standards.
• Manufacturer guidelines matter: Whether a backless booster is appropriate depends heavily on the booster’s design, the child’s size (height, weight), and how well the vehicle’s seat belt fits. The law requires that child restraints be used in accordance with the manufacturer’s instructions and the vehicle owner’s manual.
• Height limits & age/weight minimums: Even if a child meets the minimum 4 years and 40 pounds threshold, some backless boosters may specify additional minimum height requirements (e.g., 38", 40") or require a certain maturity to sit properly. If the booster fit is poor, it’s safer to stay with a high-back booster longer.
• Seat belt fit test still applies: A booster (backless or otherwise) is generally acceptable only if the child still needs it for proper seat belt fit. Colorado’s law requires that once children reach age 9 (under new rules) or older, they may use a seat belt if it fits properly.
• Crash protection & head support: One drawback of backless boosters is they offer less head and neck support than high-back boosters. In vehicles without headrests or in seats with low backs, a backless booster may not sufficiently protect a child’s head in case of a crash.

So whether a backless booster is legal and safe depends not just on age or weight, but also on whether it positions the child properly and fits the vehicle’s seat and belts.

Steps to Safely Use a Backless Booster Seat

To ensure a backless booster seat is used safely and in compliance:

1. Check age/weight/height minimums: Confirm the child meets minimums (≥ 4 years, ≥ 40 pounds, plus any height minimum given by the booster manufacturer).
2. Read the manufacturer instructions: Confirm the booster is rated for the child’s size and compatible with your vehicle’s seat belt system.
3. Ensure proper belt geometry: The lap belt should lie across the upper thighs (not the abdomen), and the shoulder belt should cross the chest and shoulder (not the neck).
4. Seat position and head support: If the vehicle seat lacks headrests or has a low back, consider using a high-back booster for additional support.
5. Seat the child fully upright: The child’s back should be against the vehicle seat back, and knees should bend over the edge of the seat.
6. Follow the law: Use the backless booster until the child is at least 9 years old (as per the 2025 update), and the seat belt fits properly enough to allow transitioning out of the booster.

Colorado DOT’s FAQ provides a helpful 5-step seat belt checklist to determine if a child is ready to abandon the booster:

• The child sits all the way back against the seat
• Knees bend comfortably at the edge of the seat
• Shoulder belt crosses between neck and arm
• Lap belt lies low across the hips, not the stomach
• The child remains in correct position for the entire ride

If any of those fail, the child should stay in a booster (backless or otherwise) until fit is proper.

Legal & Practical Implications

Primary violation: In Colorado, violations of child restraint laws are primary—a driver can be cited solely for failing to restrain a child properly.

• Fine and infraction: Violating the child restraint system statute is a Class B traffic infraction, typically involving a fine (and surcharge) of about $65 + $6, though amounts may vary.
• Defense & modification: Courts may waive fines if the caregiver shows proof of acquiring or renting a proper child restraint before the court date.
• Liability in crashes: In an accident, attorneys, insurers, or courts may scrutinize whether the child restraint (including a backless booster) was appropriate and properly used. Improper restraint might reduce recoverable damages or be used to assign contributory fault.

If you or a loved one is involved in a car accident and a child was a passenger, or if you received a citation related to child restraints, reach out to Sargon Law Group. We understand how child passenger safety laws interact with injury and liability claims and can help you protect your rights.