What are the child car booster seat laws?

Plus, the pros and cons of booster seats

7 minute read

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We break down the child booster seat regulations and explore how they make travelling in cars safer for kids. 

  • What are the current booster seat regulations?
  • Will my existing booster seat be affected?

Use our handy guide to learn about the new laws

When your child outgrows their car seat, it’s time to find a new one suits your child and fits in your car – as well as seeing if it’s covered by your car insurance. However, you’ll also have to get your head around the booster seat laws, which build on the child car seat laws.

But worry not; with the help of Julie Dagnall, co-director of Child Seat Safety (@carseatladies) and the Child in Car safety advisor for Road Safety GB (@Road_Safety_GB), we've compiled this handy guide to the child booster seats laws.

What is a booster seat?

A booster seat is designed for a child, usually aged four years and older, who has outgrown Group 0 and Group 1 rear- and forward-facing child seats. It's designed to recreate the protection afforded by an adult's fully developed pelvis, and also raises a child so the car's seatbelt, otherwise designed to fit adult occupants, can restrain them safely. 

There are two types of booster seat: a high-backed booster seat and a backless booster seat, also known as a booster cushion. Depending on the weight of the child they can carry, they may be Group 2 or Group 3 booster seats – although many seats have adjustable elements so that they can be adapted to Group 2 or 3.

What's a high-backed booster seat?

A high-backed booster seat can be used with children weighing from 15kg, and looks a lot like a child safety seat. However, it's forward-facing only and doesn't have an integral harness to secure the child. 

Instead, the child is secured using the car's seatbelt, which secures the seat to the car. If your car has Isofix child-seat mounting points, your Isofix-compatible high-backed seat is secured directly to the car, while the seatbelt secures the child to the seat. 

What are the advantages of a high-backed booster seat?

This type of seat allows you to position the straps of a seatbelt correctly. Because a child's bones still aren't at full strength, the high-backed booster seat is designed to provide similar protection to a fully developed adult pelvis and collarbone in a collision, reducing the chances of broken bones and spinal injuries. At the same time, its side wings protect the child's head and reduce movement in a side impact. Others have adjustable head restraints that also reduce head movement.

If your child's car seat gets damaged, you should buy a new one. Your car insurance may cover replacement child car seats.

What's a backless booster cushion?

This seat can also be used by children weighing from 15kg – but it's not secured to the car either by the seatbelt or Isofix connectors. Instead, it's simply a way of raising the child so the car's seatbelt secures them more safely than if they were sitting on the vehicle seat alone.

Some booster cushions have small 'horns' located by the child's hips. These are there to guide the seatbelt across and stop it sliding up in a collision and causing spinal injuries.

What are the disadvantages of a booster cushion?

A booster cushion doesn't have a back, and offers no means of correctly positioning the seatbelt at the shoulder and across the chest. It doesn't provide additional support in the way of side wings or a head restraint.

Safety organisations advise against using booster cushions.  Some high-backed booster seats have removable backs so that you can convert them to booster cushions, but safety organisations also advise against this.

Tests have shown that young children are especially vulnerable in crashes. Pre-tensioning seatbelts can exert huge loads on a child's ribcage, while the size of their heads relative to their bodies means they move around more violently, causing greater injury. A child in a booster cushion is especially at risk from side impact injuries, too. 

What regulation governs booster seats and cushions?

Regulation ECE R44/O4 applies to high-backed seats and booster cushions and covers children from birth to 36kg. In addition, UK road traffic law demands all children travelling in a car must use the correct car seat until they are 12 years old or 135cm tall.

The use of booster cushions (also known as backless booster seats) is limited to children taller than 125cm and weighing more than 22kg. These products display a sticker stating what height and weight of child they can be used for. 

Should I use a booster cushion?

You can continue to use your existing booster cushion if it conforms to ECE R44/04 Group 2 – 15kg minimum weight. But safety organisations say booster cushions provide insufficient protection, and don't generally recommend them. Instead, if they've outgrown their Group 1 seats, young children should travel in a high-backed booster seat until they are 150cm, the height car seatbelts are designed for. The government’s website has more information about the car seat laws.

Do I need to replace a booster seat if I have an accident?

A child's car seat should always be replaced after an accident, even if there doesn't appear to be any damage. with LV= car insurance, we’ll replace any child seat with a new one of the same quality, even if it looks un-damaged after a theft, accident or fire.

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All content is approved by our in-house advisory board of experts.