Is using a child car seat with a harness safer than one you use with a seatbelt?

We would all do anything to make sure our kids are safe, so why settle for second best when it comes to car safety? The simple fact is that a car seat with an inbuilt harness is safer than a booster seat that uses a seatbelt. Transitioning children into a seat in the next category too early is dangerous as they won’t have adequate protection if there is a crash.

Choosing the right car seat

Why do we use a car seat in the first place? The seat keeps children secure just in case there is a crash so it’s important to choose one that is right for your child’s size. Car seats are tested to make sure they meet requirements and we can even tell you which ones perform better than others.

We find that parents of babies are very safety conscious. New parents are most likely to do their research to make educated decisions about what to buy and make sure everything is safe. We all but wrap our little babies in cotton wool and making sure we have the right car seat for them is just one of the many safety checks.

As kids grow older and they’ve survived a few cuts and bruises. The caution we exercised when they were babies and toddlers, relaxes.

By the time Miss or Master has turned 4 and will soon be off to school , we think of them as less fragile. Along with other decisions, some parents may be thinking that it’s time for a big boy or big girl seat? Alarmingly by this time some parents have decided they don’t need a car seat at all which is downright dangerous and illegal!

What car seat do I legally need to use?

By law, children need to travel in a forward facing car seat or booster until they are 7 years old. This is the minimum and experts recommend they continue using a car seat until they are much older.

It’s actually the child’s size rather than their age or weight that is a better predictor of what type of seat they should use. Notice that new car seats have shoulder height markers as guides for when seats need to be adjusted. This also helps work out when a child has grown too tall for a car seat.


Is a seat with an inbuilt harness safer than one that’s used with a seatbelt?

Yes.

There are even some seats on the market with an inbuilt harness that are suitable for children who are over 8 years old.

The difference is when a child is secured in a seat with a harness, the child is better secured and their head and chest will move around less in a crash. This means they are less likely to be injured.

When a child is in a seat with a harness, the child is better secured and their head and chest will move around less in a crash. This means they are less likely to be injured.

Once children move into a booster seat and there is only a single seatbelt securing them, their body will be thrown around more in a crash and they are also at risk of submarining. Submarining happens if a child who is too small to use a seatbelt and they slide down and out of their car seat. The crotch strap on a seat with a harness helps prevent this dangerous situation from happening.

When should I use a stop using a forward facing car seat?

Keep using a forward facing seat until your child outgrows this type of seat. If you can plan ahead and buy one they can use until they’re at least 8 years old, this is ideal. If you have a larger family and have the challenge of fitting 3 seats across the back, this might also be a good practical solution so you’re not fishing between seats for the seatbelt. If your child has outgrown their forward facing seat and it’s more practical to buy a booster seat, try to get one with a 5-star protection rating.

When should I use a stop using a booster seat?

Seatbelts are designed for people who are at least 145cm tall. To see if children are ready to stop using a booster seat and start using a seatbelt, use the 5 step test.

  1. Their back is flat against the seat back
  2. Their knees bend over the edge of the seat
  3. The seatbelt sits across the middle of their shoulder
  4. The seatbelt sits low across their hips and touches their thighs
  5. The child can sit comfortably this way for the entire trip


Let’s not be in too much of a hurry to rush our kids out of their car seats. They will be driving before we know it which is why we should be teaching them about safety as soon as we can and for as long as we can.

Written by Elvira Lazar, Research and Policy Officer
January 25, 2017