Human error is such a surprisingly normal part of our lives, we do it every day but rarely take note of it.

In this report, I’m going to highlight the simple mistakes you’re probably making with your child's restraint every day. I’ll also show you how to correct it.

TWISTED BELTS

It probably seems obvious, but twisted belts are the easiest mistake to make. But in addition to the harness belts you click into place for every single journey, the belts restraining the chassis of the seat to the vehicle also need to be kept flat and straight.

The reason for this is the belts don’t work as effectively when they’re twisted and can cause the seat to move in unintended ways during the unfortunate event of a crash. A twisted seatbelt on your child can become a laceration hazard in the event of a high G-force crash because the edge of a belt can becomes tight and can be sufficiently enough to cause significant damage.

A twisted seatbelt also doesn’t transmit loads as efficiently. When a belt is twisted, it has a narrowed overall width, meaning there is less belt physically holding your child in place. The load is spread over a smaller area; the wider the area, the less severe the pressure. Think of it like the weight of an elephant being placed upon you by standing on a large piece of plywood versus a chopstick, or something.

The kinds of forces placed upon you and your child during a particularly severe crash could be anywhere from 80 G (average) to 160 G (peak). For a split second, obviously. (It’s not sustained G like a fighter pilot.)

Having said that, belts do need to change direction and invert in specific places, and it’s important to make sure they do that as required, and nowhere else. Looking at these images of child dummies during the reaction phase of a crash test, you can see just how dramatically they are thrown around in the cabin, even with correctly installed restraints put in by professional fitters who could do it with their eyes closed.

Untwisting belts as you buckle in your child

Tracing the belt back to its starting point is the quickest way to orient it the right way up. Simply run your fingers along the length of the belt and you’ll feel when it inverts into a cone or tunnel shape. Or, you can simply use the lowest part of the belt, where it goes down into the seat base, to guide you on which side is which.

Because of the nature of seatbelts and buckles in a harness like this, you need to understand that the belt has to invert as it goes into the buckle pathway and up over the child’s shoulders. In the ANCAP images above, you can see how the child’s weight is loaded into the belts as they try to hold the dummy in place.

If these were twisted, the load would be concentrated over a much smaller area and could cause internal damage like torn muscles or burst blood vessels.

Now having said that, you should also understand that it’s actually okay for your child to move slightly during a crash. In fact, it’s essential, because if they didn’t move and remained completely rigid, their internal organs would be damaged and much more tearing and strain would occur on the body. What all these harnesses and seatbelts and airbags are trying to do during a crash is to slow you down and prolong the duration of the crash. This is a physics thing.

Rapid deceleration is very bad for the body. So the seatbelts will give slightly during the peak loads of the crash. This is to gradually slow them down. So having the belts sitting correctly is very important in this highly technical process. All the other safety systems will take care of themselves. It’s up to you to make sure you do your bit.

It’s also good to have those shoulder pads in place around the belt, covering the shoulder and protecting the neck from chafing.

At this point is also good to sight the shoulder height of kiddo relative to the shoulder line marked on all child restraints. Does the head bolster need to be raised as your child grows? Yes. So periodically give it a quick glance and adjust as required.

Untwisting the top tether

The other twists you’re likely to have is in the top tether. This is a very important part to get right.

Loosen off the buckle and start where the strap fixes to the top of the restraint chassis on the non-buckle side. Use this to dictate the orientation of the belt. Run your fingers over the top of the backseat, and down into the anchor clip. You’ll feel that the strap can kinda only face one way up (or out, toward the rear of the vehicle).

Then run your fingers along the belt where you’ll feel it invert into the anchor clip. Depending on which way the anchor clip is facing, you’ll need to make sure the spring-loaded clip can attach facing inwards on the anchor bar. The belt then needs to run into the anchor’s loop path from the inside face, then exit the loop inverted and on the outside face. (See below).

Notice how the belt sits flat over the left-hand shoulder of the seatback, then it stays flat and taught down to the anchor clip, goes through the anchor loop flat, the belt inverts out the loop and stays flat and taught all the way up to the tensioner/reel on the right-hand side. Just ignore that dangling slack belt which should be tucked away neatly into its holder.

BELTS TOO TIGHT

It’s counter-intuitive, but having your top tether and ISOFix straps too tight is not only possible, but potentially harmful.

As mentioned above, the point of a seatbelt is to gradually decrease the speed at which you’re travelling during a crash, which in the language of physics, happens over milliseconds in the time domain. Seatbelts, like the tethers on your child restraint, are designed to gradually reduce the kinetic energy you acquire as a result of being in motion.

The 5-point harness seatbelt (you might have 6 on yours) does not have the pre-tensioner systems used in the vehicle’s seatbelts, so they need to be fairly snug over the shoulders, without making kiddo uncomfortable or squashed. Breathing is required for obvious reasons.

Kids buckling in themselves

Take it from me, with a 5-year-old who's turning 15 soon apparently, that independence and all this “agency” schools talk about can make life better, but also unintentionally worse. So be careful here when it comes to buckling them in.

It's wonderful seeing kids learn how to do things for themselves, but this introduces the potential for important details to get missed, such as listening for that all-important click.

I cannot stress enough how important it is for you to physically, visually and audibly check that Kiddo's buckle has in fact locked into place. In the bustle and pressure of modern day parenting, school and sports commitments, work and all the rest of it, the potential to miss that confirming click is high.

Make sure you confirm each set of buckles click and that their respective belts are not twisted as mentioned above. They should run flat across the shoulder and form a triangle in the way they invert and locate into the bottom or back of the restraint.

Unbuckled seatbelts for restraint attachment

Always keep in mind that if you’re using the seatbelt method for fixing your restraints into the vehicle that your kids, or the dog or various objects haven’t intentionally or unintentionally press the buckle release button.

Using the seatbelt pathway on your child restraint does take advantage of the pretensions system built into your vehicle, but it does mean that with one push of that seatbelt button can leave the restraint unwittingly decoupled from the vehicle (with exception of the top tether, obviously).

So it’s good to routinely check the seatbelt has not been disconnected, and i’d suggest doing this every time you get in.

Try to make it one of the key checks you do when buckling Kiddo in each morning. A quick glance is all you need, because if you have two restraints side-by-side, you can eyeball the opposite side as you're clicking your little ones in.

Give them legroom

It sounds insultingly obvious, but giving your kids some room to.move their legs, especially on the left side is goona not just for their comfort, but also it means their legs don’t crash into the sometimes hard plastic cover on the back of the front-passenger seat.