Child car seat manufacturers recommend that children do not wear bulky clothes when fastened in a child seat.
Secondly, the straps should not be too tight nor too loose! It is said that there should be enough room to just slide your hand underneath the chest harness element of the five point harness.
Chest clip / buckle – WARNING
The chest buckle should be level with the axilla (arm pit) so that it is resting on the sternum.
It stands to reason that having a hard bulky chest buckle on a child’s car seat is a significant factor in causing either thoracic or abdominal trauma in the event of an accident (award winning alternative). A toddler’s rib cage has not yet ossified and any trauma from a crash will penetrate through to the organs and arteries and not be dissipated around the rib cage.
A child’s chest experiences forces of up to 60g in the event of a collision at just 30mph. The chest buckle may not break on impact creating a hard surface that can add considerable force to a child’s internal organs.
The 5 point plus is a safer solution than the chest buckle (read how does it work?) as it solves the design flaw in standard five point harness car seats.
Ensure that the harness is not twisted. During crash testing we found that a number of car seats had twisted harnesses when taken out of packaging. If strap is twisted, the load on the child under sudden braking will be far greater and will easily cut in to the child. It also makes the adjustment of straps more difficult.
Regularly check that your car seat is attached firmly, particularly non isofix models. Make sure that it does not wobble or slide.
At 30mph, an impact can create up to 60g of force, so any movement will be very dangerous to your childs’ health.
It is recommended that when installing your childs car seat that you bear as much weight on to the car seat (e.g. kneel on it) to squash the padding of the seat that it is resting on. If you don’t, the significant forces at the time of a crash will squash the car seat, the child seat may move forwards, endangering the childs head on the seat infront.
If you have leather car seats and are not using an isofix child car seat then it will be harder to get a rigid fit.
Where possible we recommend using isofix car seats. We didn’t use isofix with our son but now knowing how much can go wrong with the fitting of non isofix seat and the consequences during a low speed crash, we shudder at the extra risks he was exposed to. Whenever possible, always have the passenger seat in front of your child pulled as far forward as possible, particularly with non isofix models, to minimise the risk of your child hitting the back of the seat in the event of an accident.
Typical life span of a car seat is just six years unless it has been involved in an accident then it should be disposed of safely (cut the straps so that no one else can use it).