Traditional car seats are designed to be installed in one specific way, and to fit a child with a narrow range of height and weight limits. This can mean that when you take into account rear facing seats baby seats, forward facing infant seats and booster seats, you can have had 5-7 different seats over the course of your child growing up.
A convertible car seat is simply a car seat designed to accommodate a wider range of weights and heights through the use of adjustments.
Traditional Child Car Seats
Car Seats for Babies
Car seats designed for babies and very small children are rear facing, this means when the seat is correctly installed the child is looking towards the back of the car when they are seated correctly in the seat. The reason for this is that more crashes involve the car going forward into objects, and the sudden deceleration of hitting something throws everything in the car forward. With a rear facing child seat the seat takes all of the force of the deceleration rather than relying on a baby’s spine and neck muscles to support their head during the crash.
The recommended age for children to stay in a rear facing child seat is 2 years old, but recently more medical professionals have been speaking out, saying that keeping your child rear facing until 4 years old can significantly reduce the injuries incurred if you are involved in a crash. The problem with keeping your child rear facing until they are 4 is that there are very few rear facing car seats that can correctly accommodate taller children, and it may be safer for the child to be forward facing in a seat that fits them rather than rear facing in a seat that only partially supports their head in an impact.
Forward Facing Child Seats
Once your child has outgrown a rear facing seat they move into a succession of front facing seats. Their first front facing seat is normally similar in design to the rear facing seats, just slightly larger and with a base angled to sit correctly on the car seat when facing forward. The main part of the seat is normally made of a single plastic molding for extra rigidity.
As your child grows you normally have to replace their seat every few years, as they get too large for the seats they are in. While it is tempting to buy a larger seat to avoid having to replace it as often, if you are unable to fully tighten the belts or have your child snugly held you may actually be placing them in more danger than just avoiding the seat completely.
Many of these seats have adjustable shoulder straps to try and get a little more use out of them before needing to replace them, when you adjust the straps always make sure that the point where the strap goes through the seat is above your child’s shoulder, if it is below shoulder level then it can cause injury by compressing the spine if you are involved in an accident.
Booster seats come in two main types, a complete seat, that provides a cushion, backrest and headrest, and one that is just the cushion.
The complete seat should be the first type of booster you get, as the backrests normally have some type of routing mechanism for the cars main seat belt to bring it closer to you child’s shoulder, making it more secure by reducing the chances that they could twist out of the belt in an impact. The additional headrest also provides some sideways support for the head as well as ensuring there is rearwards support for the head if your car has a gap between its seats and headrests.
Once your child has grown to the point that their head correctly rests on the headrest and the safety belt correctly runs over their shoulder you can replace the full booster seat with just a booster cushion until they have finally grown to the point where they no longer need to be boosted for the seat belt to fit them correctly.
A lot of the full seat boosters have a removeable back, so you can transition the seat to a cushion only booster without having to purchase another seat.
Convertible Car Seats
As mentioned earlier, a convertible car seat is one that is adjustable to fit into more than one traditional roll. Normally a seat will combine two of the rolls described above, but there are a few seats that transition between all three rolls.
There are compromises to purchasing a convertible car seat, if we think about a seat designed to be mounted both front and rear facing, it now needs to have an adjustable base so it sits correctly on the car seat in both directions, this means your seat is now being held in the correct position by some hinges and latches rather than a welded frame, or a single molded piece of plastic. This is not necessarily a bad thing, a lot of research and testing goes into those items, and when they are new they are probably as unlikely to fail in an accident than a weld or a weak spot on a mould. My worry is when it gets used for your third child, or has been handed down a few times, and the latches have been worn a little from switching between front and rear facing numerous times, is it still protecting your child as much as it could be?
For the seats that convert between seats and boosters, it may seem as simple as just having an adjustable back with straps that can be removed, but one of my concerns here is that the width of a 35lbs 3 year old is not the same as a 100lbs 10 year old, and to accommodate the later, the former has extra room to move sideways in a side impact.
But, to be clear here, I am not against convertible car seats, they are certainly much better than no car seat, or a traditional seat that is the wrong size for the child, I just have a feeling that a modern car seat, designed specifically for a child of certain proportions with a limited set of adjustments has less chance of failure should the worst happen.