Booster seats offer the best protection for our sometimes forgotten tween kids. And unless you have been trained in crash dynamics, you're probably wondering...
Why do kids need booster seats?
Seat belts were made for the size of an average adult male. Until a child can fit in this adult seat belt, he is not well protected by the seat belt alone. A booster seat raises a child up so that the seat belt will lie on his body in the same place it lies on an adult body.
When a child doesn't fit in the seat belt, he will slouch. (No one is going to sit in a seat with their legs straight out...it's just not comfortable.) This puts the lap belt in a dangerous position on the child's belly. Additionally, a child who is uncomfortable in the seat belt will place the shoulder belt under his arm or behind his back. This, too, can cause serious injury during a crash.
Age, Weight & Height Limits
Ideally, your child should remain in a harnessed car seat as long as possible (while staying within the height & weight limits of that seat). Studies have shown that 5 point harnesses are safer than 3 point harnesses (regular seat belts) and car seat companies have given us all sorts of options for staying harnessed longer.
With that being said, don't move your child to a booster seat until he is at least 4 years old.
Two other important considerations:
The fidgety child
If your child is a bit squirmy, and it's easy to be squirmy when you're a preschooler, she probably won't sit in the booster seat the right way. If she fidgets out of place, she'll be in danger during a crash and you'll wish you hadn't moved her so quickly.
The small child
Some 4 year old kids are just not that big yet. If they still fit in their harness, keep them there. They don't HAVE to move just because they've turned 4. My 5 year old, 46 pound son currently rides in a harnessed Graco Nautilus.
Warning: Even though many booster seats offer a lower weight limit of 30 pounds, there is no reason for the typical child to use one at that weight.
Five point harnesses are the better way to travel and there are so many options out there to keep your child harnessed until AT LEAST 40 pounds!
The upper weight limit on booster seats is growing. Typically, booster seats max out at 100 pounds. However, you will find a few that reach top weight limits of 110 and 120 pounds.
Height limits will vary from 52-63 inches, but most will have a top height of 57 inches.
A child will probably won't be able to fit into the adult seat belt until he is at around 57 inches (or 4'9") so it'd be a good idea to choose one that goes to this height or taller. Note: height alone is NOT the sole indicator for a child to
switch to a seat belt.
Types of Booster Seats
There are two types of boosters, highback boosters and backless (or no-back boosters). Boosters, or Belt Positioning Booster Seats as we like to call them in the Child Passenger Safety field, do not have a harness in the seat. They use a seat belt that has BOTH a lap belt AND a shoulder belt as the harness.
The highback booster looks like a bucket seat and has a high back. These generally have shoulder belt adjusters near the head of the child for proper positioning of the shoulder belt. Many newer models allow you to adjust the back portion of the booster up and down.
Additionally, you may find EPP or EPS foam (like the energy absorbing foam that you find in bike helmets) in the side "wings" next to the child's head for added side-impact protection.
The backless booster is just that...a bottom seat with no back to it. Most come with a shoulder belt adjuster strap that attaches to the booster seat and has a piece of webbing that goes up along the vehicle seat back, which attaches to the seat belt.
Which type is best for my child?
This depends more on your vehicle and your preference than your child. Here's why:
Whatever is directly behind your child's head needs to be above the top of her ears. (This prevents whiplash & should be followed by everyone riding in the car.)
Therefore, if you have low vehicle seats, your child will need a highback booster. If you have tall vehicle seats or adjustable headrests, you may be able to use a backless booster.
Many parents prefer the support that the highback booster offers when children doze off while riding in the car. Instead of the child sliding into an uncomfortable or unsafe position, the child sitting in a highback booster will often rest her head against the sides of the booster seat.
These sides on the highback booster may also provide some additional protection during a side-impact crash, placing a barrier between the child's head and the incoming metal and glass.
CAUTION: When shopping for a highback booster, be aware that a few highback boosters require the use of a vehicle headrest behind them. (Most of these include products from Cosco and Safety 1st, which are both manufactured by Dorel Juvenile Groups.)
How do I use it right?
Place the booster on the vehicle seat in a location with a lap and shoulder belt.
The lap portion of the seat belt should be flat and snug across the upper thighs or lower hips.
The shoulder belt should lay across the middle part of the shoulder, not over the rounded part and not crossing the neck.
It is okay for the shoulder belt to touch the neck as long as this doesn't cause the child to place the seat belt under the arm or behind the back. These positions can cause serious injury during a crash.
If you have a booster that allows you to raise the back up and down to adjust for your child's height, make sure that you continue to move it up as your child grows. The shoulder belt guide on the side of the booster must stay at or above the child's shoulder at all times.
WARNING: It is dangerous to use a lap only belt with a booster seat. Doing so would give the child additional height, which could cause his spine to overextend even more during a crash. This increases the chance and severity of injury to the child's spine.
What will happen if I don't use a booster seat?
A child who needs a booster, but doesn't use one will slouch in the vehicle seat, placing the lap belt over the soft tissue organs...the liver, the bladder, the spleen...all those things we need to live. During a crash the pelvic bones will stop a properly placed seat belt from harming our soft tissue organs. When the seat belt is above these bones, it can tear or damage these soft tissues, most times without tearing the skin on the outside.
Also, if the shoulder belt is bothering a child, he will tend to place it under his arm, which can fracture ribs in a crash, or worse yet, he may place the seat belt behind his back. When this happens, there is nothing holding back the upper part of his body. Therefore, his head will travel forward (or toward the point of impact) until something stops it. This could be the vehicle seat in front of him, which can cause brain damage or the vehicle seat he is sitting on...right between his legs. This overextends the spine and can cause permanent paralysis.