The kind of car seat that a 5 year old should be in is a forward facing car seat that has a tether and harness if they are small enough and are within the weight and height range.
However if the 5 year old cannot fit into the 5 point harness car seat then they should at least be in a back or backless booster seat.
The 5 year old should remain in the harness forward facing car seat until they are at least 7 or until they outgrow the height and weight limit of the car seat.
Then they can move onto a booster soot without a harness.
A harness based car seat is always the safest for the child so they should remain in the harness based car seat until they can no longer fit it in.
However some kids are between the ages of 5-9 when they begin to outgrow the weight limitations of a 5-point harness car seat.
Before you make the move to a belt-positioning booster seat, make sure your child meets these requirements: Generally, kids weighing over 65 pounds are ready to switch to a booster seat.
A backless booster can be used if your vehicle has a seat back that's high enough to support your child's head.
Your child's ears should be below the top of the seat back or head rest.
Backless boosters are less expensive than high back boosters and easier to transport (from car to car, for example).