DS is 7 and in 2nd grade. I have not measured his height lately, but he is average to tall for his grade, and I do know that he weighs 54 pounds (on the thin side compared to most of his classmates). Suddenly, it seems all his friends' parents have grown very cavalier about car seats (booster seats). How long is recommended for use of these? DS's booster has a weight limit of 100 pounds, so I had imagined that he would be using it for quite some time. Thanks for any info.
When to stop using a booster (car seat)?
This is probably going to depend on your state law.
Our state says :Requires the operator of a motor vehicle to require each passenger who is at least five years of age, but under eight years of age, and who is not more than four feet nine inches tall to be restrained in a child restraint system.
No, it actually has very little to do with the law -- some states' laws allow 5yos to ride without a carseat or booster.
A child can safely ride in the seatbelt alone if s/he meets ALL of the following criteria:
~ shoulder belt crossing between neck and arm, not riding up on neck
~ lap belt crossing low on hips and thighs, not riding up on soft belly tissue
~ back and buttocks against seat crease
~ knees bending at edge of seat and preferably feet resting on floor
~ able to maintain seating position for entire trip
This generally happens around 4'9" for most kids in most cars. Long-torsoed kids in the tiny backseat of SUVs/minivans may pass sooner; leggy kids in buckety seats may require boosters much longer.
FWIW I just bought a backless booster for my 8 year old. She is legally tall enough to ride without it but the belt doesn't fit her well (in our car at least). Most of her friends no longer use boosters so she was getting a bit fed up with the high back one we had but is OK with the backless one.