You were clear, and I thought I was too. By age 9 I would not have fit in a booster. Had that law been in affect when I was a kid, I would have the choice of doubling over trying to fit into a booster seat or breaking the law. Booster seats are great for kids under certain heights and weights, but the required use of them should be based on that, not strictly age.
I totally agree. All of it should be based on height, but for most parents the age thing is easier to remember. I would imagine it is also easier for officers to determine age numbers because the parent would be able to provide that information easily when asked, than they would if checking height. This would make the law easier to enforce with age requirements than height.
Often times parents are unsure of their children's height and weight. I know I only really learn that information for sure when they have a check-up or doctor's visit.
The booster seat thing is only precautionary to ensure the shoulder seatbelts are able to be worn properly, if you are tall enough to wear them without them comming across your neck, then you should be fine without a car seat.
The same thing about air-bags. Because air-bags are done on a standard basis for any particular make/model, they are designed for a "standard" sized person. I also think with air bags it is one of those things where the potential for negative side-effects is greater when under than standard size than over. So it is definitely something shorter people have to deal with as well. So it is not restricted just to children, but ANYONE under a certain height. And that height, I would guess could vary depending on the make/model of the car that it is installed in.
