I tell my kids 13. I always thought it was about bone density more than size. I did let dd3 start sitting up front a few months before her 13th birthday though. She helps at our seat check events and has to ride in front when the back is full of seats and other supplies. It just kind of carried over.
Same here. I know the study said 14 and older do better, which MAY be due to bones, muscle density over size. But with dd, I see her moving up front by Sept next year when she turns 13. I figure she's going to be at least as tall as I am, maybe even taller by then.
Currently, she's near/over 5'2 and around 100lbs. She's muscular and strong. One of her besties is the same age, same height, but only around 80lbs. Stick kid who experiences injuries all of the time.
Comparing the two just in maturity & muscle structure, dd seems a lot older than her friend. I don't know if that would make a difference in a study or not. :shrug-shoulders: And it's something that isn't easily tested out either.
When the car is full of kids, as it was on Friday, I now don't hesitate to put dd in the front seat. I just adjust it to a higher setting & ensure the belt adjuster is set low. The seat's already back as far as it can go.
Full time? I don't know. But next year in the fall, if she wants to ride up front, I'm really not going to fuss.