This is a shocking video of a toddler falling out of their family van. The reminder is obvious. Lock all child safely locks, but put your child in a car sear every time. If you go to the original YouTube video, you'll see that a nice lady picked up the child and saved it. And be sure to read the article at this link. DOUBLE CLICK TO ENLARGE.
WHEN SHOULD I CHANGE MY CHILD FROM A CAR SEAT TO BOOSTER
My daughter was always larger and taller than the normal baby. She was in the 98%. I had to call the government at one point to find a booster (but it was a big car seat, which I liked better) that would fit her at 4. Always call the police or fire department for advice, especially when your child starts unlocking the safety locks on the sear.