More and more states are requiring children to use a booster seat until they are eight years old and eighty pounds. Booster seats make sense even if your state does not require them. Despite their safety bonuses, a poor fitting booster seat will not help your child in a crash. Increasing numbers of obese children have increased the number of ill fitting booster seats.
In a 2006 study published in the medical journal Pediatrics, 284,000 children age 1-6 faced danger from an ill fitting booster or car seat. As of 2008, more than one in three children is either overweight or obese, increasing the numbers cited in 2006.
That doesn't mean that nothing is being done about it. Car seat and booster seat manufacturers have begun to produce seats with the capacity to hold larger children. Some have also begun to address the issue of a child being too tall for standard seats.
As the American child becomes more and more overweight, manufacturers are catching up with their bodies. Why address the underlying cause of their weight issue? Just make a bigger seat.