Since the 1950s, the standard size of soda cans increased manyfold. In 1950, "King Size" was 12oz, but in 2010 it increased up to 40oz!
As sodas contain a lot of sugar, many U.S. schools are now removing soda vending machines from the school grounds (1). Pepsi pledged to remove all full-calorie sweetened drinks from schools in more than 200 countries by 2012 (2). Coca Cola and Dr Pepper followed (3).
However, this does not stop children from going to the next fast-food restaurant (or home) and get one of those 40oz soda cups...