To preempt the "this might cause accidents" argument: They did think about this, and the image is placed such it is very unlikely anyone will mistake it for a real child + ball. Drivers will see it coming a long way off and have plenty of time to notice that the image isn't moving.
http://news.ycombinator.com/item?id=1674621
http://news.ycombinator.com/item?id=1673699
http://news.ycombinator.com/item?id=1672968
http://news.ycombinator.com/item?id=1669681
http://news.ycombinator.com/item?id=1656369