Here's a real life example of the challenges Google's driverless car faces.
For you city folks, it's not about detecting motion. Once a deer is moving, every rural driver knows it's too late. You have to slow down when you see the deer, before it starts to run across the road.
And it's not about the shape of a deer. There are numerous statues of deer sitting in people's front yards. Is the Google car going to slam on the breaks every time there's a deer statue?
Really, Google can detect a deer? Test drive please.