According to this MSNBC.com article, we could be seeing them over the next few years. The development is basically evolutionary, as driver aids are incorporated into more and more cars.
The reason this story caught my eye was that a friend of mine and I approached one of the manufacturer’s representatives at a computer show when I was in graduate school and suggested that it would eventually be possible to create a car that would drive itself. We suggested cameras and image recognition. Now of course we knew almost nothing about the technological hurdles one would have to jump to get there. It just seemed reasonable to us.
The guy scoffed. I assume he either changed his mind or the industry left him behind.