This: http://en.wikipedia.org/wiki/EUREKA_Prometheus_Project seems to indicate that trials/experiments have been on-going for many years, in various European countries. Perhaps it's a EU thing, so that Spain is included by default.
When does a car become self-driving? I imagine that distance control is legal (i.e. cruise control where the car will brake and accelerate to maintain distance behind the car in front, up to a maximum speed), and this is a further extension with steering. There's still a person driving the truck at the front.
though lots of newer cars also have lane assist (so if you're drifting our of your lane without signalling, it will steer you back in).
I think it's becoming clearer that there's no strict dividing line between computer-driven and human-driven.
Rather, we'll slowly move to more and more being done by computer, and less and less done by the human (in this example- the computer taking over the motorway driving, and then handing over to you when its time to return to the normal roads).
This was also covered in the article about the Google car last week, which hands over to humans when it gets into a sticky/narrow situation.