It is a perfectly comparable scenario. My Honda Civic already has a sense of its surroundings, and it's not "self driving" at all. It knows when I'm swaying out of the lane, it knows when I need to slam on the brakes. And that sense will only improve as we do take the step into full automation.

Cars that are using signals from the street won't ever be only relying on those signals, they'll be relying on visual and audio (sonar/ultrasonic range finding) methods as well.