I think in this demo they simply paint a path for the car to follow. The cones etc are there just to help us see whether it's following the path well. If there was a cone in the middle of the path, it would've run right over it.
What would impress me (seriously). I go out the L.A. Colliseum parking lot, set up cones / a track that the car can definitely do (based on radiuses & turns in this video), the car "studies" the track (I don't care if a drone looks at it & takes measurements), and then the car calculates and executes a perfect path through the course the first time without hitting anything.
Again, not trying to crap on this, I'm just saying that anyone who's worked in controls, automation, engine control, etc. (I've done all these & more) isn't utterly wow'ed by this. Kudos, but we didn't just put a man on Mars.