(Disclaimer: I'm a bike advocate, so I may have a different perspective on some of this than most.)
Our car-based transportation system is far and away the most dangerous thing any of us accept doing on a daily basis. 40,000 die a year.
But when cases come to court, everyone on the jury has in the back of their mind "that could have been me if I lost concentration at the wrong moment, or made one bad judgement, etc etc."
So penalties are comparatively light for traffic fatalities. Big punishments are only meted out if the case is so egregious -- repeated drug use, flagrantly reckless behavior -- that the jury can be convinced that the driver is different from them.
In other words, drivers don't get punished for doing something dangerous, because everybody on the road is doing something dangerous. They get punished for doing something more dangerous than the norm.
In this case, there's no question that the "driver" is different than the jury -- it's a computer. Now the symmetry that made jurors compare themselves to the accused is broken.
The result, and what self-driving car advocates don't get, is that self-driving cars don't just have to be safer than human drivers to be free of liability, they need to be safe period. In a trial, they don't benefit from the default "could have been me" defense.
That's a HUGE requirement. In fact, it's probably impossible with our current road system. It won't just take better self-driving cars, but better roads and a major cultural change in our attitudes about driving.
As a bike advocate, I welcome this shift, but I also see how deluded many of the current self-driving projects are. Software moves fast, but asphalt and mentalities move slow. We're not years away from a self-driving transportation system, we're decades.
And this trial is just the beginning of that long story.