Permit me to reiterate an idea I had the last time a self-driving car did something illegal:
All of these cars are being driven by the same software "driver". That driver is in contempt of the law. Thus it needs to be punished like any other driver in contempt of the law. All fines to be paid by its representative human or company. All incarceration to be for as long as is necessary for the driver to be rehabilitated. If no such rehabilitation is possible, the driver is permanently banned from driving.
By which I mean, all Waymos need to be taken off the road until they're provably rehabilitated and it is certain that this won't happen again.
And if Waymo the company thinks that would be detrimental to their business, tough. Take some responsibility and fix your damn cars.