"expecting the driver to look up from their phone"
What part of "the driver isn't supposed to be looking at their fucking phone in the first place" isn't sinking in?
Yup. In this case, the driver was apparently happily texting while the Tesla drove into the back of the police vehicle. So an easy ticket for the officers involved, and hopefully the driver will be prosecuted for texting and the US version of driving without due care and attention. And the US police take a dim view of been driven at, so could have shot the driver and/or car.
But this is the danger of perceived 'autonomous' vehicles, when driving is probably the most hazardous activity that people do regularly. I totally agree with the comments that driving aids are good, but drivers still need to pay attention to their driving.