[0]https://github.com/SandroMachado/openalpr-android
Companies with a self-driving car fleet will have fantastic amounts of information, considerably exceeding the U.S. spy agencies and law enforcement, about the movements of U.S. persons.
Recording daily activities and movements of cars (uniquely identifiable by plates) is pretty interesting already, associating cars to persons can be made later.
You might even be able to detect suspicious activity, e.g. "KNHX-631 usually just commutes to and from work (shows up going downtown at around 8:30 every day, shows up going uptown 17:30 every day) and one day it showed up at 2:30 driving to leave the city, and returned at 5:30. There's a person reported missing that night..."