That's the same thing I brought up "I also envision detection of passive objects (which will not transmit) - radar, sound, or some other technology - as even more critical to the system. We'd never accept robotic cars driving blindly into unexpected obstructions." Automated driving is not feasible in general unless that capability is 100%. The alternative or intermediate scenario is having automation on high-speed throughways which is not engaged on surface streets, which implies restricted access to "robot car" streets.