They're gonna cover 98% of cases. The rest can be picked up be remote operators.
For cars there is no way electron-based signal transmission technology can control them with an even marginally acceptable latency.
How do you plan to remote control a moving car with photons?
Edit: Huh, ok. I didn't know radio signals are also photons. Still, the speed of light is significant with sub-second decisions. So even for photon transmission remote control of a moving car in live traffic is not feasible.
Ask the pilots of Air France 447 how well that works out (and they weren't even remote). Oh you can't... they're dead.