However, if self-driving vehicles do connect to a central system (which I believe they will, as it is the logical step to optimize traffic in real-time) then it'd be rather easily thwarted by the governing bodies.

Privacy and control of movement are two aspects oft overlooked when people discuss self-driving vehicles. There would be nothing to prevent the powers that be from disallowing freedom of motion from a distance that is too far to walk.

It's as simple as no more unauthenticated vehicle movement within 50 miles of the capital, a switch and a change of settings...

I mentioned that every problem looks like a nail, but it's not often that the subject of traffic comes up. So, I'm happy to oblige when it does.

Anyhow, thanks! I'm always happy to contribute. I've sometimes considered writing a short story based on that. I suspect it'd be better done by a better writer than myself, however.