Owning a self driving car you can always regulate using taxes etc. If too many people start using self driving cars you would increase taxes on owning those. I don't see that being an actual problem.
that doesn't make any sense though - self driving is a capability, not a type of car. it would be like taxing cars that have cruise control. fundamentally self driving is a safety feature, why would you tax it?
You could tax owning a car more or putting the car in traffic in general, not necessarily self driving aspect of it. The main tax being about taking up room in the streets.
Tolls in cities for traffic control are common where needed. It works well and is simple.