In your thought experiment there is still a scenario where there is a car driving around driverless, if even for a short amount of time. That's a new increase i

In your thought experiment there is still a scenario where there is a car driving around driverless, if even for a short amount of time. That's a new increase in traffic beyond what we have now. This is only the most extreme edge case and it's not worth focusing too much on. The scenarios examined in the KPMG study the blog post cited are more typical and more concerning. That study finds that there will be a very significant increase in traffic due to people younger and older than current drivers that could never drive before now being able to drive. It is a good thing that we are expanding access to transportation for people that had poor access before, but achieving this using autonomous vehicles will certainly increase the amount of cars on the road.