I do not agree with any of your points.

• Traffic will not cease. Even if we see massive improvements in throughput of vehicles, it will not stop traffic jams.
• Cost savings will be minimal, and will probably be wasted elsewhere, like self driving around the block because there is no parking spaces.
• Enviromental impact... this has nothing to do with self driving. And electric means that the gasoline is just burnt elsewhere.
• Safety? Well, I won't be getting into a Johnny Cab.

I do not believe that self driving cars will be a thing in the future.
It is only a bandaid, a temporary solution to a problem that is completely going away. People are moving to cities where they can walk/bike to all places, or they are moving out to the country where there is no traffic, and dirt roads will mean it will be a lot more time before the robots can figure them out.