Aren't there entire abandoned cities, and yet-to-be-filled suburb developments in the world? Are autonomous driving companies not using those, stuffed full of "stunt" drivers who are employed to do nothing but simulate regular city traffic?
Full disclosure: Google employee, working on nothing to do with Waymo.
[0]: https://blog.waymo.com/2020/09/the-waymo-drivers-training-re... [1]: https://www.wired.com/story/google-waymo-self-driving-car-ca...
Basically stuff the owners don't do, but they're perfectly fine if it happens to others (for the pollution bit, I'm reasonably sure the stakeholders and executives live in nice, low pollution areas).
There's no way it's ready for the sort of adversarial stuff you'd get hiring a bunch of people to drive around simulating traffic for a car. I guarantee it's a great way to find out how your car is at dealing with being cut off, at people running stop signs, etc - and there's certainly value in doing that.
Just, not while you still can't avoid hitting stationary objects along the edge of the road.
Some self-driving cars can't.
At one end, you have the Uber self-driving vehicles which were caught committing numerous traffic offenses by dashcams and cyclist helmet cams within the first days of their illegally testing their fleet on public roads, and then one of their cars ran over a pedestrian that the vehicle's sensors detected but the computers misclassified, somehow - and Uber had disabled the SUV's own auto-braking systems that probably would have saved the woman's life.
At the other end you have Google's self-driving cars have had, I think one at-fault crash across the entire fleet in many, many years and millions of miles of testing? They've been involved in a lot of crashes, but every single one until their one slow-speed scrape with a bus was the fault of another driver. That was 5 years ago or so.
Somewhere in-between is Tesla's FSD "Beta" which, as has been shown by numerous youtube videos (at least, the ones that Tesla doesn't abuse DMCA to take down), behaves extremely erratically repeatedly in the space of less than half an hour in an urban environment. This includes veering off a turn at pedestrians on a curb corner, and in another incident veering toward a light pole. In general, it seems to have a lot of problems making turns.