"LA is a hell for cars made by urban planners who deliberately made it that way."

I agree completely. There is no question——in fact, it's a matter of historical record——that mass transportation, urban layout, etc., were intentionally subverted in Los Angeles by the automobile industry, resulting in the crazy mess we now deal with.

"What problems do you think will be solved by robot cars that shouldn't already be solved by Lyft or Uber (which are functionally identical except for the presence of a human driver)?"

First, there are 9.8 million people living in Los Angeles County. So we'd need to be speaking of an Uber and Lyft ecosystem scaled up sufficiently to service a meaningful fraction of that population, economically, on a daily basis. It seems infeasible.

Second, Los Angeles has some challenging quirks to which human drivers, en masse, are particularly susceptible. For instance, we have very few left-hand turn signals; navigating a left-hand turn at a busy intersection is essentially an ad hoc game of chicken between all participants at that space and time. Some informal "rules" have emerged to navigate such situations, but the social contract breaks down under heavy traffic and its resultant, emotionally compromised drivers. There are also too many traffic lights, which studies have shown to create more congestion than they ostensibly solve for. Very few of these lights are sequenced. As a result, LA drivers are consistently flummoxed by an erratic tempo of starts, stops, and false restarts, forcing the entire "herd" to stumble into each other from the front to the back. And don't even get me started on our downright batshit approach to freeway onramps and offramps. Most important, there simply aren't enough roads, or wide enough roads, to handle the load that LA now brings to bear at every hour of every day -- and building more would involve an exercise of eminent-domain residential and commercial reclamation on a scale unseen in human history.

"Cars will never be able to zoom through a downtown metropolis at 60 mph, unless the city is entirely stripped of pedestrians"

This is a strawman. I don't recall saying that I expected robotic cars to magically make all traffic problems disappear. Rather, I said that they'd do better than we currently do.

"The problems you highlight are NOT caused by human drivers, they are caused by cars, and autonomous or not, those issues will remain."

No, the problems I've highlighted are caused by poor (and in many cases, as we've discussed, deliberately poor) urban planning, made worse by an infrastructure completely inadequate for the scale of the city and its population in 2016. These things impose a cognitive load on LA drivers that is simply too great at the scale LA traffic now brings to bear. The original cause is the layout, and the proximate cause is the humans' individualist navigation of that layout while enmeshed in a giant, uncoordinated swarm.

These are precisely the kinds of conditions I expect a fleet of interconnected, intercommunicative AI cars to do a better job of navigating.

"I don't have these issues because I live in a dense very walkable city and ride my bike everywhere. This is how we should be thinking: cars simply don't belong in cities, and a robot fleet won't change that."

This is handwaving. We can't wipe cities like LA off the map and start over. So we have to make do with the cities we have now. "Cars don't belong in cities" is a nice sentiment, but it's entirely impractical in several of the biggest and most economically important cities in this country.

For whatever it's worth, I'm in wild agreement with you about the unfortunate situation LA is in, and why it's in that situation. And I agree that a car-centric approach is the wrong approach to urban planning. But LA isn't losing the automobile anytime in my lifetime. We have to be realistic about that. So in my mind, the exercise is about making the least of the evil we have to live with.