Jarrett, an international consultant in public transit planning and policy, continues his role as one of the adults in the room:

… transit agencies are not businesses. They are not monopolizing a profitable business and preventing others from entering. They are running an unprofitable service for reasons unrelated to profit: the functioning of a dense city, the liberty of its citizens, and connecting disadvantaged people to opportunity. Nobody has proposed a way for the private sector to deliver, profitably, on all of those goals. …

Private firms are muscling-in on the elite end of the business. Uber and Lyft may be responsible for about a 6 percent shift in ridership away from transit. But they are also unprofitable, which means they may be unsustainable, even while charging fares that most citizens could not afford for routine travel. To argue that these firms should replace transit is to argue that everyone who can’t afford those fares should be “left behind,” even if our cities had room for the resulting explosion in car traffic. Not even Lyft and Uber make this argument.  Both are eager to partner with transit agencies rather than replace them.

Once we have wide uptake of full automation—sometime between 2020 and 2100 (or never), depending on who you ask—labor cost goes away and driverless taxi fares theoretically get cheaper. But labor cost of fixed transit also goes away. Labor is the dominant element of transit’s operating cost, so driverless buses and trains could be vastly more abundant. Driverless rail has already proven this point. Do you want a train every 4 minutes, even at midnight on a Tuesday? Vancouver’s driverless rapid transit system has been doing this for over 30 years.

So when making comparisons between private and public sectors around automation, you must assume automation on both sides. At that point, the most important issue becomes the efficient use of space: More people in fewer vehicles—high capacity transit—will always be the key to using limited space to liberate the lives of great numbers of people.