GoA 4 (no trained personnel onboard) is only practical for entirely grade separated (ie it's almost impossible for anything else to be there, no cars, no bicycles, no pedestrians) routes.

Even GoA 3 is fraught without this constraint, and for GoA 2 you're still paying for a driver because although the machine does most of the work the human has to handle the inevitable deviations from the model.

GoA 4 railways exist, if you're putting a metro in tunnels or elevating it obviously this is grade separated, and in principle you can do it for long distance rail if you're willing to eliminate at grade crossings (expensive). But they are nothing like a city bus route for example.

>driving a car has been one of the most empowering paradigm shifts for the commons. Being able to travel yourself timely anywhere anytime for any reason

Everywhere that the roads go, sure.

The more other commoners are trying to do this, and the more useful places that the roads will allow it, the slower it gets. But not only that, it's very unevenly paced - and therefore inefficient and less safe.

The problems are compounded by North American road and intersection design. Many urban areas in Europe manage to get by with far fewer streetlights and stop signs (often by using roundabouts). But cars in North American cities routinely get to speeds that would be dangerous in a collision (which would be much less of a problem if this could be confined to routes where they're isolated from pedestrians - but this often doesn't happen), only to have to stop and wait for a minute or more at a time, an embarrassingly short distance thereafter. And then buses have to deal with the car traffic and the lights, make additional stops, and take extra safety precautions due to their size.

Everyone thinks of taking the bus as slow. If there were no cars, the roads could be designed for buses, and streets for pedestrians. But we don't even properly distinguish streets from roads around here.