I think ambulances and firetrucks should be basically the only automobiles. Even most delivery vehicles should be replaced by either cargo bikes or by spur lines off the railroad.
Also, it's important to this discussion to draw a clear distinction between streets, roads, and stroads. Streets are destinations and can be made primarily for bikes and pedestrians, roads are routes for cars to go fast from place to place. Stroads are the cursed middle ground common to USAmerican suburbia which combine the width and car friendliness of a road with the density of destinations of a street. I don't think it's possible, or even desirable, to get rid of streets, but I think we can and should get rid of most roads and absolutely all stroads. The remaining impermeable surfaces will be drastically cheaper to maintain.