These are not experimental test vehicles, and this is not a drill. Many of San Francisco’s ghostly driverless cars are commercial robotaxis, directly competing with taxis, Uber and Lyft, and public transit. They are a real, albeit still marginal, part of the city’s transportation system. And the companies that operate them, Cruise and Waymo, appear poised to continue expanding their services in San Francisco, Austin, Phoenix, and perhaps even Los Angeles in the coming months.