Seeing cars​ with no human inside move through San Francisco’s streets is eerie enough as a pedestrian, but when I’m on my bicycle I often find myself riding alongside them, and from that vantage point you catch the ghostly spectacle of a steering wheel turning without a hand. Since August, driverless cars have been available as taxis hailed through apps but I more often see empty cars than ones with backseat passengers. These robots in the shape of cars don’t move like those with human drivers....