Nearly everywhere on earth, when you’re stuck in traffic, you’re still surrounded by the usual sea of heads attached to shoulders attached to arms attached to steering wheels. But in a tiny handful of places—in Los Angeles, Phoenix, San Francisco, and Wuhan, China—you can find yourself flanked by taxis with no one in the drivers’ seats, picking up passengers, unsupervised by any human. And if you live in one of those cities, the sight probably doesn’t even prompt a double-take anymore. It’s like the future is suspended between those who’ve…
