Then the robot shows up.

It's a white Ford Fusion, wearing an elaborate headdress of spinning lasers and enough cameras to document the Super Bowl. And it's the centerpiece of Uber's latest attempt to disrupt transportation. Starting this morning, pre-selected Uber users in a 12-square-mile chunk of downtown Pittsburgh will have the option to ride in a self-driving car—with a human engineer at the wheel who can take over if things get dicey.

Uber has a straightforward goal: become even more efficient and profitable by jettisoning the human drivers who take home the majority of their customers' money. Or, as one Uber engineer puts it to me: getting rid of the overhead. (Putting a dent in the annual global rate of 1.2 million road deaths every year would be nice, too.)

"That pilot really pushes the ball forward for us," says Raffi Krikorian, who runs Uber's Advanced Technologies Center, in Pittsburgh.