While on a brief visit to San Francisco last month, I saw several of Waymo’s autonomously driven taxis. It really felt like the future. Sure, most everyone now carries a magic glass rectangle that can tell them just about anything, but smartphones simply aren’t much to look at. By contrast, there was something visceral about the sheer physicality of a driverless car making its way down crowded streets.

I was disappointed to not get a chance to take a ride in one of the robotaxis, but even just spotting them in person was quite something. More than once, I did a double-take as I saw a large white Jaguar SUV moving with no one in the driver’s seat. Even more interesting was seeing the vehicle fully empty as it puttered down the road to its next pickup. When a passenger was present, it still felt like the car had a driver, simply in the wrong spot. But when no one at all was in the vehicle as it was traveling, it really felt like the car had a mind of its own.

Autonomous vehicles are far from perfect drivers, however. Recently, a Phoenix police officer pulled over one Waymo for driving into oncoming traffic. That’s got to be a strange day at the office.