Inside Waymo's Secret World for Training Self-Driving Cars

In a corner of Alphabet’s campus, there is a team working on a piece of software that may be the key to self-driving cars. No journalist has ever seen it in action until now. They call it Carcraft, after the popular game World of Warcraft.

The software’s creator, a shaggy-haired, baby-faced young engineer named James Stout, is sitting next to me in the headphones-on quiet of the open-plan office. On the screen is a virtual representation of a roundabout. To human eyes, it is not much to look at: a simple line drawing rendered onto a road-textured background. We see a self-driving Chrysler Pacifica at medium resolution and a simple wireframe box indicating the presence of another vehicle.

Months ago, a self-driving car team encountered a roundabout like this in Texas. The speed and complexity of the situation flummoxed the car, so they decided to build a look-alike strip of physical pavement at a test facility. And what I’m looking at is the third step in the learning process: the digitization of the real-world driving. Here, a single real-world driving maneuver—like one car cutting off the other on a roundabout—can be amplified into thousands of simulated scenarios that probe the edges of the car’s capabilities.