Just like for human drivers, the key to learning is practice. That’s where our simulator comes in. Waymo’s simulator is a realistic virtual world where we can recreate every real-world mile we’ve driven. Each day, as many as 25,000 virtual Waymo self-driving cars drive up to 8 million miles in simulation, testing out new skills and refining old ones. Like athletes visualizing the playing field, our virtual cars envision various scenarios and practice maneuvers that help them safely navigate the real world.