The California Department of Motor Vehicles has released data from companies who tested self-driving cars on the state’s roads last year. Not surprisingly, the two best performers have been working on autonomous vehicles for a long time. Wired reports:

The Golden State, home to many of the companies leading the robo revolution, has some of the strictest rules for AVs in the country. Operators who run cars on public roads must publicly report any crashes they’re involved in. And at the end of every year, they must hand over data on how many miles they drove and how many times their onboard human safety driver had to take control from the machine—that’s called a disengagement. Combine those, and you have a number approximating how far any company’s self-driving car can go without human help. Something like a grade.

The metric is imperfect, and this data comes with a crate of caveats. But before we get into those, know this: Waymo (formerly known as Google’s self-driving car project) and General Motors appear to be leading the pack and making rapid progress toward the day when human drivers, with all their inattention and distraction and tendency to crash, will be obsolete.