Autonomous vehicle companies with permits in California drove over 9 million test miles in autonomous mode in 2023, a significant increase from around 5.7 million miles the previous year, according to the California DMV's latest disengagement reports.

The majority of miles - 5.8 million - were driven with a safety driver present, while 3.3 million miles were fully driverless. Thirty-eight companies currently have permits to test autonomous vehicles with drivers, and six companies - including Waymo, Cruise, Zoox and AutoX - have permits for driverless testing.

The DMV report tracks when autonomous vehicles hand control back to a human driver, known as a "disengagement." This year saw 6,570 total disengagements, with Zoox averaging the most miles driven per disengagement at 177,602. Waymo covered the most total autonomous miles at 4.9 million, including 1.2 million driverless miles.

Cruise had the second most miles at 2.6 million driverless and 584,000 with drivers. However, Cruise and a couple other companies reported zero disengagements for the year, raising questions about reporting consistency across companies. The metrics also don't reveal insights about testing conditions and difficulty.

For the first time, companies specified whether disengagements came from the vehicle system itself or human drivers. Over 2,300 of Apple's reported disengagements came from drivers, hinting their vehicles may have been capable of continuing autonomous operation in some cases.

The report highlights how a few major players - Waymo, Cruise and Zoox - account for the bulk of California's autonomous vehicle testing activity. However, many metrics rely on self-reported data that isn't independently validated, making precise comparisons difficult. Still, the increasing miles driven points to ongoing progress in autonomous vehicle development in the state.