While the future of the long-awaited Apple car remains uncertain, it has been revealed that the technology giant ramped up its testing of self-driving vehicles in 2020.

A report filed with the California Department of Motor Vehicles reveals Apple’s fleet of autonomous prototypes drove 18,805 miles in the state last year, up from 7,544 miles in 2019.

Throughout the year, Apple reported 130 disengagements where a human safety driver had to take control of the vehicle, or one disengagement every 145 miles on average. This is an improvement over 2019’s 64 disengagements, or one every 118 miles.

Apple reported its most extensive year of testing in 2018, when its vehicles covered 79,745 miles, but the systems were more rudimentary, with a disengagement being reported almost every mile.

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As noted by Auto News, Apple’s system lags behind its competitors. In 2020, the General Motors-owned Cruise autonomous-vehicle startup reported 770,000 miles of testing to the California DMV and encountered 27 disengagements, an average of one disengagement every 28,520 miles, a significant improvement from over 12,221 miles last year.

Waymo’s autonomous fleet covered 628,839 miles of testing in California in 2020. While that is less than half of what it reported in 2019, it encountered just 21 disengagements, one approximately every 30,000 miles.

News related to Apple’s autonomous vehicle testing program comes just a few days after Hyundai and sister brand Kia revealed its talks about collaborating with Apple on its electric car ended without a deal being reached.