In the past year Waymo, formerly known as Google’s self-driving car project, has seen marked improvement in the vehicle technology’s ability to execute complex driving tasks without the need for human intervention, according to a company report submitted to California.

In other words, a Waymo car is a quick study and now needs less help from the employee riding along.

To comply with California regulations, Waymo and other companies testing self-driving cars on public roads must submit an annual report documenting incidents in which an autonomous test vehicle disengaged from self-driving mode and required a human driver to assume manual control. These disengagement reports are turned into the California Department of Motor Vehicles.

In Waymo’s most recent report, the company revealed that its rate of autonomous-mode disengagements dropped 75% in 2016 — from 0.8 per 1,000 miles of autonomous driving in 2015 to 0.2 last year. In 2016, Waymo also ramped up its public-road test driving in the state by 50%.

Comparison of Reporting Year Data

Source: Waymo Disengagement Report

“We’ve been able to make dramatic improvements to our technology because we use each of these disengages to teach and refine our car (that’s why we set our thresholds for disengages conservatively),” wrote Dmitri Dolgov, head of Waymo’s self-driving technology, in a recent blog. 

“For each event we can create hundreds — and sometimes thousands — of related scenarios in simulation, varying the parameters such as the position and speed of other road users in the area. This allows us to do a more thorough job identifying the root cause of any disengage and resolving any problems in a robust way.”

To download Waymo’s 2016 autonomous vehicle disengagement report, click here.