Waymo chief executive John Krafcik announced that the company has completed 8 million miles of testing with its self-driving vehicles on public roads.

In recent years, Waymo’s fleet of autonomous prototypes have been rapidly raking up additional miles of testing. In June 2015, its vehicles had completed 1 million miles on public roads. That figure grew to 4 million miles in November 2017 and it has taken just eight months for that total to double to more than 8 million miles.

This translates into roughly 25,000 miles per day. While Tesla likes to claim its Autopilot system is light years ahead of its rivals, it lets its owners do a large proportion of its self-driving testing for it, a method which has raised more than a few questions. On the other hand, Waymo’s technology is tested solely by the company and won’t be introduced into the market until it is perfected.

It’s not just Waymo’s public testing figures that are impressive. In the same time, Waymo has also driven more than 5 billion miles in simulation, approximately 8 million miles a day. Simulation testing allows Alphabet’s self-driving unit to practice situations that rarely occur on the street and allow its machine learning software to become more advanced, The Verge reports.

Waymo has just over 600 self-driving Chrysler Pacifica minivans as part of its test fleet on public roads. The company has inked a deal with Fiat Chrysler Automobiles to add an additional 62,000 Pacificas to this fleet and landed a deal to acquire 20,000 units of the all-new Jaguar I-Pace, too.

At its current rate of testing, Waymo expects to be able to launch an autonomous paid taxi service later this year in the United States.