Google’s driverless car testing programme has clocked up more than two million miles on the road, the team behind it has revealed.

Dmitri Dolgov, the head of the tech giant’s self-driving technology business, revealed the milestone in a blog post, describing it as the human equivalent of “300 years of human driving experience”.

Google car
(Eric Risberg/AP)

 

Google’s autonomous cars have been running on roads in California, loaded with sensors and software to navigate roads but also to constantly monitor traffic as it changes, and keep an eye on any pedestrians and other potential obstacles.

Each vehicle is also being tested complete with drivers and passengers who can take the controls if needed.

Dolgov wrote of the milestone and testing process: “When I first learned to drive, every mile I spent on the road was crucial. It was only through practice that I learned how to move with the flow of traffic, anticipate people’s behaviour, and react to unexpected situations.

self-driving car software
(Google)

 

“Developing a truly self-driving car is no different. A self-driving car that can get you safely from door to door has to understand the nuances of the road, which only comes with experience.”

According to Dolgov, it took Google six years to clock up its first million miles, but just 16 months to complete the second million.

He also explained that while the “first 90% of driving” was easy to master as it revolved around travelling on larger roads and in light traffic, the tech giant was spending its time trying to understand the “final 10%” – including the sudden appearance of roadworks, emergency services or other obstacles that need to be avoided.

“The ability to navigate smoothly on the road, while subtle, is also an important advanced driving skill that helps people feel comfortable whether they’re inside or outside of the car,” Dolgov said.

Google car
(Tony Avelar/AP)

 

“With each mile we drive, our test drivers provide feedback on the car’s movements - things like how quickly we accelerate and brake, the distance we keep from other cars and pedestrians, or the speed and angle we turn. With each piece of feedback, our engineers tweak our software and calibrate our driving behaviour, making our self-driving car feel more natural on the road.

“After 2 million miles of testing, our cars are more prepared to handle rare and unusual situations that human drivers may come across only once in a lifetime.

Google car
(Eric Risberg/AP)

 

“In the last few months, we’ve seen everything from a horseback rider in the middle of the road, to a man wielding a chainsaw in the street (don’t worry, he was trimming trees!), to a couple riding unicycles side-by-side. Today, our cars can confidently handle unusual situations like seeing a car (or three!) driving the wrong way down a road.”

Since beginning its project, Google has been joined by the likes of Uber, Audi, Ford and Mercedes-Benz in the self-driving field, with each of the firms either entering the testing phase, or at least starting to explore how to use the technology.