Apple has remained tight-lipped over its driverless car technology for years, with only a few leaked documents revealing the existence of the project.

But now the tech giant has shared a progress report on its secretive vehicle tech at a “free lunch” for around 200 artificial intelligence (AI) experts, Wired reports.

According to the website, Apple’s head of AI, Ruslan Salakhutdinov, revealed how the company uses machine learning, a technique whereby an AI trains itself, to hone the vehicle’s self-driving abilities.

Salakhutdinov talked of “using data from cameras and other sensors” to help its driverless systems "spot cars and pedestrians on urban streets”, drive in “unfamiliar spaces” and “build detailed 3D maps of cities”, adds Wired.

According to Digital Trends, the Apple boss also demonstrated the technology’s ability to function in the rain, and how it can identify pedestrians who are “partially obscured behind parked cars”.

However, one thing he didn't reveal is how the Cupertino-based firm plans to commercialise its driverless technology, says Engadget.

Apple is believed to focusing on developing autonomous systems that can be sold to existing car manufacturers, the website reports, rather than developing its own vehicles.

A number of other tech giants are taking a similar approach to branch into the motoring industry.

Chipmaker Intel announced a technical partnership with Google’s autonomous vehicle company Waymo in September. Intel plans to integrate its latest technology into Waymo’s specially adapted Chrysler Pacifica MPVs.

Apple's Tim Cook working on 'The mother of all AI projects'

14 June

Apple is working on "the mother of all AI projects" by "focusing on autonomous systems" designed for the automotive industry, says the tech giant's chief executive Tim Cook.

In an exclusive interview with Bloomberg, Cook said that Apple was working on "probably one of the most difficult AI projects". He added that autonomous systems were "a core technology that we view as very important."

While these systems are expected to be used on autonomous cars manufactured by existing car companies, Cook doesn't rule out the possibility of an electric Apple car in the future.

"It's a marvellous experience not to stop at the filling station or the gas station", he says, adding that "there is a major disruption looming" in the motoring industry.

Automotive industry expert David Bailey told The Guardian that Apple "can offer a number of things such as the software systems that enable the tech to function".

He adds that the company also has the ability to make driverless technology "extremely friendly for a passenger in a way that other tech companies haven't been able to do."

Rumours of an Apple car emerged in September 2015, says Wired, when it was revealed the Cupertino-based tech giant was developing a driverless vehicle under the name of "Project Titan".

These rumours were bolstered the following year. The website says that Apple "sent a letter to the National Highway Traffic Safety Administration (NHTSA) in Washington that alluded to its plans for a vehicle".

The firm also invested $1bn (£785m) in the Chinese ride hailing company Didi Chuxing last year, The Independent reports, but there has been no word yet on how Apple will apply the company's technology to its driverless project.