Waymo, the self-driving unit of Google’s parent firm Alphabet, has raised $2.25bn in its first external investment round.

The round was led by Silver Lake, Canada Pension Plan Investment Board and Mubadala Investment Company.

Other investors, such as Magna International, Andreessen Horowitz, AutoNation and Alphabet, also participated in the funding.

Waymo CEO John Krafcik said: “We’ve always approached our mission as a team sport, collaborating with our OEM and supplier partners, our operations partners, and the communities we serve to build and deploy the world’s most experienced driver.

“Today, we’re expanding that team, adding financial investors and important strategic partners who bring decades of experience investing in and supporting successful technology companies building transformative products.

“With this injection of capital and business acumen, alongside Alphabet, we’ll deepen our investment in our people, our technology, and our operations, all in support of the deployment of the Waymo Driver around the world.”

Waymo was founded in 2009 as a small project inside Google to explore self-driving technology. Now, the company operates as a standalone unit and focuses on the development of fully self-driving vehicles.

According to the company, the Waymo Driver has completed more than 20 million miles of journeys on public roads.

Waymo One, its ride-hailing service, is currently operational in Arizona.

The Alphabet subsidiary has also unveiled Waymo Via, a self-driving truck for transporting goods.

This latest fundraising comes just a week after Pony.ai, a Chinese autonomous vehicle technology company, raised $462m. The round was led by Japanese automaker Toyota Motor.