Waymo closed an oversubscribed investment round of $5.6 billion on Friday led by its parent Alphabet Inc. (GOOG  ) (GOOGL  ) to expand its robotaxi service in San Francisco, Phoenix, and Los Angeles, the company said on Friday.

What Happened: Andreessen Horowitz, Fidelity, Perry Creek, Silver Lake, Tiger Global, and T. Rowe Price participated in the investment round, the company said.

The latest investment will be used to add riders to the company's autonomous ride-hailing service in San Francisco, Phoenix, and Los Angeles. Austin and Atlanta will be added to the list in 2025 through the company's expanded partnership with Uber (UBER  ), said Waymo.

Some of the funds will also be used to advance the company's autonomous driving system, it added.

Why It Matters: Waymo currently operates a fleet of all-electric vehicles that have been customized to enable autonomous driving. The company is delivering over 100,000 paid autonomous rides every week to the public, it said earlier this month.

In July, Alphabet committed to a multiyear investment of $5 billion into Waymo to help the company "continue to build the world's leading autonomous driving technology company."

Waymo is currently the frontrunner in the field of autonomous vehicles in the U.S. While General Motors' (GM  ) Cruise was at par with Waymo until last year, it suspended all of its operations in the U.S. late last year following the involvement of one of its robotaxis in an accident in San Francisco, leading to heightened regulatory scrutiny and the exit of its co-founder and then CEO Kyle Vogt.

Cruise is looking to return to operating driverless vehicles by the end of the year, company CEO Mary Barra said earlier this month.